ARKANSAS
SOIL FERTILITY STUDIES 2000
R.J. Norman and S.L. Chapman,
Editors
ARKANSAS AGRICULTURAL EXPERIMENT STATION Division of Agriculture March 2001
University of Arkansas Research Series 480
Layout by Marci Milus; Technical Editing and Cover Design by Robin Bodishbaugh Arkansas Agricultural Experiment Station, University of Arkansas Division of Agriculture, Fayetteville. Milo J. Shult, Vice President for Agriculture and Director; Gregory J. Weidemann, Associate Director, Arkansas Agricultural Experiment Station. PS1.0301PM65. The Arkansas Agricultural Experiment Station follows a nondiscriminatory policy in programs and employment. ISSN:0099-5010 CODEN:AKAMA6
ARKANSAS SOIL FERTILITY STUDIES
spine copy
2000
Norman and Chapman
AAES
ARKANSAS SOIL FERTILITY STUDIES – 2000 – R.J. Norman1 and S.L. Chapman2, Editors 1
Crop, Soil, and Environmental Sciences Department University of Arkansas, Fayetteville, AR 2 Cooperative Extension Service Little Rock, AR
Arkansas Agricultural Experiment Station Fayetteville, Arkansas 72701 1
INTRODUCTION The 2000 Soil Fertility Studies includes research reports on numerous Arkansas commodities and on several research areas including topics associated with precision agriculture. For more information on any topic, please contact the author(s). Also included is a summary of soil test data from samples submitted for the 2000 growing season. This set of data includes data for counties, soil association physiographic areas, and selected cropping systems. Funding for the associated soil fertility research programs came from commodity check-off funds, state, federal, the fertilizer industry institutes, and lime vendors. The fertilizer tonnage fee provided funds not only for soil testing, but also for research and publication of this research series. Extended thanks are given to state and county extension staffs, staffs at extension and research centers and branch stations, farmers, and cooperators, and fertilizer industry personnel who assisted with the planning and execution of the programs. Readers are reminded that the 1996 Arkansas Soil Fertility Studies (Research Series 455) contains the index to articles in the previous Arkansas Soil Fertility Research Series. This publication is available online at http://www.uark.edu/depts/agripub/Publications/researchseries/. Additional printed copies of this publication can be obtained free of charge from Communications Services, 110 Agriculture Building, University of Arkansas, Fayetteville, AR 72701. R.J. Norman and S.L. Chapman, Editors Department of Crop, Soil, and Environmental Sciences University of Arkansas and Cooperative Extension Service Little Rock, Arkansas
ACKNOWLEDGMENT Arkansas Fertilizer Tonnage Fees funded the publication of this research series.
CONTRIBUTORS P. Anderson, Student Assistant, Crop, Soil, and Environmental Science Department, Fayetteville W.H. Baker, Research Assistant Agronomist, Soil Test Lab, Marianna R. Benson, Research Associate, Northeast Research and Extension Center, Keiser D.L. Boothe, Research Specialist, Rice Research and Extension Center, Stuttgart S.D. Carroll, Research Specialist, Soil Test Lab, Marianna S.L. Chapman, Extension Soils Specialist, Cooperative Extension Service, Little Rock S.D. Clark, Research Specialist, Pine Tree Branch Experiment Station, Colt D.L. Coker, Research Specialist, Crop, Soil, and Environmental Sciences Department, Fayetteville K. Combs, County Extension Agent - Agriculture, Cooperative Extension Service, Dardanelle M.D. Correll, Research Specialist, Crop, Soil, and Environmental Science Department, Fayetteville M.B. Daniels, Extension Agronomist, Cooperative Extension Service, Little Rock R.E. DeLong, Research Specialist, Crop, Soil, and Environmental Sciences Department, Fayetteville L.R. Fry, Research Specialist, Crop, Soil, and Environmental Sciences Department, Fayetteville J.T. Gilmour, Professor, Crop, Soil, and Environmental Sciences Department, Fayetteville R.E. Glover, Research Specialist, Northeast Research and Extension Center, Keiser S.K. Gomez, Graduate Assistant, Crop, Soil, and Environmental Sciences Department, Fayetteville J. Gunsaulis, County Extension Agent - Agriculture, Cooperative Extension Service, Fayetteville J.A. Hedge, Research Specialist, Arkansas State University, Jonesboro W.F. Johnson, Jr., Extension Agronomist, Cooperative Extension Service, Little Rock R.C. Kirst, Jr., Research Specialist, Southeast Research and Extension Center, Monticello J.S. McConnell, Associate Professor, Southeast Research and Extension Center, Monticello J.H. Muir, Assistant Professor, Arkansas State University, Jonesboro S. Ntamatungiro, Associate Extension Specialist, Rice Research and Extension Center, Stuttgart
D.M. Oosterhuis, Distinguished Professor, Crop, Soil, and Environmental Sciences Department, Fayetteville W.E. Sabbe, Professor, Crop, Soil, and Environmental Sciences Department, Fayetteville N.A. Slaton, Extension Agronomist - Rice, Rice Research and Extension Center, Stuttgart K. Teague, County Extension Agent - Agriculture, Cooperative Extension Service, Fayetteville D. Zhao, Research Associate, Crop, Soil, and Environmental Sciences Department, Fayetteville
CONTENTS SOIL TEST AND FERTILIZER SALES DATA: SUMMARY FOR THE GROWING SEASON – 2000 R.E. DeLong, S.D. Carroll, and W.H. Baker ........................................................... 1 INFLUENCE OF SITE-SPECIFIC OR FIELD-AVERAGE APPLICATIONS OF PHOSPHORUS AND POTASSIUM FERTILIZERS ON GRAIN YIELD OF SORGHUM W.E. Sabbe and R.E. DeLong ................................................................................. 18 PLANT UPTAKE OF ZINC BY SORGHUM IN RESPONSE TO ZINC FERTILIZERS W.F. Johnson, Jr., and R.E. DeLong ....................................................................... 21 INFLUENCE OF PHOSPHORUS FERTILIZER ON PHOSPHORUS UPTAKES AND GRAIN YIELDS OF WHEAT FOLLOWING RICE R.E. DeLong, W.F. Johnson, Jr., and M.D. Correll ............................................... 24 AGRONOMICS OF FIELD-AVERAGE OR SITE-SPECIFIC APPLICATIONS OF PHOSPHORUS AND POTASSIUM FERTILIZERS ON WHEAT R.E. DeLong, W.F. Johnson, Jr., M.D. Correll, and W.E. Sabbe ......................... 27 TEMPORAL VARIABILITY OF SOIL PHOSPHORUS IN PASTURES AMENDED WITH ANIMAL MANURE M.B. Daniels, S.L. Chapman, J. Gunsaulis, K. Teague, and K. Combs ............. 34 A NEW APPROACH TO LIME RECOMMENDATIONS IN ARKANSAS J. Gilmour and P. Anderson ..................................................................................... 39
CROP YIELDS VERSUS SOIL TEST VALUES USING GLOBAL POSITIONING SYSTEM / GEOGRAPHIC INFORMATION SYSTEM TECHNOLOGY J.T. Gilmour, L.R. Fry, and N.A. Slaton ................................................................ 42 CORN RESPONSE TO PHOSPHORUS AND POTASSIUM FERTILIZATION AT VARIOUS SOIL TEST LEVELS J. H. Muir and J. A. Hedge ........................................................................................ 49 CORN RESPONSE TO NITROGEN AND PHOSPHORUS AS STARTER FERTILIZER J.H. Muir and J.A. Hedge .......................................................................................... 52 PHOSPHORUS FERTILIZER RATE AND APPLICATION TIME EFFECT ON SOYBEAN YIELD N.A. Slaton, R.E. DeLong, S. Ntamatungiro, S.D. Clark, and D.L. Boothe ............. 54 LONG-TERM IRRIGATION METHODS AND NITROGEN FERTILIZATION RATES IN COTTON PRODUCTION: THE LAST FIVE YEARS J.S. McConnell, W.H. Baker, and R.C. Kirst, Jr. ....................................................... 59 NITROGEN FERTILIZATION OF ULTRA-NARROW-ROW COTTON J.S. McConnell, R.C. Kirst, Jr., R.E. Glover, and R. Benson .................................... 63 VARIETAL RESPONSES OF COTTON TO NITROGEN FERTILIZATION J.S. McConnell, W.H. Baker, and R.C. Kirst, Jr. ....................................................... 67 EFFECT OF FOLIAR-APPLIED CoRoNTM SLOW-RELEASE NITROGEN FERTILIZER ON COTTON YIELDS D.M. Oosterhuis and S.K. Gomez ............................................................................. 70 CHANGES IN TISSUE BORON CONCENTRATIONS IN THE COTTON PLANT DURING DEVELOPMENT OF BORON DEFICIENCY D. Zhao and D.M. Oosterhuis ................................................................................... 73 YIELD RESPONSE TO SOIL AND FOLIAR POTASSIUM FERTILIZATION OF WATER-DEFICIT-STRESSED COTTON D.L. Coker and D.M. Oosterhuis .............................................................................. 78
SUMMARY Rapid technological changes in crop management and production require that the research efforts also be presented in an expeditious manner. The contributions of soil fertility and fertilizers are major production factors in all Arkansas crops. The studies contained within will allow producers to compare their practices with the university’s research efforts. Additionally, soil test data and fertilizer sales are presented to allow comparisons among years, crops, and other areas within Arkansas.
