1.0

~~~

:

~W

I&.l II:

I

::

111111.25

.......

..

1.0

.2

~

M

~

W ~

I

.0

iii

1.1

2.8 1~

~W

I&.l

W

~

1.1

25

'"11 .

::

......

..

11111

25

.

2.2

W ~

M

I

IIIIIJ .4

111111.6

MICROCOPY RESOLUTION TEST CHART NATIONAL BUR[AU

or

STANDARDS·1963-A

111111.25 111111.4

11111 1.6

MICROCOPY RESOLUTION TEST CHART NATIONAL BUREAU

or

STANDARDS-1963-A

LIBRARY USE ONLY /b69 ~~Lunited States

~~J) Department of

~_ Agriculture!

~

Soil Conservation Service

__Technical , -~~~~~ Number

~

Reiationstlips Between Soil, Plant Community, and Climate on Rangelands of the Intermountain West

Passey, H. B., Vern K. Hugie, E. W. Williams, :.md D. E. Ball. 1982. Relationships bet-vI'een soil, phmt. community, and climate on rangelands of the Intermountain West. U.S. Department of Agriculture;, Technieal Bulletb No. 1669.

Abstract Studies were made to determine t;ne range of soil, climate, and vegetation characteristics consistently associated under natural conditions. Eighty-five study sites were selected within 32 relict areas in northern Utah, southern Idaho, northeastern Nevada, and west-central Wyoming. Studies were conuned to climax plant communities characterized by associations of sagebrush, bluebunch wheatgrass, Sandberg bluegrass, and Idaho fescue and by Entisol, Aridisul, and Mollisol soil orders. Soil subgroups provided the most meaningful level of soil classification for correlation with broad plant associations. The presence of different species or subspecies of sagebrush provided the most meaningful grouping of plant communities. Vegetation production and composition data were recorded for 10 consecutive years on 17 key study sites. Annual and periodic fluctuations in total production and yield of individual species b response to climatic variations were analyzed. Year-to-year differ­ ences in productiol~ were greater on sites with deeper soils and higher precipitation than on sites with shallower soils and lower precipitation. Fluctuations in production of in­ dividual plant species were inconsistent and erratic. Growing conditions favorable to some species were Unfavorable to others. Production was positively related to precipita­ tion, but the relationship was too broad to be of pract.ical interpretive value for range management. Broad positive correlations also were observed between total annual pro­ duction and soil organic-matter content, soil nitrogen content, amount of plant litter, percentage of soil covered by plants, and basal area of plants. Soil properties modify the effects of climate on plant communities; likewise, variations in weather conditions modify or mask the effects of specific soil properties on plant growth and distribution. Nevertheless, climax plant communities protected from abnor­ mal disturbance serve as valuable benchmarks for soil survey interpretations on range­ land.Effects of soil, plant, and climate relationship~l on relict areas may be used to approximate productive potential of other areas of the sa:me or similar soils. KEYWORDS: plant associations, vegetation production, relict areas, climax plant com­ munities, sagebrush, soil subgroups, vegetation composition, soil orders.

Acknowledgments This publication was prepared with the cooperation, assistance, and encouragement of many individuals and organizations. To attempt to list all who made significant con­ tributions would be futile, but their help is appreciated. Soil Conservation Service personnel from field, area, state, regional, and national offices cooperated in collecting and processing field data and in preparing this publication. The study was conceived by Guy D. Smith, Director, Soil Survey Investigations Division, now deceased, and Fred G. Renner, Chief Range Conservationist, now retired. William M. Johnson, Deputy Chief for Technical Services (ret.) directed the study during the first several years. Appreciation is extended to Waldo R. Frandsen, regional range conser­ vationist (ret.), and T. B. Hutchings, state soil scientist of Utah, who were closely asso­ ciated with the field and office work, and whose help was most timely. Profeeaor A. H. Holmgren, curator of the Intermountain Station Herbarium at Utah State University, identified all plant specimens. Dr. Kimball T. Harper of Brigham Young University assisted in the analysis of field data. Personnel of the Agricultural Research Service; Forest Service; Bureau of Land Management; National Park Service; Utah, Idaho, Wyoming, and Nevada Agricultural Experiment Stations; and universities within the study region cooperated. Recognition must also be given to the many ranchers and farmers who expressed an interest in the study and kindly provided access to their land. September 1982

Contents Page

Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Objectives and Justification. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Scope and General Description of the Study Region. . . . . . . . . . . . . . . . . . . . . . . . . . . Physiography, Geology, Soils, and Land Use................................ Climate................................................................. Methods................................................................... Study Sites. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Plant Nomenclature. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Study Site Delineation. . . . . . . . . . . . . . . . . . . . . . . . . .. . . .. . . ... . . . . . .. . . .. . . .. . Vegetation Studies. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Soils.................................................................... Climate................................................................. Data Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Results and Discussion. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Vegetation Groups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Group I ................. , . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Group II .............................................................. Group III. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Group IV ................................................ ·············· Group V............................................ ··· .... ············ Group VI ........................................ · ...... ··············· Group VII. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Group VIII ......................................................... '. . . Group IX ............................................. ·· .... ··········· Variations in Productivity of Plant Communities. . . . . . .. . . .. . . . . .. . . . . .. . . . Fluctuations in Production of Individual Species. . . . . . . . . . . . . . . . . . . . . . . . . . . . Precipitation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Temperature. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Soil Moisture. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Soil..................................................................... Occurrence and Production of Plant Species. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Other Factors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . Special Situations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Range Condition Trend. . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . .. . .. . .. . . . . . . . . . Plant cover. . . . . . . . . . . .. . . . . . . . . .. . . . . . . . . . . . . .. . . . . . . . . . . . . . . .. . . .. . . . Plant vigor .................................................... , ..... , . Soil................................................................... Conclusions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Sagebrush and Plant Communities. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Summary and Conclusions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Literature Cited ........................................................... Appendix Exhibits. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1

2

3

3

5

6

6

7

8

8

10

11

11

12

12

16

16

17

17

18

18

18

18

25

25

25

27

31

33

35

37

44

45

45

46

47

47

48

48

48

50

53

UNIVERSITY .... OF Ct,LlFOR0;IA I DAVIS .

JAN 2'1 1983 GOV'T. DOCS~ - LfBI\ARY

List of Figures Page 1. Land resource regions, major land-resource

areas, and project study locations .............. 4

2. Monthly and annual precipitation at Counc

and American Falls, Idaho, and Lander,

Wyoming .................................... 6

3. Three clustered 0.89-m 2 (9.6-ft 2) plots near

central point of a study site ................... 9

4. Current season's growth of herbaceous vegetation

clipped to ground level ........................ 9

5. Paper bags suspended from U-shaped iron rod,

6 mm (~ in) in diameter, with ends pushed into

ground....................................... 9

6. Soil pit excavated to bedrock or below indication

of soil development ........................... 10

7. Plant-species association groups derived by chi­ square analysis ............................... 13

8. Plant-species association groups derived by

frequency correlation ......................... 14

9. Study-site association groups derived by plant­ species frequency correlation .................. 15

10. Natric horizon, B2t of Brunt silt loam, heavy

subsoil variant ............................... 17

11. Soil profile and vegetation on Clegg soil, Carey

Kipuka study site ............................. 29

12. Soil profile and vegetation on Bancroft soil,

Carey Kipuka study site.............. , ........ 30

13. Mean weekly temperature and average weekly

precipitation at Craters of the Moon National

Monument .... \ .............................. 33

14. Total annual production and production by

species on Clegg silt loam, 1959-68 ............. 34

150 Total annual production and production by

species on Bancroft silt loam, moderately deep

over bedrock variant, 1959-68 .................. 35

16. Flow from thawed, supersaturated All horizon

running over edge of soil pit ill Neeley silt loam,

moderately deep over bedrock variant .......... 37

17. Water removed by plants from Bancroft and

Clegg soils ................................... 38

18. Total annual production (air dry, kg/ha) and

precipitation on four soils in the Carey

Kipuka ...................................... 40

19. Colony of wild onion (Allium passeyi) .......... 44

20. Soil profile of Newdale silt loam, showing

activity of cicada nymphs ..................... 44

21. Effects of frost heaving on Sandberg bluegrass .. 47

22. Polygonal soil-surface pattern with segregated

coarse fragments on ungrazed relict ............ 48

ii

List of Tables Page

1. Maximum and minimum monthly precipitation

at Aberdeen, Idaho, for the 10-year period

1958-67 ..................................... 2. Prevalence index of key plant species included

in computer analysis, ........................ 3. Grouping of vegetation by dominant species ... 4. Total annual production for 17 study sites with

10-year production records ................... 5. Mean and standard deviation of production

(kg/ha) of selected plant species on 17 study

sites with 10-year records .................... 6. Coefficients of correlation between adjusted

weather-station precipitation records and 10­ year total production from 17 study sites ...... 7. Average annual precipitation and average precipitation for selected periods from rain­ gage records at six study locations, 1961-69 .... 8. Coefficients of correlation between total annual

production and periods of precipitation for

eight selected soils ........................... 9. Mean soil temperature at depth of 61 cm

(24 in) ...................................... 10. Average percentage of October-March precipi­ tation retained in soil at beginning of growing

season, 1961-69 .............................. 11. Dry matter produced per centimeter of water

used on 17 repeat study sites ................. 12. Percentage of micro plots of various parent

materials in which selected plant species occur

(1,660 microplots) ............................ 13. Percentage of microplots in which individual

plant species occur, by soil order, group, and

subgroup.................................... 14. Total annual production and composition by

species, Clegg stony loam, moderately deep

over bedrock variant, 1958-61 .................

7

12

19

26

28

31

:h 32

32

36

39

41

42

46

RELATIONSHIPS BETWEEN SOIL, PLANT COMMUNITY, AND CLIMATE ON RANGELANDS OF THE INTERMOUNTAIN WEST B. B. Passey, range conservationist (retired) Vern K. Bugie, soil scientist (retired) E. W. Williams, range conservationist (retired) D. E. Ball, range conservationist (retired)

Introduction

Ear\y ecological research on intermountain vegetation was directed primarily toward identification and differentiation of existing major plant associations. The sagebrush­ bunchgrass association, for example, was separated from the adjoining salt-desert shrub community and the bunchgrass­ prairie association largely on the basis of differences in dom­ inant plant species. Most early plant-community studies were stimulated by a desire to understand the value of plant species or groups of sped~s for livestock grazing or as indicators of soil suit­ abilitlf for cultivated crops (Kearneyet a1. 1914, Shantz and Piem4liseI1924, 1940). These studies lacked quantitative data on the productivity and composition of plant associations. They were based on existing vegetation rather than climax plant communities. In some of the early pUblications on plant-soil relationships (Weaver 1917, Clements 1920, Shantz and Zon 1924, Shantz 1925), gross differences were recognized in soil characteris­ tics associated with the presence of individual plant species or specific plant associations. Later investigators explored in more detail the relationship of soil characteristics to the distribution of specific plant communities (Billings 1950, Gates et a1. 1956). Rangeland inventory techniques developed by land adminis­ tration and conservation agencies identified and delineated vegetation on maps by "range types." Range types were de­ termined according to the plant species or groups of species that were either most abundant or provided a characteristic aspect to the area. Each kind of rangeland was classified in 1 of 18 major range types (Stoddart and Smith 1943). Graz­ ing values for each range type were calculated according to the estimated density or thickness of the plant stand, the estimated species composition, and the estimated grazing value or palatability rating assigned to each species. Minimal consideration was given to edaphic characteristics,

climatic influences, or the successional status of plant com­ munities. This kind of vegetation inventory was somewhat useful for estimating livestock stocking rates and for deter­ mining the best season for grazing, but it was inndequate for predicting responses of complex rangeland plant conunu­ nities to changes in use or management. Increasing worldwide demand for agricultural products re­ quires intensive use and management of all agricultural land, including that used primarily to produce native forage plants for domestic livestock and wildlife. Moreover, almost all rangelands have important uses in addition to forage production. Most are important as watersheds, many for outdoor recreation, some as natural areas, and some as the habitat of threatened or endangered plants and animals. Optimum multiple use of rangelands to meet present and future needs requires extensive knowledge of their capabili­ ties and limitations. Basic knowledge of the dynamics of native plant communities and the characteristics and prop­ erties of associated soils is fundamental in applying eco­ logical principles to evaluation and management of the rangeland resource (Humphrey 1947, Renner 1943, Dykster­ huis 1949, 1952, 1958, Parker 1954, Shiflet 1973). Knowledge of present and potential plant cover and its effect on runoff, streamflow, and erosion is essential in planning , for watershed protection and flood prevention. In many places the value of rangelands for watershed transcends that for any other single USI::. More sophisticated resource information is needed for plan­ ning rangeland use and management by individuals and groups concerned with grazing and wildlife habitat; for river basin studies; for watershed planning and flood prevention projects; and for land use ph; ;'lning by county, multicounty, state, and regional planning groups and units of government. Basic resource inform§,tion is also necessary as a benchmark

1

for analyzing ecosystems and monitoring resources; for eval­ uating recreation potential, wildlife habitat, and natural areas; and for protecting threatened or endangered organ­ isms. Expanded ecological understanding permits more meaningful interpretations of soil surveys and coordination of such interpretations within and between states. Principles of plant ecology and soil science are reflected in the range site and condition concept of rangeland resource inventory used by the Soil Conservation Service (SCS) of the U.S. Department of Agriculture (Dyksterhuis 1958, Shiflet 1973). A range site is defined as a distinctive kind of rangeland that differs from other kinds of rangeland in its ability to produce a characteristic natural plant community. A range site is the product of all environmental factors responsible for its de­ velopment. It can support a native plant community typified by an association of species that differs from the potential natural plant communities of other range sites in the kind or proportion of species or in total production (SCS 1976). The native plant community occupying a range site in the absence of abnormal disturbance and physical site deterio­ ration is the climax plant community for that site (original, potential, and natural are regarded as synonyms for climax in this pUblication). A climax plant community is the com­ munity best adapted to the unique combination of environ­ mental factors of the site. Disturbances such as drought, fire, grazing by native fauna, or insect and disease damage are recognized as natural factors in the development of native plant communities. Clements (1934) stated: "The natural plant communities are not merely the best integrators of the effects of climate and soil, but automatically they are also by far the best judges of these two complexes in terms of plant production." Rangelands of the Intermountain West have a relatively long history of grazing use. Although the exact date that domestic livestock were introduced is not known, local Indi­ ans were probably using horses by the end of the 17th cen­ tury (Roe 1955). Grazing use was undoubtedly light and sporadic, however, until permanent settlements were estab­ lished in and near the SaltLake Valley of Utah in 1847. After settlement, cattle, horses, and sheep were introduced and increased rapidly. Most of the rangeland accessible to exist­ ing sources of livestock water was fully stocked by 1880 (Walker 1964). Domestic livestock grazed native vegetation more inten­ sively and continuously than did indigenous grazing ani­ mals. Continued close and selective grazing of preferred plant species reduced the abundance of palatable grasses and forbs and generally the total production of vegetation. 2

Because of continued improper grazing, palatable forage plants were partly replaced by plants of lower grazing value. Many of the less useful plants were woody species. Woody plants have increased on sites where they normally were sparse and have encroached un other sites where they did not grow originally (Cottam 1947). Grazing abuse, repeated burning, cultivation, and other abnormal disturbances have destroyed or extensively modified climax plant communities on many rangeland are3S (McArdle et al. 1936). If all rangelands were now in climax status, range sites could be recognized and mapped entirely according to the plant community they support. The absence of climax vsgetation, however, requires that more permanent features of the site, such as soil, climate, and topography, be used as range site indicators. Again, if representative areas of each significant climax plant community could be found, it would be rela­ tively easy to project the characteristics of those commu­ nities onto all other areas having similar soils and climate. Remnants of climax vegetation are scarce in most western rangeland areas. Thus, approximation of the probable plant­ community potential for many sites has necessarily been empirical. If significant relationships between plant communities, soils, and climatic regimes can be established through study of existing relicts of climax vegetation, we should be able to approximate plant community characteristics through in­ terpolation and extrapolation for sites on which no represen­ tative climax plant community has been found.

Objectives and Justification The Soil Survey Investigations and Plant Science Divisions, Soil Conservation Service, began a study in 1957 to de­ termine the range of soil, climate, and vegetation charac­ teristics consistently associated under natural (climax or near-climax) conditions. Comprehensive study of climax plant communities and of the interrelationships of individual plant species within the communities was needed to reach this objective. Emphasis wall on identifying the responses of plant species and com­ munities to various combinations of contrasting, compensat­ ing, and fluctuating physical environmental factors. Another objective was to test existing study techniques and to modify them or develop new techniques and methodology as needed. A better understanding of relationships between soil, cli­ mate, and climax plant communities would identify factors important to the wise use and management of rangeland resources and would facilitate inte·rpretation of soil surveys for appropriate alternative uses of rangeland.

Scope and General Description of the Study Region Studies were confined to those parts of northern Utah, northeastern Nevada, southern Idaho, and west-central Wyoming that are generally characterized by Entisols, Aridisols, and MolHsols, and by sagebrush-bluebunch whiiatgrass-Sandberg bluegrass-Idaho fescue associations. The study location map (fig. 1) was adapted from Land Re­ sO!tTce Regions and Major Land Resaurce Areas of the United States (Austin 1965). Project study locations were all within the Western Range and Irrigated Region and the North­ western Wheat and Range Region, as shown on the map. Studies were conducted in seven major land-resource areas (MLRA's). Thirty-two project study locations within these MLRA's are idfmtified by circled numbers on the map. Sev­ eral of the numbered study locations contain more than one study site. A generalized map of the study region, showing the distribution of principal kinds of soils by order, suborder, and great group, is included as appendix exhibit 1.

The Snake River Plains area (MLRA 11) is about 565 km (350 mi) long by 80 to 130 km (50 to 80 mi) wide and is the most prominent physiographic feature of southern Idaho (Ross and Savage 1967). The resource area extends in a rough crescent along the Snake River almost the full width of the state. Geologically, this area is a structural depression that has filted with Pliocene and more recent basalts. Elevation ranges from 610 m (2,000 ft) in the west to nearly 1,680 m (5,500 it) in the east. The western third of the area consists of broad smooth ter­ races, fans, and occasional lava flows. The eastern two-thirds is a relatively level plain broken by isolated buttes, cinder cones, and low broad basalt mounds and ridges. All except recent lava flows have been covered by a loess mantle of var­ iable depth. Basaltic materials are relatively unweathered, and loess is the principal soil material. Basaltic materials are mixed with loess in some local areas. Prominent soils are Haplargids, Durargids, Durorthids, Cal­ ciorthids, Torriorthents, and aridic intergrades to Haplo­ xerolls and Argixerolls.

Physiography, Geolclgy, Soils, and Land Use

The study region is generally characterized by numerous high but narrow mountain ranges oriented north-south and separated by semidesert valleys, plains, tablelands, and occasional river valleys and canyons. A brief description of each major land-resource area in which studies were con­ ducted follows. The Upper Snake River Lava Plains and Hills area (MLRA 1O)! lies in the we.st-central part of Idaho between the Snake River Plains to the south and the steeper mountains of cen­ tral Idaho to the: north. It includes nearly level, sloping, and undulating fan deposits adjacent to steeper hills and moun­ tains. This area receives more precipitation than the Snake River Plains area. Most streams are deeply entrenched. El­ evation ranges from about 610 m to more than 1,980 m (2,000 to 6,500 it). Soils !d\re generally darker, contain more organic matter, and are more productive than soils of the Snake River Plains. Soil parent materials are strongly influenced in the western part of the area by the Payette and Columbia River Basalt formations, in the central part by the Idaho Batholith (gran­ ites), and in the east by carboniferous sedimentary rocks and Challis volcanic material. Some loess is mixed throughout, especially in the central and eastern parts of the area (Ross and Savs\ge 19(7). Prominent soils are Argixerolls, Hap­ loxerolls, Xerorthents, and Xeralfs. About '(5 percent of the area is rangeland, 20 percent is forested, ;and 5 percent is irrigated cropland. I MLRA numbers correspond to major land-resource area num­ bers on map (fig. 1).

About 65 percent of the area is rangeland; 30 percent, irri­ gated cropland; and 2 to 3 percent, nonirrigated cropland. A small percentage is covered by raw lava and has no agricul­ tural use. The Eastern Idaho Plateau area (MLRA 13) is located in the southeastern corner of Idaho. Elevation ranges from about 1,370 m (4,500 ft) in the lower valleys to mountain crests more than 3,050 m (10,000 ft). Rugged mountain ranges sep­ arate the plateaus and valleys. The plateaus are mostly less than 1,980 m (6,500 ft) in elevation. The plateaus are thickly mantled with loess. Mixed alluvium and lacustrine deposits fill some level valleys and basins. Mesozoic and Paleozoic sedimentary rock formations were a major source of soil parent materials (Ross and Savage 1967, Hardy and Williams 1953). Soils in this resource area are generally higher in organic matter, darker, and more productive than soilg in the Snake River Plain, immediately to the west. Prominent soils are Haploxerolls, Argixerolls, Xerorthents, Calcixero\ls, Xerofiuvents, and a few Xeralfs. About 50 percent of the area is rangeland, 25 percent is in non irrigated crops, 15 percent is woodland, and 10 percent is in irrigated crops. That part of the Owyhee High Plateau are.a (MLRA 25) in­ cluded in the study region lies in the northeast quarter of Nevada and in adjacent extreme southwestern Idaho. Broad alluvial valleys, basins, and high plateaus are separated by numerous st,eep, rugged, narl'OW mountains orient,ed north 3

Major

Land-R~.ource

10 II 13 25

Upper Snake River Lava Plain. and Hill.

Areas

Snake River Plain.

E•• tern Idaho, Plateaus Owyhee High Plateau

Great Salt Lake Area 28 Horthl' tn Intermountain Desert ic Baa1na 32 33 Hountains Semiarid

Rocky

Project Study Locations

1. 2. 3. 4. 5. 6. 7. B. 9. 10. 11. 12. 13. 14. 15. 16. 17. lB.

Council Midvale SUlllllit Paddock Valley Reservoir Black Canyon Dam Dry Farm Paul Little Crater Kipuka \Jeston Reservoir Welton Riverdale Thatcher IIorgan Pa.ture Kipuk. Kettle Butte Kipuka Caray Kipuka Dubois Fairfield Owyhee White'. Valley Blue Spring. Hanse I Valley

':'. '.

. .' ,

. '"

,-.

.

I

"-'""

.

.~\

..... 25 ~

..

\"

,",.-­

....

28

:I.' ,'-.....

.....

WESTERN RANGE AND IRRIGATED REGION

.

'. X.

E

V

A

.....

D

A

~

WESTERN RANGE

•

AND IRRIGATED

••..··..··· ••~:p.J.Q~

.. .'. :..i : . , \

.

-.','

Figure I.-Land resource regions, major land-resource areas, and project study locations.

4

21. 22. 23. 24. 25. 26. 27. 2B. 29. 30. 31. 32.

Cedar Spring. Rattle.n.ke P•• I Lookout Pa•• Provo C~-:1yon Dinner Station Barton Ranch Fmigrant Paa. Table lIountain Wind River Owl Creek Mountain. North Thermopolb Butte Red Canyon GIDe Refuge

and south. Elevation ranges from about 1,370 m (4,500 ft) in the lower valleys to more than 3,050 m (10,000 ft) in the mountains. Soils throughout the area are strongly influenced by silicic volcanic parent materials. The Miocene Humboldt formation (sandstone, shale, mudstone, limestone, conglomerate, ash, and tuff) is also an important source of soil parent materials. Mountain ranges are dominantly Tertiary volcanic and un~ differentiated Paleozoic sedimentary rock (Sharp 1939). Soils of the high plateaus and mountains include Hap~ loxerolls, Argixerolls, Xerorthents, and Xeralfs. Soils in the southern basins and valleys include Durargids, Durorthids, and Calciorthids. Except for very small, widely scattered tracts of cropland, this resource area is rangeland. The Great Salt Lake area (MLRA 28) includes roughly the western third of Utah, west of the Wasatch Plateau, and a large part of central and north~central Nevada. The area contains a series of broad, nearly level valleys and basins alternating with steep, rugged mountains oriented north and south. The valleys occur at different elevations and are gen~ erally bordered by long, gently sloping alluvial fans. Eleva~ tion ranges from about 1,220 m (4,000 ft) in the lower valleys to nearly 3,355 m (11,000 ft) in the mountains.

The parts of the Northern Intermountain Desertic Basin area (MLRA 32) included in the study lie in the northwest quarter of Wyoming. This area is a part of the Western Range and Irrigated Land Resource Region. Physiography is characterized by broad, extensive basins. Alluvial fans from surrounding mountains coalesce, forming broad, sloping plains. Elevation ranges from about 1,370 to nearly 2,200 m (4,500 to 7,200 ft). Geologic materials are varied but are primarily from Cre­ taceous and Tertiary sedimentary formations high in silty marine and freshwater shales (USGS 1952). Shale badlands are common on the dissected outer edges of the basins. Soils include Haplargids, Torriorthents, Salorthids, Pale­ argids, and some ArgiustoHs. A small part of the area is used for producing irrigated crops, but most is rangeland. The small part of the Semiarid Rocky Mountains area (MLRA 33) included in the study lies between two tracts of MLRA 32 in west-central Wyoming. This small area is char­ acterized by narrow valleys, steep slopes, abrupt mountains, and occasional desertic basins. Paleozoic sedimentary for­ mations, ini!luding Phosphoria, Tenllleep, Amsden, Madison, Bighorn, and Chugwater, are important sources of soil par­ ent materials (USGS 1952).

Most valleys in the Nevada part of the mea are filled with materials from the Humboldt formation, and the mountains are composed mainly of Tertiary volcanic and undifferenti­ ated Paleozoic sedimentary rocks (Sharp 1939).

Soils in the area include Argiborolls and Haploborolls. Most of the area is rangeland. Small tracts in isolated valleys are cultivated and irrigated.

The Pleistocene Lake Bonneville basin is the dominant phys­ iographic feature of western Utah. Lacustrine sediments, deltas, beach terraces, and offshore bars are readily identi­ fied features of the landscape. Lake sediments are derived from a variety of sedimentary, metamorphic, and igneous rock formations. Extensively sorted delta and terrace mate­ rials often extend far beyond the mouth of major canyons. Mountain ranges are predominantly undifferentiated Meso­ zoic sedimentary material, but Tertiary volcanic and meta­ morphic geologic formations are important in some sections (Eardley and Brasher 1953, Hardy and Williams 1953, Ross and Savage 1967).

Climate

Soils in the valleys include Haplargids, Calciorthids, Na­ trargids, Salorthids, Torriorthents, and Camborthids. Soils on the Bonneville and Provo terraces and adjacent foothills in the northern part of this resource area include Haplo­ xerolls, Calciaquolls, and Argixerolls. From 75 to 90 percent of the area is National Resource Lands or National Forest. Livestock production is the major agri­ cultural enterprise. Irrigated agriculture is important along the western front of the Wasatch Mountains and in a few other small areas where irrigation water is available.

The study region has continental climate characterized by aridity, hot and dry summers, cold winters, low humidity, and wide yearly and seasonal fluctuations in precipitation and temperature (Wernestedt 1960a, 1960b). Summer temperatures above 38° C (100" F) and winter temperatures below -34 0 C (-29 0 F) have been recorded. Rapid diurnal and seasonal changes in temperature are characteristic. In summer, a diurnal range of as much as 26 C degrees (47 F degrees) is not uncommon. Mean annual temperature ranges from 6 to 11 0 C (43 to 52 0 F) and varies with differences in elevation, exposure, and latitude. The average frost-free period ranges from less than 100 days at higher elevations and in the eastern part of the study region to about 160 days in the lower and western parts. The dates of the first killing frost in the fall and the last killing frost in the spring may vary by 30 days or more from year to year. Precipitation is greatly influenced by orographic features. For the study region as a whole, annual precipitation ranges from less than 13 cm (5 in) in the driest areas to more than 76 em (30 in) in the more mesic areas. Studies were con­ 5

ducted primarily in the intermediate elevations of the re­ gions, however, and did not include areas of precipitation or temperature extremes. Mean annual precipitation at study locations ranged from about 20 to 50 cm (8 to 20 in), but annual and seasonal amounts fluctuated widely from year to year. At the Univer­ sity of Idaho Experiment Station, Aberdeen, Idaho (el­ evation 1,350 m [4,400 ft]), during the 10-year period from 1958 to 1967, annual precipitation from October 1 to Sep­ tember 30 ranged from 11.5 cm (4.5 in) in 1959-60 to almost 34.4 cm (13.5 in) in 1964-65. The mean annual precipitation was 22.6 cm (9.0 in) (table 1). Precipitation patterns for three widely separated weather stations in the study region are shown in figure 2. Snow cover varies from year to year. During some winters, soils may be continuously snow covered from mid-December to mid-March. In other years, snow cover may last for only a few days after periodic light snowfalls. Much drifting of snow results in uneven coverage. During years of early and heavy snowfall, the soil beneath the snow mantle may not freeze, so that most of the snowmelt and subsequent spring rainfall go directly into the soil. When soils are not insulated by snow, they may freeze deeply, and much of the water from late snowfall or early spring rains runs off and is lost to plants except in drainageways. Wind is common throughout the year. Wind velocities are highest during short periods in late winter and early spring. Total wind travel is greatest, however, in the summer months. Persistent summer winds accompanied by high temperature, low humidity, and sparse cloud cover result in 20 _ _ _ American Falls (33 em [13 in] avg. annual) ••••••• Council (66 em [26 in] avg. annual) ------ Lander (37 em [14.5 in] avg. annual) 15

e

~

..!g

10

D.

." .......

..

..

........

"il f

".. . . . '-

••••••• 'I~ ..... ,

5 I

'-:":"

,.' '

'0.

.-_,dO'

J

F

,

,.6./0

\ ' .... .....

...........

K

A

K

J J Konth

\

0

A

Figure 2.-Monthly and annual precipitation at Council and American Falls, Idaho, and Lander, Wyoming.

6

:

" ."~'''_-,\0 : - ­

':!,-, -0, ',....

... o

,'~<

\

s

o

N

...

D

a high evapotranspiration rate. Evaporation from free water surfaces from May through September ranges from 100 to 150 cm (40 to 60 in). At intermediate and lower elevations, monthly evaporation of more than 25 cm (10 in) is common.

. • Methods

Study Sites

Detailed studies were made only on areas where vegetation had escaped significant disturbance or areas protected long enough after disturbance for secondary plant succession to reestablish the climax plant community. Such areas are called "relicts." Weaver and Clements (1938) defined a relict as "a community or a fragment of one that has survived some important change ... relict communities indicate the operation of a compensatory or protective feature." The Glossary of Terms Used in Range Management (Kothmann 1974) defines a relict as "a remnant or fragment of a flora that remains from a former period when it was more widely distributed." Relicts were often difficult to find in the study area. As sug­ gested by Weaver and Clements (1938), a "compensatory or protective feature" must be present or disturbance would be likely. Relict areas were proteci:ed by fences, lava flows, steep escarpments, deep canyons, ledges, or other barriers that limited access by domestic livestock or were far from sources of livestock water. Some relicts were found in undisturbed margins or corners of nonirrigated croplands and some were within long-fenced highway rights-of-way. Older areas of landscape surrounded by recent lava flows, known as ki­ pukas, provided many useful relicts in southern Idaho. When an apparently protected area was located, the plant cover was studied to determine whether it represented the climax vegetation for the site. The climax plant community is not static. Dyksterhuis (1958) stated: "Interplay of popu­ lations continues in the climax, bu~ these fluctuations tend to be around an average instead of being a moving average." The degree of fluctuation in total annual production and in species composition of climax plant communities under the arid and semiarid climate of the intermountain region had not been established . Examination, study, and cataloging of several hundred pro­ spective study locations indicated that no single criterion was completely reliable for evaluating a plant community as representing the climax. Therefore, the following factors were considered before rating the climax status of each plant community:

Table I.-Maximum and 1rdnimum monthly precipitation at Aberdeen, Idaho, Jor the 10-year period 1958-67

Precipitation (cm)"

Measurement

Oct.

Nov.