Arkansas Soil Fertility Studies 2000
SOIL TEST AND FERTILIZER SALES DATA: SUMMARY FOR THE GROWING SEASON – 2000 – R.E. DeLong, S.D. Carroll, and W.H. Baker BACKGROUND INFORMATION Soil test data from samples submitted by Arkansas farmers and growers to the University of Arkansas Soil Test Lab during the period 1 September 1999 through 30 August 2000 were categorized according to geographic area, county, soil association number (SAN), and selected cropping system. This sampling period roughly corresponds to the 2000 crop growing season; therefore, those samples should represent the soil fertility of that cropping season. The geographic area and SAN were from the General Soil Map, State of Arkansas (December 1982). The statistical interpretation of the soil test data included categorical ranges for pH, phosphorus (P), potassium (K), nitrate-nitrogen (NO3-N), and soluble salts (i.e., electrical conductivity, EC). Soluble salts and NO3-N can be indexes for possible soil contents that may lead to adverse soil growing conditions or leaching potentials. Soil pH plus soil test (Mehlich III) values indicate the soil fertility level. RESULTS Crop Acreage and Soil Sampling Intensity In the interval from 1 September 1999 through 30 August 2000, soil samples representing a total of 1,379,614 acres were submitted through the University of Arkansas Soil Testing Program. These 54,106 samples resulted in fertilizer and lime recommendations in all counties with each sample representing an average of 26 acres. The samples that were included in the report had complete data in all of the county, soil association number, last crop, geographic area, total acres, pH, P, K, NO3-N, EC, month, day, and year categories. Samples that did not have values in all of those categories were not included in this report. Samples by geographic area were dominated by Bottom Land and Terrace and Loessial Plain, which also had the greatest acres/sample (Table 1). The county average ranged from 2 to 64 acres/sample (Table 2). The lowest county sample number was 9 and the highest county sample number was 2,527. The average by SAN indicates the predominance of row crops and pasture (Table 3). The higher values originate either from the Delta SAN where cotton, rice, wheat, and soybean prevail or from rangeland SAN where cool- and warm-season hay and pasture production occurs. The crops involved indicate that, in addition to row crops and pasture, turf, and garden enterprises contributed largely to the samples submitted to the program (Table 4).
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AAES Research Series 480
Soil Test Data Values in Tables 5, 6, 7, and 8 pertain to the fertility status of the soils as categorized by geographic area, county, SAN, or the suggested 2000 crop category, respectively. Soil test values relate to the fertility of a soil, but not necessarily to the productivity of the soil. Therefore, it may not be realistic to compare soil test values among SAN without knowledge of location and cropping system. Likewise, soil test values among counties cannot be realistically compared without knowledge of the SAN and the profile of the cropping systems. Soil test data for cropping systems can be compared; however, the specific cropping systems dictated past fertilizer practices and, hence, current soil test values. For example, cotton has a history of intensive fertilization, whereas dryland soybean has not been subjected to intensive fertilization. Similarly, rice can be produced on soils low in P and K, and those soil test values for the commodity reflect that fact. The acidity of Arkansas soils is demonstrated by the 22% sampled acreage that has a pH less than 5.5. From a beneficial standpoint, the accumulation of soluble salts and leachable nitrogen (NO3-N) is low, with 84 and 85% for each in the lowest category, respectively. Table 8 contains the median (Md) for each of the cropping system categories. The median, being the soil test value that has equal number of entities above and below, should be a better interpreter of a soil’s fertility status than the percentage profile of the samples. Among row crops the lowest P and K median values appear for rice and irrigated soybeans. As expected, the highest P and K median values are for cotton. Fertilizer consumption by county (Table 9) and by form (Table 10) for the state illustrate the wide use of fertilizer predominantly in row-crop counties and in nitrogen and bulk forms. PRACTICAL APPLICATIONS The data can be viewed with the perspective of establishing a statewide, countywide, or commodity educational program on soil fertility and fertilization practices. The data are rather general, and more specific categories (e.g., soybean in Arkansas county for SAN 44) should be generated for those purposes. Comparisons and contrasts among counties, SAN or cropping systems would give the specific data needed for these programs.
ACKNOWLEDGMENT Financial support from the Arkansas Fertilizer Tonnage Fee is appreciated.
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Arkansas Soil Fertility Studies 2000
Table 1. Sample number and acreage by geographic area in Soil Test Program from September 1999 through August 2000. Geographic area Ozark Highland - Cherty Limestone and Dolomite Ozark Highland - Sandstone and Limestone Boston Mountain Arkansas Valley and Ridge Ouachita Mountain Bottom Land and Terrace Coastal Plain Loessial Plain Loessial Hill Blackland Prairie
Acres sampled
No. of samples
118,638
7,298
16
11,310 24,210 62,065 32,959 606,124 51,739 455,004 14,059 3,506
600 1,786 5,835 4,174 17,821 3,541 11,712 1,132 207
19 14 11 8 34 15 39 12 17
Acres/sample
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Table 2. Sample number and acreage by county in Soil Test Program from September 1999 through August 2000. County Arkansas (DE) Arkansas (ST) Ashley Baxter Benton Boone Bradley Calhoun Carroll Chicot Clark Clay (CO) Clay (PI) Cleburne Cleveland Columbia Conway Craighead Crawford Crittenden Cross Dallas Desha (DU) Desha (MC) Drew Faulkner Franklin (CH) Franklin (OZ) Fulton Garland Grant Greene Hempstead Hot Spring Howard Independence Izard Jackson Jefferson Johnson Lafayette Lawrence
4
Acres No. of Acres/ sampled samples sample 88,441 92,457 24,945 2,804 25,033 8,541 1,495 232 10,760 6,792 3,728 23,201 21,270 4,156 544 1,868 7,411 59,068 6,656 27,392 89,087 393 282 21,923 2,704 4,517 1,181 2,344 4,068 4,379 401 32,586 4,844 1,790 6,005 8,106 5,622 27,106 44,447 7,191 9,693 18,424
1,913 2,320 656 354 1,623 549 254 39 636 296 237 806 759 339 50 192 405 2,234 440 847 1,663 92 9 1,996 192 517 46 149 206 1,498 117 1,369 244 158 327 432 303 673 1,346 479 236 672
46 40 38 8 15 16 6 6 17 23 16 29 28 12 11 10 18 26 15 32 54 4 31 11 14 9 26 16 20 3 3 24 20 11 18 19 19 40 33 15 41 27
County
Acres No. of Acres/ sampled samples sample