Highest 5.3 3.8 Tb Lowest 0.0 Mean 1.2 1.8 Median 0.7 1.3 • Inches = centimeters X 0.394.

b Trace-less than 0.1 cm.

Dec.

Jan.

Feb.

Mar.

Apr.

May

June

July

Aug.

Sept.

Annual

9.0 0.3 2.2

3.5 0.3 1.7 1.7

2.7 0.4 1.3 1.0

2.1 0.1

5.7 0.2 2.4 2.1

6.4 0.5 3.6 3.5

13.5 0.3 3.3 2.0

3.3 0.0 1.0 0.8

6.6 0.1 1.5 0.7

3.7 T 1.5 1.5

34.4 11.5 22.6 21.8

1.1

1.1

0.9

1. Justification.-The area was examined for the presence of barriers to domestic livestock or any other obvious evi­ dence that the area had been protected.

..

2. Composition.-The relative proportions of individual species were determined and compared with the composition of similar areas. Climax plant communities in the study region usually have a greater diversity of species than un­ protected areas with similar soil and climate. The presence of species known to be highly preferred by grazing animals indicates no recent heavy grazing use. 3. Introduced species.-The area was examined for the presence of species not part of the climax plant community. The findings had to be interpreted carefully, however, be­ cause introduced species are often found in relict areas hav­ ing convincing evidence of little or no disturbance. 4. Productivity.-A climax plant community should have a large enough population to make optimum use of available site resources. The climax community is not necessarily more productive, however, than communities in which com­ position has changed. 5. Distribution of key species by size and age classes.­ Plants in the "typical" climax plant community in the study region are of uneven age. An even-aged stand of basin big sagebrush (Artemisia tridentata ssp. tridentata), for exam­ ple, indicates severe past disturbance such as fire. An uneven­ aged stand indicates a more mature and stable community. 6. Mulch.-The amount, kind, and orientation of mulch often provide evidence of past use and treatment. 7. Disturbance.-The are.a was observed for evidence of re­ cent natural disturbances such as plant diseases and fire and insect damage. Although su,ch disturbances are natural phe­ nomena, plant communities recently disturbed usually have not returned to the degree of stability characteristic of cli­ max. Evidence of chemical plant control; livestock drop­ pings, trailing, or trampling; and disturbance by vehicles or agricultural equipment was evaluated. 8. Cryptogam cover.-Relict areas appear to support a

more uniform cover of these small plants than disturbed

areas.

9. Soil surface.-The rate of soil movement or deposition was compared with the natural geologic rate for the site. 10. History.-Areas grazed moderately by domestic live­ stock were not excluded from study unless such use signifi­ cantly altered the plant community. Relict areas evaluated on the basis of the above factors were divided into the following categories: 1. Areas with no history of use or disturbance by man and surrounded by physical barriers that could be traversed by domestic livestock only with great difficulty. These were con·· sidered pristine relicts.

2. Areas on which vegetation was judged to be climax or near climax but possibly having been slightly disturbed. 3. Areas known to have been disturbed but having been protected long enough for the plant cover to return to near­ climax status. 4. Areas protected from disturbance for several years but on which the plant community appeared to lack some char­ acteristics of climax. From the many areas examined, 32 were selected for detailed study (fig. 1). These 32 areas ranged from about 1 to 80 ha (2.5 to 200 acres). Several selected areas contained two or more different plant communities on distinctly different soils. From 2 to 13 individual study sites were located within each relict area where su~h plant-community differences existed. Thus the relatively small size of the relict area minimized climate as a variable site factor and permitted comparison of plant community differences with differences in soil and topography. Plant Nomenclature

Nomenclature of vascular plants, with a few exceptions, conforms to Checklist of the VascuLar Plants of the Inter­ mauntain Re{Jicm (Holmgren and Reveal 1966). Primary ref­ erences for field plant identification were Holmgren (1942), Hitchcock (1950), Kearney and Peebles (1951), Davis (1952), Harrington (1954), Hitchcock et al. (1955), and Plummer et al. (1966). 7

Nomenclature of grasses follows Hitchcock (1950). Hitch­ cock separated the bluebunch wheatgrasses primarily on the presence or absence of divergent awns. Studies by several in­ vestigators (Tidestrom 1925, Daubenmire 1939, 1960, Passey and Hugie 1963) reveal many variations in this characteris­ tic. Some populations of bluebunch wheatgrass are uniformly awnless; others are uniformly awned, with well~developed divergent awns; and still others are intermediate, with awns shorter and straighter than those associated with typical bearded bluebunch wheatgrass. Some authors have sug­ gested that there is only one species of bluebunch wheat­ grass, with wide variations in development of awns. In this study individual spikes oi some plants produced some florets with divergent awns; some with short, straight awns; and others without awns. Awn development, however, appeared to be associated with edaphic differences. Therefore, if the majority of the bluebunch wheatgrass population was awn­ less or produced only short, straight awns, the grass was identified as beardless bluebunch wheatgrass (Agropyron in­ er-m.e). If the majority of the plants produced spikelets with well-developed divergent awns, the grass was considered to be bearded bluebunch wheatgrass (Agropyron spicatum). Nomenclature of sagebrush (Artemisia spp.) also presented a problem. Generally the nomenclature of Beetle (1960) was followed. Early in the study, morphological differences were noted among populations of big sagebrush (Artemisia triden­ tata). Some differences appeared to be strongly associated with specific soil properties, soil parent material, and minor climatic differences. Later studies by Young (1965), Beetle and Young (1965), Marchand et al. (1966), and Tisdale et al. (1969) describe ecologically significant subspecies of big sage­ brush. Visual field identification of subspecies is sometimes difficult because morphblogical differences are not always easily recognized. Studies by Young (1965) and Winward and Tisdale (1969) demonstrated the use of chromatography and fluorescent color of methanol extracts viewed under longwave ultraviolet light in separating subspecies of big sagebrush. In the spring of 1970, sagebrush samples were collected from each study site. Foliage extract samples were prepared for examination under longwave ultraviolet light according to the method described by Winward and Tisdale (1969). From the fluorescent color of the methanol extracts and the subtle morphological differences described by Beetle and Young (1965), big sagebrush, initially regarded as a single species, was separated into three subspecies: basin big sagebrush (Artemisia tride'lllata ssp. tridentata), mountain big sage­ brush CA. tridentala ssp. vaseyana), and Wyoming big sage­ brush CA. tridentata ssp. wyomingensis). An inventory of plant species was made at each study site. A list of scientific and common names of species is included as appendix exhibit 2.

8

Study Site Delineation

Each location was examined in detail to ensure maximum uniformity of soil and vegetation within the specific area included in a single study site. Thus, the homogeneity of the soil and vegetation determined the size and shape of each study site. A detailed description of each undisturbed study site was prepared. Black-and-white and color photographs were taken to document features of the landscape, vegeta­ tion, and soil.

. 1

Vegetation Studies

Productivity data were obtained once during the growing season when seeds of the most common grasses-bearaed bluebunch wheatgrass, beardless bluebunch wheatgrass, Idaho fescue (Festuca idahoensis), or Thurber needlegrass (Stipa thurberiana}-had reached the dough stage but were not dry enough to shatter. Depending on elevation, seasonal precipitation, and temperature, this stage was reached be­ tween mid-June and mid-JUly. Productivity data collected at that time are not the most representative for all species within the plant community. Early-maturing forbs and grasses, especially annuals, are often dry, brittle, and dif­ ficult to harvest and identify. Also, deep-rooted shrubs do not always reach their maximum seasonal growth by that time. This stage of growth, however, was considered to give the best representation of production th8.t could be obtained by a single harvest. Moreover, since all determinations were made at about the same stage of plant growth each year on all study sites, these data are assumed to represent annual production. Total productivity was estimated by the "weight unit"

method described in the National Range Handbook, section

604.2 (SCS 1976). English units of weight and measurement

used in collecting field data have been converted to metric

equivalents.

During the first year of study three clustered 0.89-m 2 (9.6-ft2 ) plots were located at a central point in each study site (fig. 3). The current season's growth of each plant species was esti­ mated, and the total weight was recorded in grams for each of the three plots. Plants that could not be positively identi­ fied were collected for later identification, or early-maturing species were grouped as "other forbs" or "other annuals." The weight of plant litter in each plot was estimated. Twenty additional plots of the same size were randomly located within the boundaries of the study site. The weight of indi­ vidual species and of litter on these 20 plots was estimated. After all weight estimates were made, herbaceous plants in the three central plots were clipped at ground level (fig. 4), and the harvested material of each species from each plot was placed in a separate labeled paper bag. The current season's growth of each woody plant species, including

;

Figure S.-Three clustered O.89-m2 (9.6-ff) plots near central point of a study site.

Figure 5.-Paper bags suspended from U-shaped iron rod, 6 mm (% in) in diameter, with ends pushed into ground. Thus suspended, bags remain open and se­ cure even in moderate wind.

leaves, twigs, inflorescences, and fruit when present, was also collected and bagged. All litter that could be readily picked up was collected. A holding device for the paper bags made harvesting easier (fig. 5). Harvested material and litter were weighed immediately.

cies in the 20 random plots were converted to air-dry weights by applying the same percentage of shrinkage recorded for the harvested material. Total annual production for the study site was expressed as the average air-dry weight of all species in the 20 plots, converted to pounds per acre by the following formula:

The estimated weights by species in the 20 random plots were adjusted according to the average difference between estimated and actual weight of the species on the three har­ vested plots.

(Frischknecht and Plummer 1949).

Harvested material was retained until thoroughly air dry and then reweighed. The adjusted estimated weights by spe-

Pounds per acre were converted to kilograms per hectare by the following conversion:

pounds per acre

=

total weight of 20 plots in grams 2

kilograms per hectare

=

pounds per acre X 1.12.

Species composition was expressed as the percentage of total annual production contributed by each species. Frequency was expressed as the percentage of all plots in which a spe­ cies occurred. The following characteristics were estimated for each plot: (1) percentage of surface covered by plants, (2) percentage of surface covered by rock or stones, (3) percentage of surface that was bare soil, (4) basal area of all plants, and (5) rating of the cryptogam cover (as good, fair, or poor) relative to the amount and distribution normal for the site . .\t each location, the size, height, apparent vigor, and habit of growth were recorded for all important plant species. Presence of rhizomes or stolons, presence of dead plant cen­ ters, number and kinds of seedlings, and other character­ istics of the vegetation were noted. Figure 4.-Current season's growth of herba­ ceous vegetation clipped to ground level.

The number of individual plants of each woody species by maturity class (dead, partly dead, mature, immature, seed­ ling) was recorded by classifying and counting all shrubs on 9

a belt transect 61 by 1.5 m (200 by 5 ft) that intersected the three central plots. The age of representative shrubs on each study site was determined by cutting stems and counting annual growth rings. Production studies were repeated annually for 10 years on 17 representative study sites to determine the extent of annual and periodic fluctuations in production and species composi­ tion. These sites are referred to as repeat study sites. The methods used in the first year of the study were sligh tly mod­ ified. Production by species was estimated on 20 randomly placed 0.89-m2 (9.6-fe) plots. All plants on three of these plots were then harvested by species and weighed. The actual weights, fresh and air dry, were used as a basis for adjusting the estimates and determining total annual production. In the few places where random plot selection included a pre­ viously harvested plot, an alternate plot was selected. Throughout, differences in rounding and English-metric conversion procedures may cause data totals to appear off by one unit. Soils

During the first year of study at each site, a soil pit was dug within the boundaries of the three clustered clipped plots. Pits were excavated by hand tools to bedrock or to a point below any indication of soil development (fig. 6). Pits were 1 to 1.2 m (3 to 4 ft) wide and 2.5 to 4.5 m (8 to 15 ft) long. Pit dimensions decreased with increasing depth (fig. '6). Each soil profile was examined, and a detailed description was prepared according to provisions of the Soil Survey Man­ ual (Soil Survey Staff 1951). Soil classification followed Soil Taxonomy (Soil Survey Staff 1975). Soil series names were based on correlation information available as of 1969. Some of the soil series names may have changed as a result of latC!r correlations.

Figure 6.-Soil pit excavated to bedrock or below

indication of soil development. Abela

gravelly loam, loamy-skeletal, mixed,

mesic Aridic Calcixerolls (scale in

feet).

Cracking patterns with or without segregated coarse par­ ticles, plant pedestalling, surface soil movement, and other significant soil surface features were recorded.

tory at Lincoln, Nebraska, and those from Utah were ana­ lyzed by the Soil Survey Laboratory, Utah State University, Logan, Utah.

Depth, size, kind, and extent of root systems of significant plant species were observed and recorded. The effects of coarse fragments, soil structure, and restricting horizons or layers on root growth characteristics were noted.

Bulk density was determined by the clod method and by the 5-cm (2-in)-diameter undisturbed core method at the project headquarters in Salt Lake City, Utah.

Records were also kept of the number, size, kind, and lo­ cation of soil fauna seen while excavating the soil pit and preparing soil profile descriptions. Each soil profile was pho­ tographed in color and in black and white. Samples of selected soils were analyzed according to Soil Survey Laboratory Methods and Procedures for Collecting Soil Samples (Soil Conservation Service 1972). Samples from Idaho and Nevada were analyzed at the Soil Survey Labora10

Soil moisture at the 17 repeat study sites was determined at the beginning of the growing season (April 1) and when vegetation was harvested. The moisture content of each soil horizon was determined gravimetrically. During the first year of soil moisture study, only one sample was collected from each horizon. After acquisition of an electric oven in 1960, three moisture samples were collected annually from each horizon. Samples were oven dried at 105 0 C (221 0 F) for 48 hours before being reweighed. T,he water content of each soil horizon was calculated from the moisture and bulk den­

sity data. Soil moisture determinations were made for 8 con­ secutive years on some of the 17 repeat study sites and for 9 consecutive years on the others.

Climate

Climatological data from all weather-recording stations in the general vicinity of each study site were obtained ft'om monthly and annual U.S. Weather Service summaries. Most of the study sites are in isolated areas, and many are some distance from the nearest weather station. Distance and differences in elevation, geographic position, and exposure limited the direct application of weather station data to many study sites. Standard 20.3-cm (8-in) rain gages were installed at seven key study locations to supplement precip­ itation data from weather stations. Gages were mounted on steel posts with the gage opening 76 cm (30 in) above the ground surface. A spring scale was calibrated to indicate the amount of precipitation in inches when the gage and its con­ tents were weighed. Precipitation was measured and re­ corded about April 1, July 1, and October 1 of each year. So that water collected would not freeze and evaporate, calcium chloride and oil were placed in the gages. Gages were emp­ tied and cleaned each year after the October measurement. Rain gages were read periodically for 8 consecutive years at some study locations and for 9 years at others. Precipitation patterns at established weather stations were compared with rain gage records at the repeat study locations. Where patterns were similar, the weather station data were inter­ polated to represent the study location.

Data Analysis

A computer was used to analyze the large volume of data accumulated from 85 study sites between 1958 and 1969. Be­ cause it was desirable to reduce the number of plant species to fewer than the 270 recorded in the studies, we used a prevalence index modified from Curtis and McIntosh (1950) to select constant dominant species: PI (prevalence index) = PF X Pc, where p = percent X 100, F = frequency, and C = composition by weight. This formula could hypothetically create a PI range from 10,000.00 (p~. = 100.00, Pc = 100.00) to 0.00. For the 48 species selected, PI values ranged from 894 for bearded bluebunch wheatgrass to 0.02 for Leiberg bluegrass (Paa leibergii). The species included represent the constant dominar.cs as well as other important species (table 2). Species associations are determined by the degree of inde­ pendence and joint occurrence in a set of quadrats. Coeffi­

cients that indicate association between species are widely used in studies of ecological relationship (Cole 1949, 1957, Hurlbert 19(9). Chi-square analysis is used to determine these coefficients. They are, however, dependent on quadrat size and number of samples (Hurlbert 1969). The chi-square statistic does not assume a normally distributed population, since it tests the independence between individuals. Species association groups are determined according to the probability of such associations occu:~ring strictly by chance. For example, if the computed chi-square value exceeds the tabular chi-square value (for the given degrees of freedom and desired probabil­ ity level [P]), then a high degree of association has been found. Coefficients of association were derived by chi-square anal­ ysis for each species. These association coefficients were used to group species reflecting strong associations by use of the "unweighted group method" with simple averages rather than correlation coefficients (Sokal and Sneath 1964). Plant species with the highest positive coefficients are grouped and other species are added from those remaining as the coeffi­ cients are reaveraged (fig. 7). This process can continue until all species are grouped into one "superassociation." Group­ ing can, however, be stopped at any level and was arbitrarily terminated when no individual chi-square value exceeded 1.7 (corresponding to P = 0.25). Thus, hypothetical, discrete species associations were developed as shown in figure 7. These groupings were considered most realistic. The degree of association between individual species from sev­ eral stands of vegetation can also be determined by calculat­ ing correlation coefficients. These coefficients of association can be computed from frequency data for pairs of species from a common set of plots. Such coefficients, however, are biased by species competition if only plots containing buth species of a pair are the basis for analysis; and only a small number of samples are available from which to com­ pute the statistic. For an acceptable test of association, all plots within all stands where one or both species of the pair occurred were used (Hurlbert 1969). Figure 8 is a dendro­ gram of such correlation coefficients transformed to Fisher's z value and clustered by the unweighted group method based on simple averages (Sokal and Sneath 1964). The seven asso­ ciation groups shown in figure 8 result when grouping is terminated at z = -0.2, which by subjective judgment pro­ duces the best grouping. Several points were tried before this value was selected. Through rearrangement of the data matrix, 85 study sites were treated as individual sites. Vegetational similarity be­ tween any two study sites was determined by calculating the coefficients of correlation between frequency values of plant species contained in the plant communities. The resulting coefficients were then transformed to Fisher's z values and clustered. Figure 9 shows the most meaningful cluster of

11

Table 2.-Prevalence index of key plant species included in computer analysis Plant species· Bearded bluebunch wheatgra.ls

Sandberg bluegrass Wyoming big sagebrush Beardless bluebunch wheatgrass Idaho fescue Arrowleaf balsamroot Basin big sagebrush Longleaf phlox Thurber needlegrass Cheatgrass brome Tapel'tip hawks beard Hoods phlox Douglas rabbitbrush BottIebrush squirrel tail Prairie junegrass Threetip sagebrush Tapertip onion Antelope bitterbrush Low sagebrush Loco Nineleaf lomatium Stream bank wheatgrass Needleandthread Lupine

Prevalence index

894 657 396

387 217 160 124 86 42 42

26 23 22

21 14 13 9 6 6 5 5 5 4 4

Plant species Mountain big sagebrush Western hawksbeard Oblongleaf bluebell Common yarrow Western wheatgrass Cusick bluegrass Basin wildrye Threadleaf sedge Narrowleaf pussytoes Hooker balsam root CutIeaf lomatium Beardtongue Lambstongue groundsel Wyoming threetip sagebrush Alkali sagebrush Hoary balsam root Onefiower helianthella Wyeth eriogonum MacDougal lomatium Wayside gromwell Utah juniper Black sagebrush Fringed sagebrush Leiberg bluegrass

• Scientific plant names are shown in appendix exhibit 2.

study sites at z = 0.250. Termination of grouping at this point clustered 79 sites into six associations. Six study sites were significantly different and were not included in any of the hypothetical associat!ons.

Prevalence index 4

3

3

2

2

1 1 1 1

1

1

1

1

1

0.6 0.4 0.4

0.4 0.4 0.2

0.1 0.1 0.04 0.02

Results and Discussion

Vegetation Groups

The effect of various environmental factors on total an­ nual production and production of individual plant species was determined through scattergrams and simple linear regressions. The production consistency or dependability of plant species was evaluated by determining the percent standard devi­ ation of the mean production on each study site and aver­ aging as follows: Average percent deviation of the mean= IT.itet 1OO XIII. I

+ IT.it.2100 X.lte 2 '

N

etc •

'

v/here

= standard deviation of the mean, S( = mean of plant species production, N = number of sites on which the species occurs. IT

12

The hypothetical species associations identified through the chi-square test of independence and frequency correlation (fig. 7 and 8, respectively) are not definitive, but they are useful in various ways. Some of the hypothetical associations appear valid, but others seem unrealistic. For example, con­ tingency association groups 1, 3, 4, 5, 7, and 8 (fig. 7) appear reasonable, even though group. 5 contains two subspecies of big sagebrush. Species. in group 2 occur frequently together in the field but usually are associated with the other plant association groups. Species in group 2 have wide growth adaptations and occur in plant communities on many study sites. Hypothetical plant associations derived by correlation coefficients are generally similar to those derived by chi­ square analysis. For example, groups 1 and 2 in figure 8 are similar to groups 1 and 2 in figure 7 except for the presence

AGSP.!J SlHY

I I

5TTH2

ARTRI,'"

,

2

I----!

CROC LOMA2 POSE PHL02 ALAC4 O.Annua 12/

f----J

~

BRTE AGRI

rI

CHVIB FEID

:3

~lI

KOCR CAfl ARTR4 ELCI2 LUPIN

1--

MEOB

1

SElS:! O.Grass e~2J POLE

4

~,

BAllO ARARS ANST2

AGtN ACMlL

~I

LIRU4

ARTRV HEUN ARTRT'"

5

PENST PLTR2 ERHE2

I I

i

LODI

poce:! !lAIN

I

I

I

ARTRR'"

J-i

AGSH

8

-

q,

LOTR2 CRAC2

7

I

~

O.Woody 1J JUNIP !lA$A)

6

I

ARFR4 PHHO ASTRA O. Forbs _ 21 _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _---l

~\

STC04 ARARN 100.

90.

BO.

70.

60.

50.

40.

3C'.

20.

10.

I n.

-10.

Clustering level l/Plant symbols (rom National List of Scientific Plant Names, USDA, S011 Conservation Service,1971. See appendix exhibit 2. "'--Symbol ~entative, not in National List of Scientific Plant Names. !/lncludf

more than one species.

'Figure 7.-Plant-species association groups derived by chi-square analysis.

13

Pla,lt symbu 1

..

2

AGSp!J ARTRI-.' .... ::;IHY

CROC

AGI;\

POSE STC04 l'HHO ARFR4 STU!2 pHL02 ALAC4 ARAR.-;

LOXA2

LOJI

BRTE FEID

J-f-l I

1-t-~I

.. -

AGR~

3 !l. ::J

::l

'" '-'

!

CAFl ARTR4 ELC12

CH\'l8

KOCR POC1:3 ASTRA

-

BAT;\

4

ARTRR*

I I I

~

O.ForbsY ACNIL

f---

I

21 O.Grasses.::. LlR1:4 BASA3 p1!TR2 ERHE2

r~

~IEOB

5

~-c-

,

O.Annual::'1

ARTRV CRAC2 LOTR2 pE:\ST

'-

HEUl\

I I

ANST2 21 O.Woody­ POLE

6

7

I--

i

AGS~!

SEI:\2 LtJ1'n;

I I_

r-

I

SAHO ARAR8

ARTRT*

I

Jl'l\lp

0.5

2

I Clustering level (Fisher' s

,

o

-0.2

I

-0.5 I

~)

l/Plant symbols from National List of Scientific Plant Names, USDA, Soil Conservation Service)l971. See append.ix exhibit 2. "'--Symbol tentative, not in National List of Scientific Plant Names. l/Includes more than one species.

Figure S.-Plant-species association groups derived by frequency correlation.

14

s•.dy 51tt' 14

I-56

Id

3...00 .-00

Id

I

3-5a

I. \2-5 8

l

14

0=J-

Id .-59

ld 14-58

14 15-5

e

I-~9

10



I.

7-59

Id I.

... ,5a

5-58

i. 13-5e Id 11-5 E

U.

I~

14 Id

5-59

9-6:)

Id 7-58

I. 9-5e I. !I-56

2

I

I

~

Id 1:;1 .. 50

Id 8·S6

I

I

I

I

I

I

I

I I­ ~I

17-~

10

\e... se.

10

I. 17-'. N ... A.. 5t;

N.5-5. Id Id

6-59

8-60

II-59

13-59

14-59

8-59

9-59

6-60

I.

Id Id Id Id I.

~

Id 10-5; Id 1-0.0

Id

1-6.

I.e

4-44

leS

5-oA

I. 14 ""'1

..

3 4

:J--I

-

7-64

1-60

I

\-6\

W, 5..0 1

I

Wy 2-65

Id 7-59

N..,. 2-59

~ r-l

N.I-6.)

N. 2-60

I.

2-58

14

1-60

Wy 1-01>

Id Id Id U,

\0-1>0

11-60

12-60

5-60

I. IJ-6C UI .-56 U. \-56

~

U' .-.58

U, 2-59

Ur 4-60

~

UI 7-58

U. 3-5" Ur 4-59

U. 5-58

UI 3-60

V, 2-60

U, I-59

Ut Ut 10 N.

I­

I

I

r-­ f­

::;:=J

6-60

7-IJ(J

3-68

I-59

I. 2-60

>-

10 3-6A

I. I.-58

I. Id

w., Wy

"­

1

w, w, 7-61

1-65

N. 3-60

Id 1-66

N ... 3-5«;

5

t­

H-­

5-60

3-5.

3-4t '-61

lJSi.nah 'Stud.., 'Situ.•

ClOt-

0.25

0.5

1.5 Cluster1n, level

(n,"'.!I'"

-0.5

5,)

ItQuped.

S~boh indicat' code. nu&'oer And location of each study site.

[d - ldaho Ut • Ut.ah

.Nil .' Nevoid .. Wf • Wyomini

lh~ f1rsr "One or tVQ di. 6 \t.S fon~"'tn, d.es~&n.tt.Qn q( s,.. Ce represent the ..quenee 1n 'Jhu!h the study .situ "'.re first studied.

'the hst

tl"lC

di.gitl. tndlc:,ate: the yeou 1n which the initial study

"'015

made, !~e.,

)8 • 19)8 bl • 1961

etc. For example:

10 10-S9 i"dlc,atu that this was the leth site studied in Id .. ho dur1ng

19n.

Figure 9.-Study-site association groups c!1lrived by plant-species frequency correlation.

15

of fringed sagebrush (Artemisia Jrigida) and black sage­ brush (Artemisia arOust.> ;.,e:>. oSu:>

:::2-

c;~]-

0;) ..........

• . "'0

m~

• e:>. mo

> .

.~ &

.Srj ;.e:>.

p::~

E-. .. ~ ~_ '" Ctl ~;.r:.l

0tudy site )io. IO 9-5H on the Carer Kipuka in Idaho. Bancroft silt loam, moderatclr dt,l'p o\W bedrock variant. A member of the fine-siltr, mixed, frigid family of Calcic Ar­ gj:.:l'f()lh; (~('all' in feet.) I Ril-{ht) ~llbgrollp VlI-A vegetation on Bancroft soil. Threctip sagebrush is the dominant woody plant Idaho fescue, bearded blu('bunch wheatl-{rass, Sandberg bluegrass, and a variety of Corbs characterize this plant community.

Butte Kipuka study location was between production on Brunt silt loam and the April 1 to June :30 precipitation. This relationship did not exist on the adjacent Pancheri silt loam.

By US(I of simpl(l linear regrl'ssions and scattergrams, total annual production for each year was compared with total annual precipitation and with precipitation for selected peri­ 1111-1 dUring the same years. There Was a positive relationship bl'tWt'en production and annual precipitation as well as pre­ (,lpitntion during October through March, and April through JUOl'. Although these relationships were positive, they were tOil broad to provide precise indices to plant communily Production. 30

The weak correlations (table 6), the inconsistent relation­ ships between production and precipitation (table 8), and the broadness of relationships obtained with rain-gage records may result from one or a combination of factors. Among those factors are: n) weather station data, even when ad­ justed, do not represent precipitation at study locations; (2) periodic measurement of precipitation dor~s not reveal the influence of precipitation during short but critical times; (3) climax plant communities within the study region respond differently to the amount and distribution of precipitation on different soils; (4) data collected are too few to test exist­ ing relationships accurately; and (5) total production and production of individual species in climax plant communities are inherently erratic enough to preclude the development of precis(' production indices from precipitation data alone.

Table

6.-Coe~.ents

of correiatia1l between adjusted weather-statian precipitatian recards and lO-year total production fram 17 study sites

Average precipitation Study location and soil unit representing individual study sites

Annual Oct. 1Sept. 30

Oct. 1Mar. 31

Oct. 1June 30

Apr. 1June 30

Carey Kipuka Hoelzle sil", deep variant Goodington sil Clegg sil (19 pct N slope) Bancroft gil, mod. deep over bedrock variant

0.386 0.278 0.296 0.027

0.067 0.110 -0.271 0.083

-0.079 -0.363 -0.149 -0.305

-0.178 -0.202 0.013 0.187

Little Crater Kipuka Waycup ex. st. sil, noncalcareous variant b Roseworth sil (I9 pet N slope) Trevino ex. st. sil (11 pet S slope) Neeley sil, mod. deep over bedrock variant Neeley sil, deep over bedrock variant

0.381 0.355 0.581 0.548 0.235

0.407 -0.249 0.458 0.213 -0.257

-0.255 -0.736** -0.096 -0.240 -0.550

0.036 -0.504 -0.217 -0.269 -0.352

Morgan Pasture Kipuka Newdale sil

0.413

0.177

-0.327

-0.400

Hansel Valley Abela gl (6 pct NW slope) Abela gt (13 pet W slope) Pornat I (13 pet W slope)

0.441 0.507 0.341

-0.080 -0.174 0.062

0.387 0.187 -0.215

0.378 0.325 0.051

Rattlesnake Pass Gemson sic1, thick surface variant" 0.473 0.282 ~ Si/Plificant at 0.05 probability level. .. Significant at om probability level. "Texture symbols from Soil Survey };[unual, USDA Agric. Handb. 18, 1951. p. 139. mod. b 15 pet S slope. t 10 pet E slope.

-0.631"

=

moderately, ex.

-0.595

=

extremely, st.

=

stony.

Temperature and moisture ultimately control all biological processes in the soil and are important soil characteristics (Smith et aL 1964). At a soil. temperature of 0° C (32° F), the root systems of most herbaceous plants stop functioning. Takeuchi and Hosegawa (lS58) and Wilkinson (1967) ob­ served that soil temperatures below 6 to 7° C (43 to 45° F) acted as a "temperature barrier" to penetration of cereal roots.. As deeper soil horizons warmed to 6 to 7° C (43 to 45° F), root systems continued downward growth. The growth I)f root systems of perennial plants may be expected to function somewhat similarly.

mean annual temperature for each soil was computed (table 9). Mean temperature ranged from 7.5° C (46° F) on Pancheri silt loam in the Kettle Butte Kipuka study location to 10° C (50° F) on Waycup extremely stony silt loam, non­ calcareous variant, on a 15 percent south slope in the Little Crater Kipuka study location. Mean annual temperature is lower in soils on north slopes than in soils on nearly level areas or south-facing slopes. Thi3 mean annual temperature of Roseworth silt loam, 19 percent north slope, was almost 2 C degrees (3.5 F degrees) lower than that on the south­ facing Waycup soil, although both soils occur within a rela­ tively small area. Mean summer temperature (July) was almost 4 C degrees (7 F degrees) lower on the Roseworth soil.

Temperature at a depth of 61 em (24 in) was recorded for eight soils during January, April, July, and October, and the

The influence of degree and direction of slope on vegetation is difficult to evaluate because these environmental factors

Temperature

...