Lee Lincoln Little River Logan (BO) Logan (PA) Lonoke Madison Marion Miller Mississippi (BL) Mississippi (OS) Monroe Montgomery Nevada Newton Ouachita Perry Phillips Pike Poinsett Polk Pope Prairie (DA) Prairie (DB) Pulaski Randolph Saline Scott Searcy Sebastian (FS) Sebastian (GR) Sevier Sharp St. Francis Stone Union Van Buren Washington White Woodruff Yell (DN) Yell (DR)
93,709 16,956 6,912 1,448 8,034 96,471 8,591 2,363 9,641 32,726 6,458 57,542 1,761 982 1,519 702 3,033 30,671 4,349 54,345 4,075 26,243 20,390 16,849 5,609 15,554 652 914 11,755 935 1,655 6,420 5,487 15,347 2,792 1,125 3,830 39,353 23,249 16,086 7,777 1,417
1,474 580 193 233 376 2,527 625 173 359 1,323 225 934 116 87 113 192 192 1,148 211 1,670 315 1,109 512 330 1,648 713 181 70 577 469 121 288 391 473 213 315 357 2,278 2,336 499 395 92
64 29 36 6 21 38 14 14 27 25 29 62 15 11 13 4 16 27 21 33 13 24 40 51 3 22 4 13 20 2 14 22 14 33 13 4 11 17 10 32 20 15
Arkansas Soil Fertility Studies 2000
Table 3. Sample number and acreage by soil association number in Soil Test Program from September 1999 through August 2000. Soil Association Number - Soil Association
Acres sampled
No. of samples
Acres/ sample
1-Clarksville-Nixa-Noark 2-Gepp-Doniphan-Gassville-Agnos 3-Arkana-Moko 4-Captina-Nixa-Tonti 5-Captina-Doniphan-Gepp 6-Eden-Newnata-Moko 7-Estate-Portia-Moko 8-Brockwell-Boden-Portia 9-Linker-Mountainburg-Sidon 10-Enders-Nella-Mountainburg-Steprock 11-Falkner-Wrightsville 12-Leadvale-Taft 13-Enders-Mountainburg-Nella-Steprock 14-Spadra-Guthrie-Pickwick 15-Linker-Mountainburg 16-Carnasaw-Pirum-Clebit 17-Kenn-Ceda-Avilla 18-Carnasaw-Sherwood-Bismarck 19-Carnasaw-Bismarck 20-Leadvale-Taft 21-Spadra-Pickwick 22-Foley-Jackport-Crowley 23-Kobel 24-Sharkey-Alligator-Tunica 25-Dundee-Bosket-Dubbs 26-Amagon-Dundee 27-Sharkey-Steele 28-Commerce-Sharkey-Crevasse-Robinsonville 29-Perry-Portland 30-Crevasse-Bruno-Oklared 31-Roxana-Dardanelle-Bruno-Roellen 32-Rilla-Hebert 33-Billyhaw-Perry 34-Severn-Oklared 35-Adaton 36-Wrightsville-Louin-Acadia 37-Muskogee-Wrightsville-McKamie 38-Amy-Smithton-Pheba 39-Darco-Briley-Smithdale 40-Pheba-Amy-Savannah 41-Smithdale-Sacul-Savannah-Saffell 42-Sacul-Smithdale-Sawyer 43-Guyton-Ouachita-Sardis 44-Calloway-Henry-Grenada-Calhoun 45-Crowley-Stuttgart 46-Loring 47-Loring-Memphis 48-Brandon 49-Oktibbeha-Sumter
19,896 11,909 12,757 68,517 2,307 3,252 3,231 8,079 10,065 14,145 1,334 20,295 5,059 2,367 33,010 10,803 4,648 9,222 2,083 2,748 3,455 101,185 55,933 89,089 98,100 44,209 8,859 24,605 37,490 835 7,761 110,684 16,910 7,210 265 2,702 287 5,444 1,089 7,865 11,895 17,233 8,213 247,534 207,470 1,922 11,783 354 3,506
1,216 1,015 830 4,002 67 168 221 379 598 1,188 21 2,156 326 126 3,206 1,880 230 1,736 97 110 121 3,185 892 1,802 3,121 1,663 233 809 2,195 30 326 2,823 410 164 16 110 42 243 190 435 1,003 1,282 388 6,850 4,862 118 998 16 207
16 12 15 17 34 19 15 21 17 12 64 9 16 19 10 6 20 5 22 25 29 32 63 49 31 27 38 30 17 28 24 39 41 44 17 25 7 22 6 18 12 13 21 36 43 16 12 22 17
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Table 4. Sample number and acreage by crop in Soil Test Program from September 1999 through August 2000. Crop Soybean - dryland Soybean - irrigated Cotton Rice Wheat Double-crop wheat-soybean - dryland Double-crop wheat-soybean - irrigated Warm-season grass - establish Warm-season grass - maintain Cool-season grass - establish Cool-season grass - maintain Grain sorghum Corn All garden Turf and ground cover Fruit and nut Vegetable Other
6
Acres sampled
No. of samples
Acres/sample
73,564 517,262 247,590 90,489 19,733 11,601 20,761 6,456 112,940 1,817 68,185 8,554 15,229 15,819 7,402 2,008 653 159,551
2,182 12,418 6,759 2,212 645 287 611 299 4,925 96 3,172 216 347 3,849 6,171 430 34 9,453
34 42 37 41 31 40 34 22 23 19 22 40 44 4 1 5 19 17
z
300 176- 221350
K (lb/acre) 26100
NO3-N (lb/acre)
100500
ECz (µmhos/cm)
56
61 56 55 51 60 51 43 50 45
17
18 27 27 37 13 31 11 23 21 21 17 18 12 27 18 46 27 34
27
11 7 14 7 11 11 26 22 19 17 11 12 11 18 11 32 22 21
6 10
28 24 23 26 46 22 32 31 26
22
31 33 33 36 24 33 9 19 24
34
13 25 18 20 1 23 1 6 10
28
33 25 32 36 16 36 33 25 23
24
15 11 14 17 13 14 23 18 8
11
27 30 28 27 36 25 31 36 23
26
25 34 26 20 35 25 13 21 46
39
81 78 78 70 93 85 93 84 83
73
18 20 19 25 6 13 6 14 16
24
1 2 3 5 1 2 1 2 1
3
87 81 81 76 92 85 87 80 69
76
13 19 18 23 8 15 13 19 31
23
0 0 1 1 0 0 0 1 0
1
---------------------------------------------------------- Percentage of sampled acreage ------------------------------------------------
5.56.5
P (lb/acre)
EC = electrical conductivity; which is a measure of soluble salts.
Ozark Highland - Cherty Limestone and Dolomite Ozark Highland - Sandstone and Limestone Boston Mountain Arkansas Valley and Ridge Ouachita Mountain Bottom Land and Terrace Coastal Plain Loessial Plain Loessial Hill Blackland Prairie
Geographic area
pH
Table 5. Soil test data by geographic area from samples submitted from September 1999 through August 2000.
Arkansas Soil Fertility Studies 2000
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Arkansas (DE) Arkansas (ST) Ashley Baxter Benton Boone Bradley Calhoun Carroll Chicot Clark Clay (CO) Clay (PI) Cleburne Cleveland Columbia Conway Craighead Crawford Crittenden Cross Dallas Desha (DU) Desha (MC) Drew Faulkner Franklin (CH)
County 300
P (lb/acre) 176- 221350
K (lb/acre) 26100
NO3-N (lb/acre) 100500
ECz (µmhos/cm)
4 9 15 7 17 15 22 39 9 16 34 13 14 30 24 35 33 11 23 12 6 47 56 8 19 37 37 32 54 60 24 59 54 37 51 54 45 44 71 68 54 68 49 55 56 58 59 29 47 44 56 63 50 50 64 37 25 69 24 31 41 10 37 39 22 16 18 16 8 16 12 33 19 29 65 6 0 36 18 13 13 30 36 12 5 2 5 6 5 3 20 19 28 13 9 8 5 16 14 17 1 26 19 33 3 17 15 33 40 28 10 8 4 11 8 21 7 16 19 37 15 10 4 10 11 17 13 12 36 23 44 13 18 17 17 25 28 42 16 17 32 19 18 18 32 19 31 37 24 18 18 25 42 19 60 32 24 0 61 35 27 28 4 7 34 32 35 35 40 44 38 28 25 3 34 24 32 35 21 26 32 26 5 26 22 23 24 29 13 1 1 2 39 42 17 27 12 34 4 18 1 1 33 38 32 27 1 19 1 1 8 1 0 6 12 9 34 27 16 10 21 28 28 62 17 14 40 45 18 24 32 35 32 17 36 2 38 59 0 10 24 25 50 29 21 15 9 9 12 10 10 8 7 14 24 14 11 6 19 14 12 11 3 24 19 22 10 16 15 15 30 33 48 28 26 27 27 18 27 34 25 25 40 30 34 27 19 37 26 27 26 19 33 31 30 28 17 7 19 21 53 44 33 35 10 48 45 21 6 28 35 28 19 35 34 27 68 12 3 45 49 30 32 18 96 91 92 67 74 83 80 90 61 91 87 94 92 81 90 87 79 92 79 97 97 91 100 94 88 73 87 4 9 8 22 22 15 14 10 35 9 10 6 8 18 6 10 16 7 18 3 3 9 0 6 12 22 13 0 0 0 1 4 2 6 0 4 0 3 0 0 1 4 3 5 1 3 0 0 0 0 0 0 5 0 88 82 88 59 74 81 80 97 68 81 77 95 95 81 92 85 82 89 86 96 87 91 89 89 87 77 87
0 0 0 3 2 0 1 0 1 0 1 0 0 0 0 0 0 1 1 0 0 0 0 0 0 1 0 continued
12 18 12 38 24 19 19 3 31 19 22 5 5 19 8 15 18 10 13 4 13 9 11 11 13 22 13
---------------------------------------------------------- Percentage of sampled acreage ------------------------------------------------
5.56.5
pH
Table 6. Soil test data by county from samples submitted from September 1999 through August 2000.