Table 7,-Averu{1e annual precipitatian and awru(}e precipitatian for selected periaris frarnrain-ga(}e record.5 at six study locatians, 1961-69 Average precipitation (cm)" Study location

•

Carey Kipuka Little Crater Kipuka Morgan Pasture Kipuka Kettle Butte Kip\lka Hansel Valley Rattlesnake Pass " Inches - centimeters X 0.394,

Years of record 1951-1968 1961-1968 1961-1968 1961-1969 1961-1968 1961-1968

Annual 35 34 29 28 33 40

Oct. 1June 30

Oct. 1Mar. 31

Apr. 1June 30

32 29 24 23 27

21 21 14 13 16 23

10

34

8 10 9

11 11

31

Table 8.-Coefficients of correlation between total annual production and periods of precipitatimt for eight selected soils Average precipitation from rain gages Study location and soil unit Carey Kipuka Goodington silo Clegg sil (19 pct N slope) B:incroft sil, mod. deep over bedrock variant Little Crater Kipuka Trevino ex. st. sil Roseworth sil (19 pet N slope) Neeley sil, deep over bedrock variant Kettle Butte Kipuka Brunt sil, heavy subsoil variant Pancheri sil • Significant at 0.05 probability level.

•• Significant at 0.01 probability level.

"Texture symbols are from Soil Survey Manual, USDA

Annual

Oct. 1-

Sept. 30

Oct. 1June 30

Oct. 1-

Mar. 31

0.764· 0.584 0.778·

0.722· 0.321 0.562

0.326 0.0 0.259

0.577 0.0 0.620

0.0 0.272 0.0

0.0 0.0 0.363

0.0 0.0 0.0

0.976·· 0.955·· 0.796··

0.327 0.0

0.214 0.0

0.0 0.0

0.715· 0.0

Apr. 1June 30

Agric. Handb. 18, 1951. mod. = moderately, ex. = extremely, st. = stony.

cannot be isolated easily. In the Little Crater Kipuka study location, Trevino extremely stony silt loam occurs 011 both north- and south-facing slopes. Plant communities on both exposures are similar. Over a 10-year period, production on the south-facing slope averaged 8 percent more grasses, 2 percent more annuals, 6 percent fewer forbs, and 4 percent fewer shrubs than that on the north-facing slope. Average total annual production during that period was 103 kg/ha (S2Ib/ac,e) greater on the north-facing slope. Production of annuals, chiefly cheatgrass brome (Bromus tectorum), how­ ever, was 13 percent higher on the warmer south-facing slope. In 1966, freeze damage to growing plants was clearly evident at the Little Crater Kipuka location. Warm temperatures

during early spring resulted in unusually early plant growth, especially on the south-facing slopes. Frost occurred on May 22, 1966, when the weather station at nearby Aberdeen, Idaho, recorded a temperature of -6.7 0 C (20 0 F). This un­ seasonably low temperature damaged forbs and was un­ doubtedly a factor in the low forb production that year. At the Little Crater Kipuka location, 1963 was the only year in which no freezing temperatures were recorded after April 25. This was a year of above-average forage production for most sites at that location. Mean weekly temperature and average weekly precipitation at Craters of the Moon National Monument from April 1 through June 30 in 1961 and 1962 are shown in figure 13. The mean temperatures for these years differ greatly. From the

Table 9.-Mean soil temperature at a depth of 61 em (2.4 in) Location and soil unit Carey Kipuka Clegg silt (19 pct N slope) Hoelzle sil Hansel Valley Abela gl (6 pct NW slope)

Mean temperature" (oC)b Jan.

Apr.

July

Oct.

Mean annual

0.6 0.6

3.9 3.9

15.6 16.7

10.6 11.7

7.6 8.2

2.2

6.7

15.0

12.2

9.0

Kettle Butte Kipuka Pancheri sil

0.0

3.9

16.1

10.6

7.5

Little Crater Kipuka Waycup ex. st. sil, noncalcareous variant (15 pet S slope) Roseworth sil (19 pet N slope)

0.0 0.0

6.1 4.4

19.4 15.6

13.3 12.2

10.0 8.1

Morgan Pasture Kipuka Newdale sil

16.1 10.0 5.0 1.1 Rattlesnake Pass 15.0 2.2 12.2 Gemson siel, thick surface variant (10 pct E slope) 6.7 • Based on 2 to 3 hears' data.

b Degrees F'ahren cit = (9/5)(degrees Celsius) + 32.

"Texture symbols used are from Soil Survey Manual, Agric. Handb. 18, 1951. p. 139. ex. st. = extremely stony.

32

8.1 9.0

1961­ 1962 .. •.... ··

first week in April through the middle of May, temperatures were higher in 1962 than in 1961, but after the middle of May, temperatures were lower in 1962 than in 1961. Weekly pre­ cipitation during the spring was distributed similarly in 1961 and 1962, but during late May and early June almost 8 cm (3 in) more fell in 1962 than in 1961. The Carey Kipuka study location is within the boundaries of the Craters of the Moon National Monument, and climatic values are similar. Differences in temperature and precipitation between the 1961 and 1962 growing seasons are reflected in total annual production and in the production of individual species at the Carey Kipuka location on Clegg and Bancroft soils (figs. 14 and 15, respectively). In 1962, warm spring temperatures and ample precipitation through the first week of June were responsible for unusually high production of vegetation. Growing conditions were especially favorable for Sandberg bluegrass.

30

28

26

2~

2c

..... -,

.c

c";..;

....;

Ie

"

10

? f

..

~

;:

14

...
~

u( pl.,O[1I.

Figure 14.-Total annual production and production by species on Clegg silt loam, 1959-68.

itation. Possible sources of the extra moisture include sur­ face or seepage run-on from adjacent areas, snow drifting and accumulation during the winter months, spring runoff, or soil moisture carryover from the previous growing season. When surface soils are frozen at time of snowmelt or heavy rainfall, much of the precipitation is lost through runoff (fig. 16). If stored soil moisture is to be used as an index to plant productivity, it must be determined annually by field measurement. There is no consistent relationship between soil moisture content and previous precipitation on the soils studied. Depth of soil moisture and its removal by plants were com­ pared for the Bancroft and Clegg soils in the Carey Kipuka. Amount and depth of water removed were compared on an 8-year average and for the years 1963 and1966 (fig. 17). During the 8-year period, plants removed an average of about 12 cm (4.8 in) of water from each soil. Of this amount, 8.5 cm (3.3 in) or 70 percent was removed from the upper 34

38 cm (15 in) of the Clegg soil, but only 6.1 cm (2.4 in) or 50 percent was removed from the upper 38 cm (15 in) of the Bancroft soil. During 1963, a year of high precipitation, water removal patterns were similar for both soils. Because of abundant April-thorugh-June precipitation, however, more soil water was available below a depth of 38 cm (15 in) in both soils at the end of the growing season than was available at the beginning. The year 1966 was relatively dry. Plants obtained only 46 percent of their total moisture from the upper 38 cm (15 in) of the Clegg soil; the average was 70 percent. The water removal pattern in 1966 for the Bancroft soil, however, was very similar to that of the average. Available stored soil moisture at the beginning of the 1966 growing season was 115 percent of the previous October-through-March precip­ itation for the Clegg soil and, 100 percent for the Bancroft soil. .H is obvious that the Clegg soil contained more water

_ _ _ Yrh.ho

1.500

r".cuel)

- - - - - e.-arafOd bluebunr.h "h•• ~rIUlII

Tutal .lnl1uUl yhthl

• •••••••• Slinribe,. b1 UPlCra.I'I,

Groue>,"

Harroaile.( loco • ___ _ Tapertip hawkllbt.rd

1500

1"

-.

~

1000

~

Shrubs

""0

hi

,1"0)" lJ povnd " list'...

65

67

y~'

r--r ",cre-· k'hIJrn... Ik'r h.. "ttln' x

npP"'f\I;)h .....h'h't 2' for

.l

O.R~I.

",'l.'n,lrtr n.......

u( pt.mt"4,

Figure I5.-Total annual production and production by species on Bancroft silt loam, moderately deep over bedrock variant, 1959-68.

,..

.'

than the Bancroft at the beginning of the growing season, but it is also evident that during 1966 plants on the Bancroft soil used carryover soil moisture from previous years. The amount of stored water removed from the soil during the growing season and the amount of precipitation received during the growing season were combined to determine the total amount of water used for plant production on each of the 17 repeat study sites. These calculations did not include moisture lost through surface evaporation and deep per­ colation. The average water used was then compared with the average annual production for each study site, and the amount of production per centimeter of water used was cal­ culated (table 11). These data indicate that vegetation used water less effi­ ciently on the Goodington silt loam and Brunt silt loam than on the other soils. The indicated high production of dry matter per centimeter of water on the Waycup extremely stony silt loam may well be questioned, because the presence

of coarse basalt fragments below 38 cm (15 in) made collect­ ing soil water samples difficult and may have distorted the data for that soil. The Abela gravelly loam appears to pro­ duce slightly more dry matter per centimeter of water used than do the finer textured soils. Soil

Field observations indicate that the root system functions of native plant communities are affected by textural, struc­ tural, chemical, and physical differences in soils. Soil fertil­ ity, temperature, and water-holding capacity; depth of stored water; presence of restricting soil layers; aeration; and other soil-related factors influence plant growth. Soil depth limits the distribution of some plants. Deep-rooted species, such as antelope bitterbrush, arrowleaf balsamroot, and the subspecies of big sagebrush, for example, do not thrive on shallow soils unless the soil is underlain by porous or fractured rock that permits water to accumulate and roots

35

Table 10.-Average percentage of October-March precipitatian retained in soil at beginning of growing selUlan, 1961-69 a Study location and soil unit

1961

1962

1963

1964

1965

1966

1967

1968

1969

Average

----------------------------- Pct ----------------------------

Carey Kipuka Hoelzle sil, deep variant b 49 105 78 79 71 115 122 Goodington sil 32 85 49 62 91 64 92 Clegg sil (19 pet N slope) 60 84 87 86 71 117 97 84 Bancroft sil, mod. deep over bedrock variant 43 144 74 88 80 100 91 81 Hansel Valley Abela gl (6 pet NW slope) 75 42 58 84 53 60 Abela gl (13 pet W slope) 62 43 59 78 59 72 Pomat I (13 pet W slope) 70 55 57 91 46 144 Kettle Butte Kipuka •• A Brunt sil, heavy subsoil variant 60 35 71 62 42 1J... 46 60 Pancheri sil 129 38 91 56 77 132 55 80 Little Crater Kipuka Waycup ex. st. sil, noncale.rueous subsoil variant (15 pet S slope)' 39 35 22 42 45 44 Roseworth sil (19 pct N slope) 41 23 38 28 38 90 50 Trevino ex. st. sil (11 pet S slope) 41 34 30 34 45 37 Trevino ex. at. sil (13 pet N slope) 56 37 41 36 45 51 44 Neeley sil, mod. deep over bedrock variant 46 150 85 70 102 109 100 Neeley sil, deep over bedrock variant 55 41 52 56 44 69 61 108 Morgan Pasture Kip!.lka Newdale sil 40 140 56 77 78 63 53 55 Rattlesnake Pas. Gemson sicl, thick surface variant (10 pct E slope) 50 63 63 98 103 132 125 • Available water in soil at start of growing season X 100. Precipitation October 1 through March 31 from rain-gage data.

b Texture symbols are from Soil Survey Manual, Agric. Handb. 18, 1951. p. 139. mod. = moderately, ex. st. = extremely stony.

.., '"::0

Species

o Coo

.'So c'" "'c

~E

'--0 -0._

=~"'O

q)

cE& os os'­ o"'c r:.-

.- :a...

0'"

c.> .... ;::::0 0'-

8-

rn

"'0 :>
'& .;::::'" - ...

....'"... 0

..c

0 c.>;:::: .- 0

~ 0...

..c ... ~Q,)

0 0 0

Haploxerolls

Calcixerolls

Camborthids

c.>

0

0...

'r;;

:::>'"

'"...oSbe :>

32 64 94 0 0

Tb

14 2 26 61 16 28 10 36 0 5 0 8 0 37 0 0 0 10 1 3 38 16 0 0 0 0 0

:a :a.......

c.>

:a.... ;3

c.>

:a.... ;3

..,

:ac.>

c.>

:a :a.... ...



~

25 20 0 25 0 0 0 0 0 0

c.>

0

~

~

77

32 13 5 12 0 22 43 0 15 15 8 8 12 0 0 0 15 18 0 0 28 12 0 32 0 0 0 0 0 0

c.>

c.>

CJ

~

35 50 15 40 25 0 0 0 0 0 0 0 25 0 15 0 10 0 10 0 0 0 0 0 0

27 0 0 0 0 0 0

See footnotes at end of table.

...

,.(

~

•

{.




-

Cryoborolls

Durixerolls

Palexerolls

Argixerolls

., .,:>~

..

...:

16 33 98 48 13 52 5 0 1 45 17 0 14 20 16 0 18

25 0 15 0 0 1 11 0 0 42 45 0 0 0 0 0

.,

.,

;a

;a :.a.....


am· Study No. UT 2-58 3 km north of Promontory, Utah Plant species

1958

1959

1960

1962

1961

1963

1965

1964

1966

1967

Pet Pet Pet Pet Pet Pet Pet Pel Pet Pet kg/ha b e07np. kg/ha romp. kg/ha =p. kg/ha romp. kg/ha romp. kg/ha =p. kg/ha =p. kg/ha =p. kg/ha 007nP. kg/ha =p. Grasses Beardless bluebunch wheatgrass Sandberg blueg:-ass Nevada bluegr;'.s

804 78 2

70 7

T
.

-- t--

l/Carbonate makes up 1 to 5 percent of the sands between 28 and 69 cm (11 and 27 in) and 25 to 50 percent of sands deeper than 69 em (27 in).

lu.?4

0·51

0.66

J.87

-,

2.0

oc

86.8 14.8 56.3 l3.2

6Fla Ratios to Clay8:l Gypsum

21;4 1965 1966 1967 1.968 Pet Pct Pet Pet Pet Pet Pet Pc/. Pel Pet compo ko/J/a compo kg/Ita COlllp. kg/Ita compo kg/1m compo kg/hit com1). kg/ha compo kg/ha compo kg/ha compo kg/lut compo

619 20 2

62 2

11

1

T

665 66 9 9

55 5 1

449 31 8 1

129 19 44 15 16 63

10 2 4 1 1 5

38 3 38 8 8 32

1

Forbs Arrowleaf balsam root Edible milk"elch Longleaf phlox Tapertip onion Oneflower helianthella Other forbs d

68 9 37 34 15 50

Annuals Cheatgrass brome Other annuals C

2 25

T

2

12 37

1 3

60 29 26 1

6 3 3

69 21 36

6 2 3

Woody plants Basin big sagebrush Douglas rabbitbrush Antelope bitterbrush Broom snakeweed Rubber rabbitbrush

7 1 4.

3 1 5

61 4 1

739 43 10

6D 3 1

811 15

7

72

1,082 207

49 9

1,067 5

71 T"

713 21

69 2

8 6

103 35 19

7 2 1

66 28 4

7 3

1 1 1 3

174 125 63 113 34 57

5 2 3

21 4

T

1

1,111 80

61 4

991

38

57 22 5 4 27

T

77

64 5

T

5 5 1 1 5

88 13 37 32 24 41

3 2 2 4

57 2 9 9 15 43

19 21

3 3

40 69

3 5

17 12

1 1

166 73

8 3

93 17

45 16 21

6 2 3

58 25 30

5

114 34 9

10 3 1

25 69 6

1 3

39 93

T

1

2

2

T

5

'r

3

11 4

1

64

T

32

2 12 1 2 4 2

7 1

2

T

15 88

1 5

27 38

2 2

2 7

158 29 1

15 3

71 34

4 2

180 116

12 8

T

225 24

37 2

T

4 1 T

2

T

5 T 2 T Total annual production 1,008 100 1,210 100 738 100 1,254 100 1,147 100 2,196 100 1,496 100 1,037 100 1,819 100 1,544 100 Total estimated litter' 2,024 2,027 1,421 1,475 1,294 1,220 2,387 1,783 928 1,196 a Repeat studies based on 20 random estimated plots. b Pounds per acre = kilograms per hectare X 0.891. • Trace-less than 1 percent. d Other forbs include common yarrow, pale agoseris, low pussy toes, Holboell rockcress, cra~ aster, timber milkvetch, sego lily, tdterti p hnwksbeard, Nuttall larkspur, eriogonum, prickly lettuce, wayside gromwell, nineleaf lomatium, tailcup lupine, silky lupine, oblongleaf bluebe I, nodding microseris, Wasatch bear tongue, Munro globemallow, salsify, and violet. • Other annuals include bushy bird beak.

'Total estimated litle!' for 1959 and 1960 included humic mulch.

•

.a

"

~

;.

J.

...

Exhibit 8B.-Soil profile description, Gemson silty clay loam, thick surface variant

STUDY NO.:

UT 2-59

AVERAGE ANNUAL PRECIPITATION: ELEVATION: 1,631 m (5,353 ft) MEAN ANNUAL TEMPERATURE: 8° C (46° F)

36 cm (14 in)

LOCATION: Box Elder County, Utah, 39 km (24 mi) west of Tremonton, Interstate Highway 80 N at Rattlesnake Pass. It is near the center of Sec. 3, T13N, R6W (SLM), 41 °52' N., 112°32' W. LAND FORM: Sloping and rolling upland, 10 percent east-facing slope. CLASSIFICATION: Gemson silty clay loam, thick surface variant, a member of the fine, montmorillonitic, mesic family of PACHIC ARGIXEROLLS. P ARENT MATERIAL: Loess, volcanic ash, and basalt. REMARKS: This pedon is similar to the Gemson series except that it has a deeper mollic epipedon. Gemson soils are not "Pachic." This pedon has a deep, neutral to mildly alka;,;'IP ll;,~lic epipedon, a mildly alkaline argillic horizon, and a mildly to moderately alkaline calcic horizon. Prismatic structure of the argillic horizon is tilted toward the east, nown the slope., Possibly soil creep is operating here. Bf-salt pebbles, cobbles, and stones are common below a depth of 81 cm (32 in), and basalt residuum appears to be the major source of parent material. About 44 percent of the ground surface is bare, 2 percent is covered by stone, and 54 percent is covered by vegetation, litter, or both. Bare surface soil cracks upon drying, and the cracks form a weak polygonal pattern. Polygons have weak thin platy structure and contain many vesicular pores and a few fine roots. Roots of beardless bluebunch wheatgrass are present to a depth of about 80 cm (31 in), and big sagebrush ('oots were still evident in the bottom of the soil pit. PEDON: Pedon is described under near-potential vegetation. Color is for dry soil unless otherwise stated.

All

0-8 cm (0-3 in)

A12

8-20 cm (3-8 in)

B1

20-43 cm (8-1'7 in)

IIB2t

43-66 cm (17-26 in)

(Under grass) Dark grayish brown (10YR 4/2) silty clay loam, very dark brown (10YR 2/2) moist; weak thin platy structure; soft; very friable; sticky, plastic; many medium and fine roots; many fine interstitial pores; slight effervescence in spots; neutral (pH 6.6); few fine angular basalt pebbles; clear smooth boundary. Dark grayish brown (lOYR 4/2) silty clay loam; very dark brown (10YR 2/2) moist; weak medium and fine subangular blocky structure; hard; friable; sticky, plastic; many medium and fine roots; many medium and fine tubular pores; slight effervescence; common small fragments of strongly cemented secondary carbonate; neutral (pH 7.1); common angular basalt pebbles; clear wavy boundary. Grayish brown (10YR 5/2) heavy silty clay loam, very dark grayish brown (10YR 3/2) moist; weak medium and coarse prismatic structure; extremely hard; firm; sticky, plastic; many fine roots between peds; few fine tubular pores; slight effervescence; common fragments of strongly ce­ mented secondary carbonates; mildly alkaline (pH 7.4); abrupt wavy boundary. Brown (10YR 5/3) silty clay, dark brown (lOYR 3/3) moist; strong medium prismatic structure; extremely hard; very firm; very sticky, very plastic; common fine roots between peds; few fine tubular pores; many pressure faces; thin continuous clay films; slight effervescence; mildly alka­ line (pH 7.4); clear wavy boundary.

79

1IB31ca

66-81 cm (26-32 in)

IIB32ca

81-127 cm

(32-50 in)

IICca

127-165 cm (50-65 in)

IIR

165+ cm (65+ in)

80

Very pale brown (10YR 7/3) silty clay, brown (lOYR 5/3) moist; weak fine prismatic structure;

very hard; friable; sticky, plastic; common fine roots; common fine tubular pores; violent

effervescence; secondary carbonates as coatings around peds and as hard concretions; mildly

alkaline (pH 7.5); common rodent krotovina; gradual wavy boundary.

Very pale brown (lOYR 8/3) silty clay, pale brown (lOYR 6/3) moist; moderate medium prismatic

structure; extremely hard; firm; sticky plastic; common fine roots; few fine tubular pores; violent

effervescence; secondary carbonates as coarse veins and concretions; mildly alkaline (pH 7.7);

many flakes and concretions of manganese; common angular basalt stones, cobbles, and peb­

bles; common pressure faces; thin patchy clay films; common rodent krotovina; gradual wavy

boundary.

Very pale brown (lOYR 8/3) clay loam, pale. brown (lOYR 6/3) moist; massive; hard; friable;

slightly sticky, slightly pla.'!!tic; few fine roots; many fine tubular pores; violent effervescence; in

places stones weakly cemented with secondary carbonates; moderately alkaline (pH 8.0); abrupt

irregular boundary.

Bedrock.

Exhibit 8C.-Soillaboratory data, Gemson silty clay loam, thick surface variant

Study No.: UT 2-59 Location: Box Elder County, Utah Soil Survey Laboratory: SCS and Utah State University, Logan, Utah Lab. No.: U62457 to U62463 General Methods: lA, IBlb, 2Al, 2b ,

(nun)

PARTICLE SIZE DISTRIBUTION LAIORATORY NUMBER

DEPTH

HORIZON

cm U62457 U62458 U62459 U62460 U62461 U62462 U62463

0-8 8-20 20-43 43-66 66-81 81-127 P7-165

All Al2 Bl lB2t lB31ca lB32ca ICca

VERY COARSE SAND 2·1

3Al

COARSE MEDIUM CLAY FINE VERY FINE SILT SAND SAND SAND SAND 1·0.5 0.5·0.25 0.25 ·0.10 0.10·0.05 0.05·0.002 2 0.02 ~19)

Pet

Pet

TOOURAl CLASS

Pet

30.5

32.5

35.8

43.8

56.6

57.1

36.6

t

pH

,§Clb

SATURATED PASTE

MOISTURE TENSIONS ELECTRICAL ~~;e EST. GYPSUM COHDUC· meq TIVITY SALT [CliO 3 "ol••'anl /lOOg 1/10 1/3 (BUREAU MILLIMHOS ATMOS. ATMOS. ATMOS. SOIL CUP) ~RCM

ORGANIC MAnE"

BCla

Bela

1:10

1:5

6Ala

t!2

6Bls

ORGANIC CARBON NITROGEN

CIN

25·C

Pet

6.6 7.1 7.4 7.4 7.5 7.7 8.0

U62457 U62458 U62459 U62460 U62461 U62462 U62463

~tro~ EXCHANGE

Pet

3.11 0.264 11.8 2 .. 30 0.226 10.2 1.27 0.142 8.9 0.66 0.53 0.38 0.39

r

EXTRACTABLE CATIONS 5Bla

6N2b C.

602b ]6P2. 114, N,

CAPACI\:

,

Pet

'IIUequlwlerri "'

6QEa II

Sum

Pet

0.71 2.67 1.00 0.58 0.57 1.60 L06

0.15 0.10 0.09 0.10 0.09 0.10 0.15

.

5D2

Pet

0.73 0.97 9.00 6.00 36.60 36.10 50.70

Pet

17.2 19.1 19.6 23.3 22.2 23.9 23.7

I

BD3

~odiull

~at.

on











SATURATION EXTRACT SOLUBLE

,

It

co.

HCO l

NH40A c +---.. iIIi.quiv",nlS per IItlr

lOOt eoI

Pet

32.0 33.6 35.4 40.0 39.5 42.5 43.2

CI

so,

MOISTURE AT

CalMa

~ATUMTlO~

Pet

U62457 U62458 U62459 U62460 U62461 U62462 U62463

32.7 33.4 31.8 38.8 31.4 34.4 40.0

0.33 0.30 0.44 0.46 0,56 2.83 9.05

2.92 4.12 1.58 1.13 0.74 0.60 0.37

1 1 1 1 2 8 23

57

56

57

• 73

69

75

65

81

gg

Exhib;t 9A.-Total annual production, 1958-1.967, Goodington silt loarn a Study No. ID 18-58 Carey Kipuka, Idaho Plant species

1958

1959 Pet

Precipitation: 41 cm (16 in) Eleva,tion: 1,543 m (5,064 ft) Slope: SE 1 percent

1960 Pet

1961 Pet

1962 Pet

1963 Pet

1964 Pet

1965 Pet

1966 Pet

1967 Pet

Pet

kg/ha b compo kg/ha compo kg/ha camp. kg/ha camp. kg/hu compo kg/ha camp. kg/ha compo kg/hu compo kg/ha comp. kg/lla camp.

Gras:!es

Idaho fescue 186 29 146 25 216 29 103 19 223 17 121 10 194 29 268 27 Sandberg bluegrass 76 12 65 11 15 111 65 12 361 28 291 26 129 19 162 16 Bottlebrush squirreltail 86 13 41 7 58 8 50 10 128 10 221 20 91 13 131 13 Bearded blue bunch wheatgrass 37 6 55 10 50 7 40 7 93 7 87 67 8 10, 112 11 Prairie junegrass 5 1 8 1 8 1 11 2 31 2 34 3 7 J. 1 15 Thurber needlegrass 2 T" 5 1 18 1 11 1 7 1 Other grassesd 2 T 5 1 4 T Forbs Narrowleaf pussy toes 34 5 19 3 48 7 47 9 58 5 74 7 21 3 39 4 Western hawksbeard 37 6 20 3 53 10 77 6 39 4 30 4 106 10 Longleaf phlox 20 3 24 5 25 3 29 5 53 4 62 6 18 3 11 1 Tapertip onion 1 T 6 1 6 1 8 1 36 3 T 18 3 3 Edible milkvetch 5 1 13 2 8 1 27 2 28 3 9 1 41 4 Lambstongue groundsel 46 7 2 T 25 3 17 3 16 1 2 T 24 2 Other forbs' 28 4 83 14 93 12 59 11 105 8 90 8 17 3 31 3 Annuals Cheatgrass brome 1 T 1 T 11 1 8 1 1 T 2 T Other annuals' 6 1 13 2 13 2 6 1 22 2 10 1 12 2 46 5 Woody plants Basin big sagebrush 31 5 37 6 30 4 21 4 26 2 11 1 11 2 Threetip sagebrush 40 6 25 4 15 2 9 2 2 T 2 T Douglas rabbitbrush 18 3 17 3 10 1 7 1 7 11 1 39 6 1 24 2 Rubber rabbitbrush 30 5 5 1 1 T 3 T 4 T 6 1 Total annual production 646 100 594 100 744 100 544 100 1,299 100 1,109 100 670 100 1,019 100 Total estimated litter" 1,505 1,288 1,081 637 814 874 1,238 570 • Repeat studies based on 20 random estimated plots; 10 plots estimated in 1958.

b Pounds pel' acre = kilograms per hectare X 0.891.

Trace-less than 1 percent.

J Other grasses include oniongrass and sedge.

• Other forbs include pale a~oseris, low pussy toes, arrow leaf balsamroot, Indian paintbrush, thistle, tapertip hawksbeard, Nuttall larkspur, mat eriogonum, fritillary. stemless actinea, prickly lettuce, nineleaf lomatium, velvet lupine, oblongleaf bluebell, nodding microseris, and Beckwith violet. f Other annuals include littIefiower collinsia, delicate collomia, and bushy birdbeak. • Total estimated litter for 1958, 1959, and 1960 included humic mulch.

100 41 30 17

38

310 93 101 67 10 76

30

9

10 6 1 8

1

T

34

14

57

6

13

5

54

5

20 22

2 2

15 12 6

4

1

41

4

2 1

T T

6 93

T

16 6

6 2

67 9 12

6 1 1

3 268 435

100

1,038 521

100

9

1

C

cushior. eriogonum, yellow

Exhibit 9B.-Soil profile description, Goodington silt loam

STUDY NO.:

ID 18-58

ELEVATION: 1,543 IT! (5,064 ft) AVERAGE ANNUAL PRECIPITATION: MEAN ANNUAL TEMPERATURE: 6° C (43° F)

41 cm (16 in)

LOCATION: Near the center of the Carey Kipuka, Craters of the Moon National Monument, 42 km (26 mi) via road east of Carey, Blaine County, Idaho. It is just east of the center of Sec. 19, TIS, R24E (BPM), about 43°20' N., 113° 32' W. The site is about 30 km (18.5 mi) northeast of Study Site ID 17-58. LAND FORM: Srtake River Plain, nearly level and undulating upland, 1 percent southeast slope. CLASSIFICATION: Goodington silt loam, a member of the fine, montmorillonitic, frigid family of TYPIC P ALEXEROLLS. 1 PARENT MATERIAL: Loess with some basaltic ash and cinders. REMARKS: This study site consists of several small, irregularly shaped tracts. They are intermingled with larger areas of Hoelzle silt loam, deep variant (ID 17-58) but are clearly distinct from the latter. The bare soil surface, 0-5 cm (0-2 in), cracks on drying, and the cracks form prominent polygonai patterns. Polygons contain few roots and many vesicular pores, and have weak thin platy structure. Bare surface soil is slightly lighter in color than surface soil under plants. The A&B horizon consists of a rr.;xture of A2 and B2 soil materials. This pedon is characterized by a slightly acid to neutral mollic epipedon; a thin A2 horizon; a mildly alkaline argillic horizon; and a calcic horizon. PEDON:

Pedon is described under potential vegetation. Color is for dry soil unless otherwise noted.

All

0-10 cm (0-4 in)

A12

10-18 cm (4-7 in)

A13

18-28 cm (7-11 in)

B&A

28-38 cm (11-15 in)

IIB2lt

38-66 cm (15-26 in)

I

(Under grass) Dark grayish brown (10YR 4/2) silt loam, very dark grayish brown (10YR 3/2) moist; weak medium and thin platy structure; soft; friable; nonsticky, slightly plastic; many roots; many fine interstitial pores; few angular basalt pebbles; slightly acid (pH 6.5); clear smooth boundary. Brown (10YR 5/3) silt loam, dark brown (10YR 3/3) moist; weak medium platy structure; slightly hard; friable; nonsticky, slightly plastic; many roots; many medium and fine tubular pores; slightly acid (pH 6.5); clear smooth boundary. Brown (10YR 5/3) silt loam, dark brown (10YR 3/3) moist; weak medium subangular blocky structure; hard; friable; slightly sticky, slightly plastic; many roots; many medium and fine tubular pores; neutral (pH 6.6); few weathered basalt pebbles producing distinct yellowish red (5YR 5/6) mottles; ped thinly coated with bleached sand and silt grains; gradual smooth boundary. Brown (10YR 5/3) loam, dark brown (10YR 3/3) moist; moderate medium subangular blocky structure (ped is thickly coated with clean sand and silt; A2 tongues into the B2 horizon, light brownish gray (10YR 6/2) and dark grayish brown (10YR M2) moist); extremely hard; firm; sticky, plastic; common roots; common medium and fine tubular pores; neutral (pH 6.6); few weathered basalt pebbles producing distinct yellowish red (5YR 5/6) mottles; abrupt wavy boundary. Brown (10YR 5/3) silty clay, dark brown (10YR 3/3) moist; strong coarse columnar structure; extremely hard; very firm; very sticky, very plastic; common roots between peds; few fine tubular pores; few concretions of manganese; thin clay films and organic stains on vertical cleavage planes of columns; common pressure faces; mildly alkaline (pH 7.7); few weathered basalt pebbles producing distinct yellowish red (5YR 5/6) mottles; clear wavy boundary.