AAES Research Series 480
Franklin (OZ) Fulton Garland Grant Greene Hempstead Hot Spring Howard Independence Izard Jackson Jefferson Johnson Lafayette Lawrence Lee Lincoln Little River Logan (BO) Logan (PA) Lonoke Madison Marion Miller Mississippi (BL) Mississippi (OS) Monroe
County
Table 6. Continued.
300
P (lb/acre) 176- 221350
K (lb/acre) 26100
NO3-N (lb/acre)
100500
ECz (µmhos/cm)
24 14 40 33 15 21 39 36 16 18 13 16 20 23 15 18 23 27 33 22 15 22 5 20 24 15 7 71 49 51 54 64 58 54 57 57 59 63 53 60 46 65 63 49 43 52 65 59 67 50 43 64 50 53 5 37 9 13 21 21 7 7 27 23 24 31 20 31 20 19 28 30 15 13 26 11 45 37 12 35 40 5 14 5 9 19 10 7 6 10 15 23 5 12 6 33 3 8 23 31 13 16 4 4 5 0 3 24 18 19 10 9 31 15 14 5 15 20 26 13 15 16 28 11 12 19 13 15 25 7 13 19 3 6 25 25 37 30 18 35 25 38 11 32 20 34 53 17 37 30 55 37 26 20 31 42 20 30 27 46 39 38 28 23 41 48 14 27 29 26 23 34 14 25 32 23 7 30 33 26 26 30 15 33 32 30 50 51 11 24 7 14 16 1 23 12 52 20 11 3 4 24 18 2 1 10 6 10 11 2 36 21 19 1 1 2 29 33 38 27 30 30 48 27 32 37 26 18 28 21 31 11 20 44 44 42 19 20 13 26 4 6 29 16 15 19 15 19 12 16 12 13 17 20 11 13 9 23 13 12 12 11 14 17 12 10 11 6 6 19 30 26 30 34 37 23 25 23 29 25 37 37 29 26 31 39 26 18 23 20 38 25 34 27 44 27 34 25 26 13 24 14 35 11 38 26 21 17 34 30 44 15 37 42 26 22 24 26 43 43 36 46 61 18 83 81 49 82 93 80 91 79 76 77 92 93 84 81 93 96 84 94 75 86 90 77 74 80 90 94 93 15 16 40 17 6 19 8 17 22 22 8 6 15 17 7 3 14 6 19 13 9 22 25 19 10 6 7 2 3 11 1 1 1 1 4 2 1 0 1 1 2 0 1 2 0 6 1 1 1 1 1 0 0 0
88 85 65 83 95 78 90 82 77 84 91 90 89 81 87 96 81 87 83 86 85 82 76 82 94 97 91
0 0 1 1 0 0 0 0 0 0 0 0 0 1 0 0 1 0 2 0 0 1 1 0 0 0 0 continued
12 15 34 16 5 22 10 18 23 16 9 10 11 18 13 4 18 13 15 14 15 17 23 18 6 3 9
---------------------------------------------------------- Percentage of sampled acreage ------------------------------------------------
5.56.5
pH
Arkansas Soil Fertility Studies 2000
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10
Montgomery Nevada Newton Ouachita Perry Phillips Pike Poinsett Polk Pope Prairie (DA) Prairie (DB) Pulaski Randolph Saline Scott Searcy Sebastian (FS) Sebastian (GR) Sevier Sharp St. Francis Stone Union Van Buren Washington White
County
Table 6. Continued.
300
P (lb/acre) 176- 221350
K (lb/acre) 26100
NO3-N (lb/acre) 100500
ECz (µmhos/cm)
41 33 25 39 35 13 37 5 36 35 13 11 33 9 32 36 38 23 39 26 15 14 23 22 31 16 26 49 59 57 45 54 57 50 34 52 51 54 55 48 60 53 56 54 50 45 64 56 44 53 58 57 61 54 10 8 18 16 11 30 13 61 12 14 33 34 19 31 15 8 8 27 16 10 29 42 24 20 12 23 20 6 24 6 20 16 5 6 22 8 11 23 32 9 21 13 9 8 11 25 5 18 11 10 9 6 4 17 22 12 12 7 11 16 8 30 10 11 40 49 10 40 17 19 13 15 15 7 18 27 11 7 11 9 16 26 24 31 16 17 60 16 31 21 22 29 15 24 29 28 14 28 26 17 14 25 44 16 23 32 22 27 23 29 41 43 27 18 27 16 34 31 7 4 36 8 23 49 39 25 33 29 27 17 34 44 33 36 32 23 11 10 14 29 1 43 1 27 25 1 0 21 2 19 9 12 23 10 45 12 1 29 17 18 29 8 42 40 23 52 34 13 48 35 42 36 35 39 26 38 47 33 31 24 38 21 27 17 33 39 28 26 31 15 18 12 18 15 15 12 18 12 14 27 23 19 20 14 6 12 19 10 9 14 16 12 16 12 12 17 24 25 38 23 23 42 23 26 24 23 29 33 32 26 21 40 21 29 31 21 28 38 22 28 35 27 31 19 17 27 7 28 30 17 21 22 27 9 5 23 16 18 21 36 28 21 49 31 29 33 17 25 35 21 80 95 72 85 84 95 90 94 79 78 95 93 78 94 87 69 80 58 66 84 83 88 78 91 79 70 84 15 5 21 11 16 5 10 6 16 19 5 7 20 5 11 31 18 35 30 15 14 11 22 7 18 28 15 5 0 7 4 0 0 0 0 5 3 0 0 2 1 2 0 2 7 4 1 3 1 0 2 3 2 1 87 81 77 85 92 93 94 87 82 86 88 92 75 95 88 70 79 70 70 84 84 86 76 85 84 78 83
0 0 3 1 0 0 0 0 1 1 1 0 1 0 2 0 0 2 0 0 0 0 0 1 0 0 1 continued
13 19 20 14 8 7 6 13 17 13 11 8 24 5 10 30 21 28 30 16 16 14 24 14 16 22 16
---------------------------------------------------------- Percentage of sampled acreage ------------------------------------------------
5.56.5
pH
AAES Research Series 480
z
300
P (lb/acre) 176- 221350
K (lb/acre) 26100
NO3-N (lb/acre)
100500
ECz (µmhos/cm)
13 43 27 23 67 51 47 54 20 6 26 23 19 23 21 14 30 11 17 17 37 21 21 28 11 28 20 27 3 17 21 14 33 50 32 30 18 11 10 14 37 21 26 29 12 18 32 27 95 88 88 85 5 11 10 14 0 1 2 1
94 93 87 85
6 6 12 15
0 1 1 0
---------------------------------------------------------- Percentage of sampled acreage ------------------------------------------------
5.56.5
pH
EC = electrical conductivity; which is a measure of soluble salts.
Woodruff Yell (DN) Yell (DR) Average
County
Table 6. Continued.