The current classification of this pedon would be ARIDIC P ALEXEROLL.

83

IIB22t

66-86 cm (26-34 in)

IIB23ca

86-114 cm (34-45 in)

!IB3ca

114-142 cm (45-56 in)

mC1ca

142-170 cm (56-67 in)

mC2a

170-213 cm (67-84 in)

mC3

213-244 cm (84-96 in)

IVR

244 cm (96 in)

84

Pale brown (10YR 6/3) silty clay, brown (10YR 5/3) moist; strong medium and coarse prismatic

structure; extremely hard; firm; very sticky, very plastic; few roots between peds; few fine tubular

pores; slight to strong effervescence; secondary carbonates as fine veins; centers of peds weakly

to noneffervescent; patchy clay films; common pressure faces; few weathered basalt pebbles

producing distinct yellowish red (5YR 5/6) mottles; few concretions of manganese; moderately

alkaline (pH 8.1); gradual smooth boundary.

Pale brown (10XR 6/3) silty clay, dark brown (10YR 4/3) moist; moderate medium prismatic

structure; very hard; firm; very sticky, very plastic; few roots between peds; common fine tubular

pores; strong effervescence; secondary carbonates occurring as coarse veins and soft pockets;

moderately alkaline (pH 8.0); thin patchy clay films; common pressure faces; gradual smooth

boundary.

Pale brown (10YR 6/3) silty clay, brown (10YR 5/3) moist; moderate medium prismatic structure;

very hard; firm; sticky, very plastic; few roots between peds; few fine tubular pores; violent

effervescence; secondary carbonates as coarse veins and soft pockets; moderately alkaline

(pH 8.0); few pressure faces; clear irregular boundary.

White (10YR 8/2) silty clay loam, pale brown (10YR 6/3) moist; massive; hard; friable; nonsticky,

slightly plastic; few roots; many medium and fine tubular pores; violent effervescence; weakly

cemented in places; moderately alkaline (pH 7.9); many basalt stones; clear irregular boundary.

Very pale brown (10YR 7/3) gravelly loam, brown (10YR 5/3) moist; massive; loose; very friable;

non sticky, nonplastic; few roots; strong effervescence; 30 percent gravel; contains thin carbonate­

cemented lenses; moderately alkaline (pH 8.0); clear wavy boundary.

Light brown (7.5YR 6/4) stony gravelly loam, brown (7.5YR 5/4) moist; massive; hard; strong

effervescence; carbonates as veins; moderately alkaline (pH 8.0); 35 percent stones and gravel;

abrupt wavy boundary.

Basalt bedrock.

•

Exhibit 9C.-Soil laboratory data, Goodington silt loam Swdy 1tional Monument, 42 km (26 mi) east via the road from east of Carey, Blaine County, Idaho. It is in the east c::enter of Sec. 19, TiS, R24E (RPM), about 43°20' N., 113°32' W. LAND FORM: Snake River Plain, gently sloping and undulating upland, 1 percent south-facing slope. CLASSIFICATtoN: Hoelzle silt loam, deep variant, a member of the fine, montmorillonitic, frigid family of ARIDIC CALCIC ARGIXEROLLS. P ARENT MATERIAL: Loess, basal tic ash, and cinders. REMARKS: The bare surface soil, 0-5 cm (0-2 in), cracks upon drying. Cracks form a prominent polygonal pattern. Polygons contain few roots and many vesicular pores and have weak thin platy structure. Color of bare surface soil is slightly lighter than that of surface soil under vegetatxon. This ped~n is similar to the Hoelzle series except that it is deeper than 102 cm (40 in) to bedrock. This pedon is ch-aracterized by a slightly acid mollic epipedon; a mildly alkaline silty clay argillic horizon; and a moderately alkaline silty clay calcic horizon. PEDON: Pedon is described under potential vegetation. Color is for dry soil unless otherwise stated.

All

0-13 cm (0-5 in)

A12

13-38 cm (5-15 in)

Bl

38-58 cm (15-23 in)

IIB21t

58-86 cm (23-34 in)

IIB22t

86-112 cm (24-44 in)

(Under grass) Dark grayish brown (lOYR 4/2) silt loam, dark brown (10YR 3/3) moist; weak fine platy structure; soft; friable; nonsticky, non plastic; many roots; many fine interstitial pores; slightly acid (pH 6.3); clear wavy boundary. Dark brown (10YR 4/3) loam, dark brown (lOYR 3/3) moist; weak medium subangular blocky structure; slightly hard; friable; nonsticky, slightly plastic; many roots, many medium and fine tubular pores; slightly acid (pH 6.4); gradual smooth boundary. Brown (10YR 5/3) heavy loam, dark brown (lOYR 4/3) moist; moderate medium and fine angular and subangular blocky structure; extremely hard; very firm; sticky, plastic; common roots; com­ mon medium and fine tubular pores; slightly acid (pH 6.4); peds thinly coated with bleached sand and silt; common slightly weathered basalt pebbles produce faint yellowish red (5YR 5/3) mottles; abrupt wavy boundary. Brown (lOYR 5/3) Gilty clay, dark brown (lOYR 4/3) moist; moderate medium and coarse prismatic structure; extremely hard; very firm; very sticky, very plastic; common roots between peds; few fine tubular pores; thin continuous clay films; slight organic staining on prisms; common pressure faces; few flakes and concretions of manganese; common weathered basalt pebbles producing fine distinct yellowish red (5YR 5/6) mottles; mildly alkaline (pH 7.4); gradual smooth boundary. Pale brown (lOYR 6/3) silty clay, br.own (lOYR 5/3) moist; moderate medium prismatic structure; extremely hard; firm; very sticky, very plastic; common roots between peds; few fine tubular pores; thin continuous clay films; few pressure faces; calcium carbonate as fine veins on prism faces, inner part of prisms noneffervescent; few flakes and concretions of manganese; common weathered basalt pebbles producing fine distinct yellowish red (5YR 5/6) mottles; moderately alkaline (pH 8.0); gradual smooth bcundary.

87

IIB23ca

112-145 cm (44-57 in)

IIB3ca

145-173 cm (57-68 in)

Pale brown (10YR 6/3) silty clay, brown (10YR 5/3) moist; moderate medium prismatic structure; extremely hard; firm; very sticky, very plastic; few roots between peds; few fine tubular pores; strong effervescence; secondary carbonate occurring as veins; thin patchy clay films; few pressure faces; few flakes and concretions of manganese; common weathered basalt pebbles producing yellowish red (5YR 5/6) mottles; moderately alkaline (pH 8.0); gradual smooth boundary. Pate brown (10YR 6/3) silty clay, brown (10YR 5/3) moist; weak medium prismatic structure; very hard; friable; sticky, plastic; few roots between peds; common medium and fine tubular pores; strong effervescence; secondary carbonate 'Jccurring as coarse veins and soft pockets; many basalt pebbles; moderately alkaline (pH 8.2); gradual smooth boundary.

The following soil-horizon descriptions are approximate. Soil was excavated with a soil auger. IIC1ca IIIC2ca IIIC3ca

IVC4 VR

173-201 cm (68-79 in) 201-231 cm (79-91 in) 231-274 cm (91-108 in) 274-300 cm (108-118 in) 300 cm (118 in)

Very pale brown (10YR 7/3) silty clay loam, pale brown (10YR 6/3) moist; slightly hard; friable;

slightly sticky, plastic; violent effervescence.

Very pale brown (10YR 7/3) loam, pale brown (10YR 6/3) moist; violent effervescence containing

thin lenses of moderately cemented materials that were difficult to cut through with the soil

auger.

Very pale brown (10YR 7/3) silt loam, pale brown (10YR 6/3) moist; violent effervescence; many

basalt pebbles.

Pale brown (10YR 6/3) gravelly siJ~ loam, brown (10YR 5/3) moist; contains about 30 percent

basalt gravel (cinders); violent effervescence.

Basalt bedrock.

l

88

Exhibit lOC.-Soil laboratory data, Hoelzle silt loam, deep variant. Scudy No.:

-"'1.:;;.D_1:o..7_-.:;.S.:;.8_ _ _ _ _ _ _ _ _ _ _ _ _Soil No.: S5Bldaho-7-17

Soil Survey Laboratory: SCS, Lincoln, Nebraska General Methods: lA, IBlb, 2AI, 2B

Location: Slaine County, Idaho Date: September 1969

Lab. No.: 12715 to 12725 14647 to 14648

-~--'--'-'~-------

Size clus .nd pI,t,cle d.lmef., ImmJ ToUl OeDth

HOllzon

Soind

J

S.nd / S,It CI.y 12-1) 05, ,0 OS, • 0 002) 1/ 0002,

cm

V.ry

I

c..."

312 • .6-112 It2~1~5_. 1 5-1 J 17J-201 201-211 2)1-274 274-100

0.8 1.6 1.7

Wiler .t

S.lur,tlon

em

::1.1 'J.l 0."l

1.8 2.6

5D2

t!A O'Plh

2/

Pet

5j.6 48.6 ~,::!-

63.1

611.2

.JE.,J. ... 58.5 52.')

..l&...L 57.2 60.0

[lch,nae' .blt N.

6Hla eat.Ex~h.ea Ext. 5A3a SAla fddi t' Sl1m 1lHt,.oA ( Gati.:;rt

~

g- t--.-

5-Ba Wate 0.62

0.49 Q 4ti. 0.46 0.44 0·39 0.49

1.4 1.2 2.1

6

26.0 25.6

~1£l

7

10 .3 6.2 6.2 7.2 7.8

17.9

B.o 7·9 I.e. 9 8,1 7·9

_Q~8~

0.72 1.0

K

6.5

6:~ 6. 7.4 8.0

B.O 8.2

~·t 8.3 8.2

8Al BAla

6q).a

.

0.6 0·5

97.Q

o 69

0.87

N.

2·9 5.6 6."! 5.9 11.6 10.6 6.9 5.4

0.60

8

Mi

' 1.4

Pet

1.1 0·92 ..•. 0.85 ·0.84 0.74

c.

33.3 30.0

Ratios to Clay J3D

-_

Pet

Wlter tdrlct hom Sllur.ited pastt

26.B 21.B

30.B 41.5

NH;,:A:

pH

8elb BCla Sat. Paste {Ill

10.4 n.8 IB.2 17.6 16.4 16.7 14.3

37.2

2->"7

m40k CEe

_6

19

21

10.~

19·7 19.6

O.~

GYPlum

Pet

26.7 26.2

0·5 O.B

CEC f'ct 104 101 L .. _ 104_ 2 105

6

~.2

6.5 4.1 2.4

2.2 2.6 SCI Base Sat

Pet

6Pla

..

::>.2

Pet

4

3.~ 20.5 1.8 19·7 0.1 22.7 0.7 34.B 0.6 O.M 0.6 0·5

tr

4

1,~6

m,qilOO i

12.+ 12.3

tr

tr

4B2 15­ Bar

21.0

r

2-19119'76

f--.:~~ ~m--

Wlter content

5 _

Sum

K

28 --2. 24.4 22.1 22.3 22·9 27.8

18.9

Depth

cm

8.9 7.6 6,2

3·9 4.1 3·7

2.? 3.8

2l

() ./J':J

6::2a

20--2. 13.0 12.2 12.3

glcm 3 I g/cm3 IltJ-;;-m3 1.U 1.17 1.44 1.512 1.68 1.52 1.eC

6 .:; Ie 7 28

5BIa [llucl,aD1t Dues 602a 6P2a 6Q2a

57.7

Oven dry

Pct

".ct p-:-al 14

21.6

Bulk denSity

c.eo 1 0.73 66-112 6.0..Y 0.5 0.3 14.1 3.0 3.2 2.8 3.0 0.1 14.~ 3.2 1.0 0.86 112-163 7.3.J12.3 0 5 1~ 1 2'" ~ ~ 51 226 04 5.8 24.1 3.4 3.22 ~.+-____~7u. ~2~~1~2~~~~~O~.·7-+____ ~____~1~2-~:2~,lL:U~~-+.~2-~:8L4~1~8~:~~4~~1~:0~~1~:0~__~____~7~.1~+~59.~.1~1~0~.~2-F6~.9~

5A Oe,'h

em

u- tlJ

E~eh'nlle

5'lur,alton

able N.

Pet

,CI

,t

Base Sat. tlli4'JA

1

6F1a

Pet

3 11 112

.lQ.'i.-

atios to

':1~8D2

Gypsum ~lli40A

15-Ba \olater

CEe

CE·:

102

~

:±i:.o

•

Pe~

96

4C.;J

10-}'

2

(.:19 )

TOOURAL

CLASS

Pat 31 15

MOISTURE TENSIONS

GYPSUM

meq /lOOg

Pat

5D2 ~od1ulI ~at.%

Pat

SOIL

25°C

Pat

3A1

t~2

1/10 ATMOS.

1/3 ATMOS.

Pet

Pat

Pat

19.5 17.0 18.3 24.8 24.2 22.4

8.5 8.2 9.1 7.9 7.6 7.5

25.3 20.6 30.5 39.7 39.7 32.4

ATMOS.

SATURATION EXTRACT SOLUBLE It

CO,

BD3 MOISTURE

HCO.

llliequilli 1111,., IIIIr

CI

so.

AT

pajMg

5ATURATiOI

Pat U62436 U62437 U62438 U62439 U62440 U62441

14.1 15.5 1.2.6 10.6 11.2 12.0

0.39 0.32 0.37 1. 41 3.13 3.03

0.84 0.91 0.76 0.98 1.15 0.85

3 2 3 13 28 25

36 36 39 38 38 37

107

.....



00

Precipitation: 2a cm (9 in) Elevation: 1,440 m (4,726 ft) Slope: N 19 percent

Exhibit 16A.-Total annual production, 1958-1967, Rose-worth silt loam· Study No. ID 6-58 Little Crater Kipuka, Idaho Plant species

1958

1960

1959

Pet

Pet

Pet

1961

1963

1962

Pet

Pet

1964

Pet

1966

1965

Pet

Pet

1967

Pet

Pet

kg/ha b romp. kg/ha romp. kg/ha romp. kg/ha romp. kg/ha romp. kg/ha romp. kg/ha comp. kg/ha romp. kg/ha romp. kg/ha romp.

Grasses Bearded blue bunch wheatgrass 277 168 25 26 186 31 439 45 28 256 29 247 281 2a 42 365 249 32 364 2:1 Sandberg bluegrass 92 9 48 7 183 19 75 208 26 364 30 59 6 100 12 20 2 58 12 4 Thurber needlegrass 130 12 6 6 10 13 78 62 41 6 39 5 39 3 55 83 67 9 248 18 Other grasses· 17 2 2 T T ~ T 3 1 2 T 6 Forbs I·' Arrowleaf balsam root 118 94 74 12 14 95 10 66 10 45 7 7 67 8 226 29 209 84 15 Beardtongue 78 64 10 93 5 8 88 9 54 8 82 10" 9 9 43 17 2 110 113 8 Tapertip hawksbeard 8 31 4 92 83 34 4 9 1 6 1 2 9 18 2 6 1 44 3 25 Hoods phlox 44 4 27 5 3 15 3 81 46 7 43 28 2 21 26 2 S 22 3 3 Longleaf phlox 15 1 19 3 26 3 18 3 17 2 40 3 45 4 6 1 17 2 34 3 Nineleaf lomatium 1 12 1 4 25 3 22 1 T 13 9 3 12 38 3 1 2 1 T 1 Tapertip onion 8 1 13 1 19 T T 1 9 3 1 11 1 2 T 1 32 2 Other forbs' 18 3 8 2 19 67 7 56 5 2 35 9 39 67 6 1 13 T 3 3 Annuals Cheatgrass brome 1 3 T T 2 T 9 1 2 T 2 T 2 2 13 1 T T Other annuals' 1 T 1 T 2 T 1 T 7 1 T 3 T 1 T 4 T 2 Woody plants Wyoming big sagebrush 6 69 10 65 57 6 52 8 32 4 4 10 3 100 45 1 25 7 Threetip sagebrush 2 34 5 17 20 24 1 3 43 5 36 3 37 37 5 121 15 48 3 4 DolIglas rabbitbrush 19 1 2 T 10 36 3 2 9 32 3 3 25 12 2 25 2 5 Plains pricklypear 11 1 2 T T 1 Antelope bitterbrush 7 1 T 1 1 1 T T Total annual production 1,005 100 668 100 984 100 653 100 811 100 1,220 100 1,056 100 810 100 786 10e 1,373 100 Total estimated litter'" 1,693 2,072 825 1,159 1,674 809 756 940 896 1,256 • Repeat studies based on 20 random estimated plots; 10 plots estimated in 1958.