Arkansas Soil Fertility Studies 2000
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12
1-Clarksville-NixaNoark 2-Gepp-DoniphanGassville-Agnos 3-Arkana-Moko 4-Captina-Nixa-Tonti 5-Captina-DoniphanGepp 6-Eden-Newnata-Moko 7-Estate-Portia-Moko 8-Brockwell-BodenPortia 9-LinkerMountainburg-Sidon 10-Enders-NellaMountainburgSteprock 11-Falkner-Wrightsville 12-Leadvale-Taft 13-Enders-MountainburgNella-Steprock 14-Spadra-Guthrie-Pickwick 15-Linker-Mountainburg 16-Carnasaw-Pirum-Clebit 17-Kenn-Ceda-Avilla 18-Carnasaw-SherwoodBismarck
Soil Association Number– Soil Association 300
P (lb/acre) 176- 221350
K (lb/acre) 26100
NO3-N (lb/acre) 100500
ECz (µmhos/cm)
57 45 56 60 39 51 58 63 56
56 52 51 65 52 57 49 61 53
19 11 13 17 37 42 13 20 20
30 29 31 26 44 24 33 30 40 17
9 4 19 18 9
14 19 18
24
17
24 7 29
44 31 23
24
5
12 20 11 9 11 9
11 16 10 12 11
7 11 57 29 18 15
5 11
15 20
11 19 11 13 4 11
16 17 7 12 3 7
4 10
27
25 17 23 24 22
24 14 23
25
29
31 33 28
24 20 20
26
39
26 34 37 34 30
34 0 28
31
28
31 35 37
24 35 36
35
20
26 13 19 21 26
24 0 16
28
8
8 8 20
19 26 34
25
40
29 41 30 31 48
27 57 34
21
38
13 28 24
26 22 24
25
18
14 16 15 18 10
11 10 13
12
16
27 13 13
12 11 10
12
28
25 26 30 28 20
29 29 27
30
25
30 27 29
26 26 26
24
14
32 17 25 23 22
33 4 26
37
21
30 32 34
36 41 40
39
54
77 88 83 80 82
80 86 72
74
81
72 77 81
79 67 71
77
36
22 11 16 18 14
18 14 24
23
19
27 20 18
16 30 26
21
10
1 1 1 2 4
2 0 4
3
0
1 3 1
5 3 3
2
69
82 91 84 78 86
83 91 78
76
88
72 80 85
77 73 76
77
1
1 0 0 1 0
0 0 1
1
0
0 0 1
2 1 1
0
continued
30
17 9 16 21 14
17 9 21
23
12
28 20 14
21 26 23
23
---------------------------------------------------------- Percentage of sampled acreage ------------------------------------------------
5.56.5
pH
Table 7. Soil test data by soil association number from samples submitted from September 1999 through August 2000.
AAES Research Series 480
19-Carnasaw-Bismarck 20-Leadvale-Taft 21-Spadra-Pickwick 22-Foley-Jackport-Crowley 23-Kobel 24-Sharkey-Alligator-Tunica 25-Dundee-Bosket-Dubbs 26-Amagon-Dundee 27-Sharkey-Steele 28-Commerce-SharkeyCrevasse-Robinsonville 29-Perry-Portland 30-Crevasse-Bruno-Oklared 31-Roxana-DardanelleBruno-Roellen 32-Rilla-Hebert 33-Billyhaw-Perry 34-Severn-Oklared 35-Adaton 36-Wrightsville-Louin-Acadia 37-Muskogee-WrightsvilleMcKamie 38-Amy-Smithton-Pheba 39-Darco-Briley-Smithdale 40-Pheba-Amy-Savannah 41-Smithdale-SaculSavannah-Saffell
Soil Association Number– Soil Association
Table 7. Continued.
300
P (lb/acre) 176- 221350
K (lb/acre) 26100
NO3-N (lb/acre)
100500
ECz (µmhos/cm)
42 59 50 64 59 64 62 64 63 55 54 90 52 57 49 42 69 58 74 46 50 49 46
32 24 39 11 8 13 10 23 13 9 10 7 19 12 9 20 19 38 19 32 33 34 34 20
7 22 17 17
29 31 42 38 12 4
36 36 3
26 17 11 25 33 23 28 13 24 7 11 13 34 33 13 15 6 15
12 12 22 18 6 15
11
9
14 21 15 16 21 7 9 15
14 5 12 12 19 66
4 10 10 18 7 40
4 21 8 27 21 5 7 3 1
19
24 24 14 37
33 54 40 46 25 13
59 56 43
34 29 27 32 38 49 47 41 50
31
21 36 43 28
30 28 20 21 25 5
27 16 7
34 26 26 6 7 32 30 47 32
30
20 9 15 11
11 1 6 3 25 1
0 0 3
21 13 26 1 1 1 1 3 2
34
38 44 49 38
30 11 16 23 38 48
5 12 30
23 51 36 31 27 5 15 9 1
13
19 14 17 12
14 12 13 18 13 26
4 10 7
21 11 16 23 22 9 11 6 2
25
24 22 24 27
27 42 36 27 25 22
35 26 27
29 15 27 34 39 34 38 41 21
28
19 20 10 23
29 35 35 32 24 4
56 52 36
27 23 21 12 12 52 36 44 76
81
91 88 91 90
86 95 92 88 100 93
93 91 93
73 95 81 95 95 97 95 89 86
15
7 12 9 9
11 5 8 12 0 7
7 9 7
25 5 17 5 4 3 5 10 13
4
2 0 0 1
3 0 0 0 0 0
0 0 0
2 0 2 0 1 0 0 1 1
83
91 89 91 88
87 91 88 85 100 95
94 87 90
87 96 85 93 95 94 93 93 89
0
0 0 0 0
0 0 0 0 0 0
0 0 0
1 0 1 0 0 0 0 0 1
continued
17
9 11 9 12
13 9 12 15 0 5
6 13 10
12 4 14 7 5 6 7 7 10
---------------------------------------------------------- Percentage of sampled acreage ------------------------------------------------
5.56.5
pH
Arkansas Soil Fertility Studies 2000
13
14
z
300
P (lb/acre) 176- 221350
K (lb/acre) 26100
NO3-N (lb/acre) 100500
ECz (µmhos/cm)
55 60 42 46 51 50 75 45 56
27 27 14 7 32 23 0 1 22 44 47 17 27 25 54 22
18 13 21 32 14 23 19 19 14 31 34 31 21 38 21 17
11 11 7 9 36 28 34 31 19 26 30
23 15 11 6 17 19 19 24 26
34 32 1 0 4 6 5 10 13
21 37 36 29 37 23 50 23 29
36 23 22 25 22 18 13 8 14
15 13 30 33 27 38 19 23 28
26 22 12 13 14 21 18 46 29
23 42 94 93 75 85 81 83 85
84 87 6 7 24 13 19 16 14
14 12 0 0 1 2 0 1 1
2 1 89 84 75 81 69 69 85
85 81
11 16 23 18 31 31 15
15 19
0 0 2 1 0 0 0
0 0
---------------------------------------------------------- Percentage of sampled acreage ------------------------------------------------
5.56.5
pH
EC = electrical conductivity; which is a measure of soluble salts.
42-Sacul-Smithdale-Sawyer 43-Guyton-Ouachita-Sardis 44-Calloway-HenryGrenada-Calhoun 45-Crowley-Stuttgart 46-Loring 47-Loring-Memphis 48-Brandon 49-Oktibbeha-Sumter Average
Soil Association Number– Soil Association
Table 7. Continued.
AAES Research Series 480
y
z
300 Md
P (lb/acre) 176- 221350 Md
K (lb/acre) 26100 Md
NO3-N (lb/acre)
100500 Md
ECz (µmhos/cm)
61 47 65 52 51 55 46 53 61 57 66 56 61 39 51 52 56 54 55
17 6 14 10 34 23 9 35 29 32 22 23 11 12 29 31 24 26 22 12 21 28 49 20 17 20 20 23
11
10
12
45
22
22 47 21 38 15
5.9 6.1 6.2 6.5 5.9 5.8 6.1 5.9
5.7
5.8
5.7
6.5
6.1
6.0 6.5 6.1 6.3 5.7
23 47 49 15 28 26 35 27 36
17
22
24
56
57
48 37 51 30 47
11 22 19 5 11 15 9 18 18
21
11
17
27
22
24 35 3 31 24
8 7 7 3 6 13 3 18 13
35
11
20
7
6
14 24 0 35 9
34 23 25 34 44 29 44 23 24
16
29
25
10
15
14 4 46 4 18
62
55
60
54 39 97 33 57
24 1 0 43 11 17 9 14 8
11 129 63 70 254 115 87 103 67
37
27 127
14
0
0
0 0 0 0 2
11 14 21 10 17 8 12 15 15
12
12
13
20
17
17 23 7 20 19
29 22 11 15 29 37 15 35 24
38
35
38
20
11
17 32 3 27 25
26 39 46 25 33 26 50 26 33
26
25
26
34
35
39 30 44 31 31 268 212 341 229 234
34 25 22 50 21 29 23 24 28
261 255 261 353 233 245 248 219
24 228
28 234
23 217
26 241
37 296
27 15 46 22 25
77 92 84 67 71 81 65 84 84
85
82
81
95
90
94 96 95 95 84
22 8 14 26 25 15 29 14 14
13
17
15
4
10
6 4 5 5 16
1 0 2 7 4 4 6 2 2
2
1
4
1
0
0 0 0 0 0
13 8 10 15 13 10 14 8
8
10
8
8
9
9 8 8 6 8
83 95 85 67 75 79 74 81 85
84
88
88
94
97
95 92 95 75 85
17 5 15 31 25 19 26 18 15
16
12
11
6
3
5 8 5 25 15
0 0 0 2 0 2 0 1 0
0
0
1
0
0
0 0 0 0 0
54 40 50 74 65 53 52 53
49
47
45
46
38
39 49 42 65 53
------------------------------------------------------------------------- Percentage of sampled acreage ----------------------------------------------------------------
5.56.5 Mdy
EC = electrical conductivity; which is a measure of soluble salts. MD = median; number is actual value, not the percentage.
Soybean - dryland Soybean - irrigated Cotton Rice Wheat Double-crop wheat soybean - dryland Double-crop wheat soybean - irrigated Warm-season grass establish Warm-season grass maintain Cool-season grassestablish Cool-season grassmaintain Grain sorghum Corn All garden Turf and ground cover Fruit and nut Vegetable Other Average
Crop
pH
Table 8. Soil test data by crop from samples submitted from September 1999 through August 2000.
Arkansas Soil Fertility Studies 2000
15
AAES Research Series 480
Table 9. Fertilizer sold in Arkansas counties from 1 July 1999 through 30 June 2000. County
Total
Arkansas Ashley Baxter Benton Boone Bradley Calhoun Carroll Chicot Clark Clay Cleburne Cleveland Columbia Conway Craighead Crawford Crittenden Cross Dallas Desha Drew Faulkner Franklin Fulton Garland Grant Greene Hempstead Hot Spring Howard Independence Izard Jackson Jefferson Johnson Lafayette Lawrence
86,409 25,867 3,937 7,344 8,038 4,440 448 3,934 22,076 1,456 51,260 3,292 103 606 8,335 59,346 10,191 20,564 52,677 1 43,962 5,074 7,022 3,806 1,751 209 350 28,452 6,227 1,903 1,724 16,125 3,827 35,651 34,655 2,045 3,091 31,635
County
ton
16
Total ton
Lee Lincoln Little River Logan Lonoke Madison Marion Miller Mississippi Monroe Montgomery Nevada Newton Ouachita Perry Phillips Pike Poinsett Polk Pope Prairie Pulaski Randolph St. Francis Saline Scott Searcy Sebastian Sevier Sharp Stone Union Van Buren Washington White Woodruff Yell
24,309 13,418 2,298 3,337 45,462 7,803 884 11,606 53,292 33,359 537 3,253 1,023 219 1,744 57,592 2,866 69,967 1,796 3,701 40,914 18,692 20,573 41,357 2,295 1,157 2,711 2,211 6,443 1,910 3,134 912 8,148 5,395 40,188 31,171 1,822
Arkansas Soil Fertility Studies 2000
Table 10. Fertilizer sold in Arkansas from 1 July 1999 through 30 June 2000. Fertilizer
Bulk
Bag
Fluid
Total
------------------------------------------ ton ----------------------------------------Mixed Nitrogen Phosphate Potash Other Total
381,372 506,605 16,915 37,275 27,417 969,583
43,089 3,394 223 297 1,941 48,944
20,455 125,560 0 181 603 146,800
444,916 635,559 17,138 37,753 29,961 1,165,327
17
AAES Research Series 480
INFLUENCE OF SITE-SPECIFIC OR FIELD-AVERAGE APPLICATIONS OF PHOSPHORUS AND POTASSIUM FERTILIZERS ON GRAIN YIELD OF SORGHUM W.E. Sabbe and R.E. DeLong RESEARCH PROBLEM The advent of site-specific agriculture, with its inclusion of monitoring yields on a small area, allows for the application of fertilizer via variable rate technology. Prior to the use of site-specific techniques, the goal of soil sampling was to obtain a sample that contained the mean values of a field. Traditionally, fertilizer was applied to an entire field based on the average of one bulked soil sample. Site-specific agriculture allows for numerous types of fertilizer and application rates within a field based on the soil analyses for each specific area of a field. The crop response must also be documented as to nutrient uptakes to facilitate the timing and rates of fertilizer applications. Our objectives were to compare nutrient uptakes and sorghum grain yields in response to phosphorus (P) and potassium (K) fertilizers in areas of a field treated with control, field-average, or site-specific fertilizer placement methods. BACKGROUND INFORMATION Rice yields and quality can be reduced due to site-specific field conditions such as low soil test levels, drainage, quality of irrigation water, and soil pH. A site was chosen at the Pine Tree Branch Experiment Station whose previous year’s rice crop exhibited a poor stand, reduced tillering, stunting, and reduced yield. Soil fertility of the site was determined with sorghum selected as an alternate crop to a normal wheatsoybean-rice rotation. RESEARCH DESCRIPTION The irrigated study was conducted in 1998, 1999, and 2000 at the Pine Tree Branch Experiment Station, Colt, on a Calloway (Glossaquic Fragiudalfs, fine-silty, mixed, thermic) soil. Twenty-nine soil samples of 6-inch depth were taken in the center of 20- by 40-ft quadrants in an 1.1 acre field. Soil samples were dried, ground, extracted with Mehlich III, and analyzed for P and K with an inductively coupled argon plasma (ICP) spectrophotometer. The field average for soil test P was 26 lb/acre and K was 241 lb/acre. The corresponding recommended fertilizer rates were 60 lb P2O5/acre and 60 lb K2O/acre. The area surrounding each soil sample point was divided into four equal plots of 40-ft long by 10-ft wide with four 30-inch rows. Two plots were left untreated as control areas. The third plot was fertilized by the fieldaverage method, which was based on all the soil test points in the field. The fourth plot
18
Arkansas Soil Fertility Studies 2000
was fertilized by the site-specific method, which was based on the recommended fertilizer rate for the specific soil sample point enclosed by the four plots. The fertilization rates for the site-specific areas were 60-0, 60-60, and 60-90 lb P2O5-K2O/acre, respectively. The P and K fertilizer treatments for the field-average and site-specific methods were applied by broadcast and incorporated before planting. Cultivars ‘Terral TV1050’, ‘Asgrow A603’, and ‘Terral TV1050’ were planted in 1998, 1999, and 2000, respectively. Leaf and whole plant samples were obtained at the 6-lf and full bloom stages, respectively. Plant samples were dried, ground, digested with nitric acid, and analyzed for P and K with an ICP. Grain yields were determined at crop maturity. RESULTS Nutrient uptakes shown by leaf and whole plant analysis for P and K in 1998, 1999, and 2000 were not significant for fertilizer treatment or methods of fertilizer placement (data not shown). Grain yields for methods of fertilizer placement were significant in 1998 for the 60-0 and 60-60 site-specific fertilizer placement methods with treatments ranging from 66.4 to 87.6 and 74.0 to 82.8 bu/acre, respectively (Table 1). Grain yields for methods of fertilizer placement were not significant in 1998 for the sitespecific fertilizer rate of 60-90 lb P2O5-K2O/acre with the range of 74.1 to 83.1 bu/acre. Grain yields for methods of fertilizer placement were not significant in 1999 for the sitespecific fertilizer rate of 60-0 and 60-60 lb P2O5-K2O/acre with the range of 95.9 to 113.3 and 102.4 to 113.3 bu/acre, respectively. Grain yields were substantially lower in 2000 compared to the previous two years of the study due to a poor stand. Grain yields for methods of fertilizer placement were significant in 2000 for the site-specific fertilizer rate of 60-60 lb P2O5-K2O/acre with treatments ranging from11.6 to 37.3 bu/acre. Grain yields for methods of fertilizer placement were not significant in 2000 for the sitespecific fertilizer rate of 60-0 and 60-90 lb P2O5-K2O/acre with the range of 11.8 to 24.0 and 14.0 to 21.5 bu/acre, respectively. PRACTICAL APPLICATIONS This experiment is a first step in understanding the influence of various recommended fertilizer rates on soils with specific P and K soil test levels compared to traditional fertilization based on the field average. This greater understanding will assist in the application of P and K fertilizers to specific areas of a field that may require different amounts of fertilizer. ACKNOWLEDGMENT Financial support from the Arkansas Fertilizer Tonnage Fee is appreciated.