b Pounds per a'~re = kilograms per hectare X 0.891.

c Other grass'.lS include prairie junegrass, Nevada bluegrass, bottlebru!lh squirrel tail, and rteedleandthread.

d Trace-lesa than 1 percent.

• Other forbs included pale agoseris, low pussytoes, timber milkvetch, mariposa lily, Indian paintbrush, western hawksbeard, Nuttall larkspur, eriogonum, yellow fritillary, MacDoUgal lomatium, oblongleaf bluebell, and foothill deathcamas. . r Other ~nnuals include littleftower collinsia ancl delicate collomia. g Total estimat~d litter for 1958, 1959, and 1960 included humic mulch.

.I.

~-"" ~~,

-

'

'

.

Exhibit 16B.-Soil profile description, Roseworth silt loam

STUDY NO.: ID 6-58 AVERAGE ANNUAL PRECIPITATION: 23 cm ELEVATION: 1,440 m (4,726 ft) MEAN ANNUAL TEMPERATURE: 8° C (46° F)

~S

in)

LOCATION: Power County, Idaho, north side of the Little Crater Kipuka, 34 km (21 mi) northwest of American Falls, SW Ih, Sec. 24, T6S, R28E (BPM), 42°52' N., 113°08' W. LAND FORM: Sloping and rolling upland, Snake River Plain, 19 percent north-facing slope. CLASSIFICATION: Fine-loamy, mixed, frigid family of ORTHIDIC DURIXEROLLS. PARENT MATERIAL: Loe.ss and some basalt. REMARKS: The soil is defined as having a fine-loamy control section, more than 18 percent clay and more than 15 percent coarser than very fine sand, including coarse fragments up to 7.5 cm (3 in). Laboratory data show this pedon to have 17.9 percent clay and less than 15 percent coarser than very fine sand. However, pebbles discarded at the time of sampling are considered sufficient to qualify this pedon as having a fine-loamy .control section. The Rosew,Jrthname is tentative, as a series name has not been finally approved for this soil. This soil is characterized by a neutral to mildly alkaline mollic epipedon, a mildly alkaline B horizon, a moderately alkaline calcic horizon, and a duripan at a depth of 94 cm (37 in). 'r

About 58 percent of the ground surface is bare, 8 percent is covered by stones, and 34 percent is covered by vegetation, litter, or both. Bare surface soils are slightly lighter than surface soils under vegetation and crack upon drying. Cracks 2-5 cm (1-2 in) deep form a prominent polygonal pattern. Polygons have weak thin platy structure and contain many vesicular pores and a few fine roots. Cicada nymph burrowing is extensive in this soil. Soil structure in the B2, B3ca, and C1ca horizons has been influenced by their activity. Roots of bearded bluebunch wheatgrass are observed to a depth of 94 cm (37 in). PEDON: J>edon is described under near-potential vegetation. Color is for dry soil unless otherwise stated. A1

0-8 cm (0-3 in)

B1

8-20 cm (3-8 in)

B2

20-48 cm (8-19 in )

(Under grass) Dark grayish brown (10YR 4/2) light silt loam, very dark grayish brown (10YR 3/2) moist; weak thin platy structure; soft; friable; nonsticky, slightly plastic; many medium and .fine roots; many fine interstitial pores; neutral (pH 7.0); common fine basalt pebbles; clear smooth boundary. Brown (10YR 5/3) silt loam, dark brown (10YR 3/3) moist; weak medium and fine subangular blocky structure; soft; friable; nonsticky, slightly plastic; many medium and fine roots; many medium and fine tubular pores; mildly alkaline (pH 7.4); common basalt pebbles; gradual smooth boundary. Brown (10YR 5/3) silt loam, dark brown (10YR 3/3) moist; weak medium and coarse prismatic structure; hard; friable; nonsticky, slightly plastic; common fine roots; common fine and very fine tubular pores; mildly alkaline (pH 7.5); common basalt pebbles; abrupt wavy boundary,

109

.

B3ca

48-64 cm (19-25 in)

Clca

64-94 cm (25-37 in)

C2sicam

94-117 cm (3'7-46 in)

IIR

117 cm (46 in)

110

Very pale brown (lOYR 8/3) silt loam, brown (10YR 5/3) moist; strong medium and fine angular

and subangular b!acky structure; very hard; friable; nonsticky, slightly plastic; common fine roots

mostly between peds; few fine tubular pores; strong effervescence; moderately alkaline (pH 8.1);

common basalt pebbles; gradual wavy boundary.

Very pale brown (10YR 8/3) silt loam, br.own (IOYR 5/3) moist; strong medium and fine angular,

subangular, and cylindrical blocky structure; very hard; friable; nonsticky, slightly plastic; com­

mon fine roots m03tly between peds; fewfili2 tubular pores; strong effervescence; moderately

alkaline (pH 8.3); abrupt wavy boundary.

Pinkish white (7.5YR 8/2) duripan,light brown (7.5YR 6/4) moist; duripan contains thin lenses

and pockets of pink (7.5YR 5/4) fine sandy loam containing many fine roots and fragments of

duripan; common basalt stones; strongly alkaline (pH 8.8); abrupt irregular boundary.

Basalt bedrock.

Exhibit 16C.-Soil laboratory data. Roseworth silt loam St;udy t;o.:

...

..:I"'C•....;:.6-_S::;8=-_ _ _ _ _ _ _ _ _ _ _ _ _ _ _Soil No.:

Soil Survey Laboratory: SCS. Lincoln. Nebraska Genera 1 Het h0 d s; A. Bib. 2AI. 2B

Lab. No.:

S581daho-7-6

Location:

10783 to 10788 ]4631 to 14633

Date:

SUt cius and Plrtlcle

Tot., a,gth

Hafltan

J

~'" t.""

5.." I S,1l CI.y ,2~O Or, to OS· ,..- 000,,1 1/ 0002,

cn \i-t"

1\1

"='2.l.

':-2v

?l

C!e.~

2v-4--

p~

~.:>

4:)

Precipitation: 23 cm (9 in) Elevation: 1,334 m (4,378 it) Slope: S 11 percent

Exhibit 17A.-Total annual production, 1958-1967, Trevino extr.mzeiy stony silt loam· Study No. ID 12-58 Little Crater Kipuka, Idaho

1959

1958

Plant species

kg/ha b Grasses Bearded bluebunch wheatgrass Sandberg bluegrass Thurber needlegrass Bottlebrush squirreltail Forbs Arrowleaf balsam root Tapertip hawks beard Longleaf phlox MacDougal lomatium Cushion eriogonum Low fleabane Other forbs d Annuals Cheatgrass brome Other annuals'

136 113 97

1965

1964

1963

1962

1961

1960

23

134 47

10

84

28

46 48 6

10 10 1

6 2 2

1 T T

1

T

23

8 14

2

TO

55 45 29 13 2 5

9 8 5 2

17 35 25 43 30 6 46

2 4 3 5 4 1 5

1

31 2

T

26 17 9 2

126 67 53 2

24 13 10

40 43

6 7 4

25

25

1 4

20 11 3 35

20 6

3 1

9 1

T

19 24 6

T

159 206 55 3

168 106 59 10

3

15 32 18 18

2

11

T

5

8 39

3 6 3 3 2 2 8

1

4 1

T

T

T

4

....

,

~

,.

29 19 14 3

140 20 31 1

52 8 12

106 18 18 5 1 3 2

16 3 3 1

S5

13 4

36

5

22

196

20 12 1

128

T

176 161 95 6

20

7 2 4 1 2 3 4

69 99 19 32 9 12 10

9 12 2 4 1 2 1

41 1

7

39 1

5

T

T

165 65 50 1

29

40 9 22

8 10

15

11

9

Woody plants 9 21 74 196 23 119 128 25 131 22 112 18 Wyoming big sagebrush 81 17 Antelope biUerbrush 2 T Rock gilia 2 T 802 100 856 100 566 100 522 100 598 100 642 100 Total annual production 540 100 898 676 610 743 971 Total estimated litter' 997 1,009 • Repeat studies based on 20 random estimated plots; 10 plots estimated in 1958.

b Pounds per acre = kilograms per hectare X 0.891.

. .... '"

«S 0.>

>


0.>

"0

'0

.... ~

...., ....

r::

0

~

c

.J:>

A verage annual production

....,'"

r::

«S ~

Co 0

«S

bIl

~

0.>

'"

'"

::s r:: r::

-
.

's;.



rn

...,

>187 >173

f,mo,fr c-si,m,fr

Xerollic Natrargids Xerollic Calciorthids

60 60

10 10

0.44 0.57

0.062 0.088

6.6 1.8

7.7 7.3

28 13

21 17

22 0

1.40 1.39

145 188 188

17

0

1.32 1.88

20

1

91 180 94 137 94

21

2

Il::

C11/,J

I·sk,m,me l-sk,m,me c-si,m(cal), me f-si,m,me

I,m,me,shal Aridic Petrocalcic

Palexerolls

Eo
~

co-I,m,fr

l,m,me

--;

0

..,...

...'"

'0 rn

o·Cii

Fairfield Ola g cos I, deep variant

Trevino ex st sil

0

0

2 2 2

Little Crater Kipuka Waycup ex st sil Neeley I, fine-loamy subsoil variant Neeley sil, mod deep/bedrock variart Neeley silo deep/bedrock variant Neeley sil, deep/bedrock variant Kucera sil, deep/bedrock variant Roseworth sil. Trevino ex st sil

~

c a:

C.

-'

c

60 60 60

Kettle Butte Kipuka Brunt sil, heavy subsoil variant Pancheri sil

0

'bD C

0)

'"

'0

-0

Pachic Argixerolls Pachic Argixerolls Aridie Natrixerolls

Kearns sil

.....0

-0 C ::l

k

'" '" 00

::IbD

Q)

f.l,m,fr' f·l,m,fr f,mo,!r

7

Parent matetials b

...

'" ...'"c

.c

"' .... S.c

Emigrant Pass Simon sil, thick surface variant' Simon sil, thick surface variant Pie Creek, sil taxadjunct

Hansel Valley Abela g I Abela g I Pomat 1

..,

C.



'b .....

0)

11/,eq/

,

'"

:;;

0

'" ~

c

0

·c

'"

-0

...

.!l

c

1.26 1.22

Q) ~

0

u

c

meta meta meta meta meta

...bD

'"

Q)

'" '"'"

--; '"

::I

C

c



!

Pet

I­

CJ

a!

...!:O

v

0

Ul

:::> ...,

X

.;;

~

:3u c::: '"

Z.

Ul

Ci.i

p:;

cm d

Pel

1.08 1.28

>183 186

24-NW

1.24 1.35 1.35

>183 >183 >183

a!

~£1

.: .:.-

0 u

.. -~~

Ul

U

Uc.>u

pH

PeL

I­

ro

'0

oceQ

~~;-

'" ;E

""-, E.s::

u·­

o·w

1:0

..::;:::S

:>1:0

>-:"8 Woo

>~

7l1eq/ 'ln1lt/(',,)IL

lOOg

Pet g/{,,)1L 3d

:5

'"'0

a!

Q.

Parent materials

b

... :> '"

...

-g

:>

:::>

""0 '"J:!

I­

cem Q:l

Pet

Pel

Pet

cm u

mixed res sed, a ign mixed res sed, a ign

17 18

0 1

37 39

734 901

eol meta & ign eol meta & ign col meta & ign

17 18

67 58 70

446 492

8

0 0 0

ro

'"0 ....,

Pachit' Haploxerolls Pachic Argixerolls

60 60

1 1

Morgan Pasture Kipuka Newdale sil Newdale sil Brunt sil

e-si,m,fr e-si,m,fr I-si,m,fr

Calciorthidic Haploxero[fs Calciorthidic Haploxerolls Xerollic Natrargids

59 59 59

10 1 5

North Thermopolis Butte Unnamed sil

f-I,m,me

Ustollic Camborthids

66

1

1.36

>145

4-NW

eol mixed sed

28

0

42

Owl Creek Trump st I Woosley 1, calcic variant Lanark 1 Ard g I, deep variant

I,m r-I,m f-si,m co-l,m,me

Lithic Cryoborolls Argic Cryoborolls Pachic Argic Cryoborolls Calcic Cryoborolls

61 61

25 91 170 >99

2-NW 4-NE 4-NW 4-NW

mixed mixed mixed mixed

27 30 33 23

44

1.34 1.39

61

2 2 2 1

Owyhee Hoelzle ex st sil Gemson ex st sil. cool variant

f,mo,fr f,mo,fr

Aridie Calcic Argixerolls Calcic Argixerolls

66 66

1 1

Paddock Valley Rel>ervoir DeMasters ex st I, deep variant

l-sk,m,me

Pachic Haploxerolls

60

2

Paul Portneuf sil, noncal variant Porlneuf sil, noncal variant

co-si,m,me co-si,m,me

Xerollic Camborthids Xerollic Camborthids

59 59

1 1

Provo Canyon Unnamed g I Unnamed g sil

[-sk,m,me f-I,m,me

Petrocalcic .Palexerolls Typic Calcixerolls

60 60

1 1

1.15 1.38

0.195 0.230

1.1 0.8

7.4 7.6

3 8

28

Rattlesnake Pass Gemson v g sil Gemson sicl, thick surface \'ariant G()mson v st sil K()arns sil, calcareous surface var Middle ex st sil

f,mo,me f,mo,me f,mo,me f-si,m,me l-sk,m,me

Calcic Argixerolls Pachic Argixerolls Calcic Argixerolls Typic Calcixerolls Calcic Haploxerolls

58 59 59 59 58

4 10 1 3 1

0.56 0.94 0.71 0.76 1.25

0.088 0.184 0.135 0.132 0.183

0.6 1.3 LO 0.9 0.9

6.6 7.2 6.9 7.3 7.4

0 5 6 5 0

26 33 28 26 34

Red Canyon Game Refuge Woosley stl

f-I,m

Argic Cryoborolls

Gl

Riverdale Unnamed I

l'-I,m,me

Typic Calcixerolls

Table Mountain Unnamed g I

f-lls-sk.m

Thatcher Fielding sil, heavy subsoil variant

61

0.35

0.025

0.8 7.0

6.7

0

7.0

2

18 15

0 0 14

1.23

I-S 183

24-NE

mixed res sed

19

6

41

1,022

34

814

94

202

1,144

2

2,119

Wind River Unnamed v st 51

l-sk,m

Argic CryobQrolls

65

1

1.82

>79