19
AAES Research Series 480
Table 1. Irrigated sorghum grain yields as affected by phosphorus (P) and potassium (K) fertilizers as applied by field-average or site-specific fertilizer placement methods, Pine Tree Branch Experiment Station, Colt, Arkansas, 1998-2000. Grain yield 1999
Fertilizer placement method
1998
lb P2O5–K2O/acre
------------------------- bu/acre ------------------------
2000
Site-specific (0-60)z Field-average Nontreated LSD(0.05)
66.4 78.4 87.6 18.6
104.5 95.9 113.3 NSy
11.8 23.4 24.0 NS
Site-specific (60-60) Field-average Nontreated LSD(0.05)
74.0 82.8 81.5 3.6
113.3 102.4 105.2 NS
11.6 37.3 17.5 6.8
Site-specific (60-90)z Field-average Nontreated LSD(0.05)
74.1 77.0 83.1 NS
126.9 95.8 99.8 18.2
21.5 14.0 15.9 NS
z
y
Original soil test levels for field average: phosphorus = 26 lb P/acre and potassium = 241 lb K/acre for a corresponding recommended rate of 60-60 lb P2O5-K2O/acre. NS = not significant.
20
PLANT UPTAKE OF ZINC BY SORGHUM IN RESPONSE TO ZINC FERTILIZERS W.F. Johnson, Jr., and R.E. DeLong RESEARCH PROBLEM The objectives of the study were to compare the plant uptakes of zinc (Zn) by sorghum in response to various zinc fertilizers. BACKGROUND INFORMATION Recent reports in Arkansas have detailed the appearance of Zn deficiency symptoms in sorghum grown on loess silt loams. The symptoms of Zn deficiency in sorghum are yellow streaks between the leaf veins, dead areas in older leaves, shortening of internodes, and stunting of the plant. The deficiency symptoms appear on the leaves normally in the early growth stages. A study was initiated in a farmer’s field that had sorghum plants that exhibited foliar symptoms of Zn deficiency, a reduced stand, stunting, and reduced yields in 1999. RESEARCH DESCRIPTION The study was conducted in 2000 in a private farmer’s field in Marmaduke in Greene County on a Collins (Aquic Udifluvent, coarse-silty, mixed, acid, thermic) soil. The experimental design was a randomized complete block with four replications. The treatments were nontreated, a preplant broadcast at 10 lb Zn/acre, a Zn seedcoat at a Low rate at 241 mg Zn/kg seed, a Zn seedcoat at a Medium rate of 356 mg Zn/kg seed, a Zn seedcoat at a High rate of 516 mg Zn/kg seed, an at-emergence banding at 5 lb Zn/acre, an at-emergence banding at 10 lb Zn/acre, and an at-emergence chelate spray at 1 lb Zn/acre. The banded treatments were placed 4 inches parallel from the plant row and 2 inches deep. Soil samples were taken from each plot and dried, ground, extracted with Mehlich III, and analyzed with an inductively coupled argon plasma (ICP) spectrophotometer. The field average for soil test Zn was 6.9 lb/acre. The plots were 9.3 ft wide by 25 ft long with four 28-inch rows. Whole-plant samples were obtained at the 2- and 4-lf stages. Leaves were sampled at full bloom. Plant samples were dried, ground, digested with nitric acid, and analyzed with an ICP. The plots were inadvertently harvested by the cooperating farmer and grain yields were not determined. Soil samples were taken from all the plots at the end of the growing season.
21
AAES Research Series 480
RESULTS No apparent Zn deficiency symptoms such as leaf discoloration or necrosis, stunting, or reduced stands were present in the research plots or in the farmer’s commercial field that surrounded the research plots. Plant Zn uptakes for the whole-plant sampling at the 2- and 4-lf stages and the leaf sampling at heading showed significant differences (Table 1). The plant uptakes for the whole plant sampling at the 2-lf stage showed a range of 0.004 to 0.006 mg Zn/plant, with no significant differences between treatments. The ranges for the whole-plant sampling at the 4-lf stage were 0.05 to 0.09 mg Zn/plant, with the at-emergence banding of five or ten lb Zn/acre treatments were significantly greater than the at-planting seedcoat at the High rate. The plant uptakes for the leaf sampling at the heading stage were 22.3 to 30.0 mg Zn/kg plant, with the preplant broadcast of 10 lb Zn/acre treatment being significantly greater than the at-planting seedcoat of the Low rate. Pearson’s correlation coefficients were determined for the two soil samplings, two whole-plant samplings, and the leaf samplings in comparison to the sorghum Zn uptakes for the seven Zn fertilizer treatments. The coefficients showed significant positive and negative correlations among the test factors, but no consistent trends were evident (data not shown). PRACTICAL APPLICATIONS The absence of the yield data limits the usefulness of the data for a farmer. However, the Zn uptakes by the sorghum illustrated the differences among the Zn fertilizer treatments. The plant uptakes data showed that at the 4-lf stage, the banding of Zn fertilizer at emergence had the highest Zn uptake by sorghum. At heading, the leaf samples showed that the preplant broadcast of Zn treatment had the greatest level of Zn uptake by sorghum. Since the reports of Zn deficiency in farmers’ sorghum fields in 1999 stated that the symptoms normally occurred in the early growth stages of the sorghum, it appears that the at-planting seedcoat at the Medium rate or the atemergence banding of 5 or 10 lb Zn/acre treatments would be the most feasible methods to help control the deficiency. In order to prevent the recurrence of deficiency in the future, a farmer could alternatively apply a preplant broadcast of 10 lb Zn/acre application as a maintenance treatment. The maintenance Zn treatment would also help prevent Zn deficiency symptoms in rice if it is grown in rotation with sorghum. The farmer could choose among the seedcoat, banding, or broadcasting methods, depending on the equipment the farmer utilizes or by calculating which method has the lowest input costs. Further studies need to be conducted concerning various Zn fertilizer treatments, the plant Zn uptakes, grain yields, and using a variety of sorghum cultivars in sites that have shown sorghum Zn deficiency symptoms in the past. ACKNOWLEDGMENT Financial support from the Arkansas Fertilizer Tonnage Fee is appreciated.
22
Arkansas Soil Fertility Studies 2000
Table 1. Interaction of zinc (Zn) fertilizers on plant Zn uptakes on sorghum, Farm in Marmaduke, Arkansas, 2000. Plant Zn Uptake Fertilizer Treatment lb Zn/acre
Whole - 2-lf Stage
---------------------- mg/plant ---------------------
Nontreated Preplant broadcast - 10 Plant seedcoat low ratez Plant seedcoat medium rate Plant seedcoat high rate Emergence band - 5 Emergence band - 10 Emergence broadcast chelate - 1 LSD(0.05) z
Whole - 4-lf Stage
0.004 0.004 0.005 0.006 0.005 0.004 0.004 0.004 NS
0.07 0.07 0.07 0.08 0.05 0.09 0.09 0.07 0.03
Leaf - Head Stage mg/kg 26.0 30.0 22.3 27.8 24.8 28.7 27.4 26.4 5.7
Seedcoat rates are relative amounts where Low = 241, Medium = 356, and High = 516 mg Zn/kg seed.
23
AAES Research Series 480
INFLUENCE OF PHOSPHORUS FERTILIZER ON PHOSPHORUS UPTAKES AND GRAIN YIELDS OF WHEAT FOLLOWING RICE R.E. DeLong, W.F. Johnson, Jr., and M.D. Correll RESEARCH PROBLEM The objectives of the study were to determine the phosphorus (P) uptakes and grain yields of wheat when different P fertilizer rates were applied to wheat cultivars cropped to a field previously in rice. BACKGROUND INFORMATION Phosphorus fixation in a reoxidizing rice soil is progressive, thereby removing available P from the soil solution as both time and redox cycles increase. When rice is the first crop in a rice-wheat rotation, the availability of soil P for wheat uptake can be reduced. The application of different P fertilizer rates to a wheat field that was previously cropped to rice would help determine the effects of rice on the amount of available soil P for the wheat. The measurements of P uptakes by wheat and grain yields would help determine the effects on wheat grown in a site that was previously cropped to rice. RESEARCH DESCRIPTION The study was planted at the Pine Tree Branch Experiment Station at Colt on a Calhoun (Typic Glossaqualfs, fine-silty, mixed, thermic) soil on 6 October 1999. The plots were 5 ft wide by 20 ft long with 7-inch wide rows. The experimental design was a randomized complete block with four replications. Phosphorus fertilizer (0-46-0) was applied before planting wheat on a field cropped to rice in 1999. The fertilizer was broadcast and incorporated before planting. The P fertilizer rates were 0, 15, 30, and 45 lb P2O5/A. The cultivars included were AgriPro Patton, AgriPro Shelby, AgriPro Shiloh, AR 494B-2-2, AR 584A-3-1, AR 656-5-1, FFR522W, NK Coker 9663, Pioneer 2684, and Terral TV8555. Spring nitrogen rates were applied at the recommended rates and times. Whole-plant samples were taken at heading on 13 April 2000 to determine plant nutrient uptakes. The plant samples were dried, weighed, ground to pass a 1 mm-sieve, digested with nitric acid, and analyzed in the laboratory with an inductively coupled argon plasma spectrophotometer. The stand condition was good and was successfully harvested on 14 June 2000. Data from the plant nutrient uptakes and grain yields were statistically analyzed using the software program SAS.
24
Arkansas Soil Fertility Studies 2000
RESULTS Significant differences in plant P uptake for the cultivars at all P fertilizer rates were evident (Table 1). The plant P uptake ranges for the 0, 15, 30, and 45 lb P2O5/ acre fertilizer rates were 5.7 to 12.7, 6.6 to 14.2, 7.3 to 14.5, and 6.6 to 16.3 mg/plant, respectively. AgriPro Shelby had the greatest uptake in three of the four P fertilizer rates. AgroPro Shiloh and Terral TV8555 were significantly lower in two of the four P fertilizer rates compared to the highest cultivars. As the P fertilizer rates increased, there were one, three, and four cultivars significantly lower than the same cultivar at the 0, 15, 30, and 45 P fertilizer rates, respectively. Significant differences in grain yields for the cultivars at all P fertilizer rates were evident (Table 2). The grain yield ranges for the 0, 15, 30, and 45 lb P2O5/acre fertilizer rates were 8.7 to 46.5, 16.5 to 38.0, 16.9 to 39.5, and 21.5 to 43.3 bu/acre, respectively. AgriPro Shelby had more stable grain yields than the other cultivars at all four P fertilizer rates. AgriPro Patton, AgriPro Shiloh, AR 656-5-1, and Terral TV8555 had the lowest yields over all four P fertilizer rates compared to the other cultivars. FFR522W was the highest overall yielding cultivar at the 30 lb P2O5/acre fertilizer rate and second at the other three P fertilizer rates. PRACTICAL APPLICATIONS Significant differences in plant P uptakes and grain yields among the cultivars illustrated that there were great differences in the cultivar’s responses to various P fertilizer rates. Farmers could utilize the data to select the most appropriate cultivar that best suits their P fertilizer input plans when wheat follows rice. Further studies need to address the interactions of a variety of cultivars on various soils at multiple P fertilizer rates in different crop rotations to more efficiently determine the response of wheat in different growing conditions. ACKNOWLEDGMENT Financial supports from the Arkansas Wheat Promotion Board and the Arkansas Fertilizer Tonnage Fee are appreciated.
25
AAES Research Series 480
Table 1. Interaction of cultivars, phosphorus (P) fertilizer rates, and plant P uptakes at heading on wheat following rice, Pine Tree Branch Experiment Station, Colt, Arkansas, 1999-2000. Phosphorus fertilizer rate (lb P2O5/acre) Cultivar
0
15
30
45
---------------------------------- mg/plant ----------------------------------AgriPro Patton AgriPro Shelby AgriPro Shiloh AR 494B-2-2 AR 584A-3-1 AR 656-5-1 FFR522W NK Coker 9663 Pioneer Var. 2684 Terral TV8555 LSD(0.05)
10.0 12.7 9.3 10.3 7.6 9.4 9.0 12.2 11.6 5.7 5.2
8.6 14.2 6.6 10.7 11.4 8.8 9.4 10.0 8.6 9.8 7.2
10.2 7.6 14.5 9.2 10.6 8.6 7.3 12.6 10.3 8.3 6.2
8.5 16.3 6.6 9.8 9.4 11.4 15.5 11.5 12.5 11.5 5.8
Table 2. Interaction of cultivars, phosphorus (P) fertilizer rates, and wheat grain yields on wheat following rice, Pine Tree Branch Experiment Station, Colt, Arkansas, 1999-2000. Phosphorus fertilizer rate (lb P2O5/acre) Cultivar AgriPro Patton AgriPro Shelby AgriPro Shiloh AR 494B-2-2 AR 584A-3-1 AR 656-5-1 FFR522W NK Coker 9663 Pioneer Var. 2684 Terral TV8555 LSD(0.05)
26
0 15 30 45 ----------------------------------- bu/acre ----------------------------------19.6 46.5 19.6 26.6 29.8 26.1 33.2 22.0 28.3 8.7 12.9
21.8 27.1 21.5 27.8 38.0 19.6 36.8 32.7 24.5 16.5 15.1
16.9 30.5 19.6 32.0 24.7 21.5 39.5 23.0 30.7 17.4 16.6
21.5 31.0 26.4 26.9 43.3 27.1 42.1 30.3 29.0 26.1 16.1
AGRONOMICS OF FIELD-AVERAGE OR SITE-SPECIFIC APPLICATIONS OF PHOSPHORUS AND POTASSIUM FERTILIZERS ON WHEAT R.E. DeLong, W.F. Johnson, Jr., M.D. Correll, and W.E. Sabbe
RESEARCH PROBLEM Our objectives were to determine the grain yields and uptakes of phosphorus (P) and potassium (K) by wheat as affected by the application of P and K fertilizers with field-average or site-specific application methods. BACKGROUND INFORMATION The advent of site-specific agriculture, with its inclusion of monitoring yields on small areas, allows for the application of fertilizer via variable rate technology. Prior to the use of site-specific techniques, the goal of soil sampling was to obtain a sample that contained the mean values of a field. Traditionally, fertilizer was applied to an entire field based on the average of one bulked soil sample. Site-specific agriculture allows for numerous types of fertilizer and application rates within a field based on the soil analyses for each specific area of a field. The crop response must also be documented as to nutrient uptakes to facilitate the timing and rates of fertilizer applications. RESEARCH DESCRIPTION The study crop was planted at the Arkansas Research and Extension Center at Fayetteville on a Captina (Typic Fragiudults, fine-silty, mixed, thermic) soil in October of 1997, 1998, and 1999. The field average for the soil test P was 32 lb/acre and K was 182 lb/acre, with the corresponding recommended fertilizer rates of 60 lb P2O5/acre and 30 lb K2O/acre. The fertilization rates for the site specific areas were 80-0, 90-0, 100-0, 40-30, 80-30, 90-30, 100-30, 80-60, 90-60, and 100-60 lb P2O5-K2O/acre, respectively. Phosphorus and K fertilizers were applied broadcast and incorporated before planting. Each block that was originally soil sampled was 13.4 ft wide by 30 ft long. The four quarters of the block received either no fertilizer, the recommended rate for the field average, 2 times the field average, or site-specific for the block’s soil test level. The final plots were 6.7 ft wide by 15 ft long with 7-inch wide rows. The experimental design was a randomized complete block. Spring nitrogen was applied at the recommended rate and time. Whole-plant samples were taken at heading and the plant nutrient uptakes were determined. The plant samples were dried, weighed, ground to pass a 1-mm sieve, digested with nitric acid, and analyzed in the laboratory with an inductively coupled argon plasma (ICP) spectrophotometer. The plots were successfully harvested at plant maturity
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in June of every year. Data from the plant nutrient uptakes and grain yields were statistically analyzed with the software program SAS. RESULTS Fertilizer treatments and fertilizer placement methods had a significant impact on grain yields and P uptakes in 1997-1998 (Table 1). The grain yields ranged from 23.7 to 29.2 and 28.1 to 33.3 bu/acre for the fertilizer treatments 100-0 and 40-30 lb P2O5-K2O/ acre, respectively. Significant differences were present for the P, and none for K, plant uptakes at the 80-0, 90-0, 40-30, 80-30, and 100-30 P-K fertilizer treatments. Fertilizer treatments and fertilizer placement methods had a significant impact on grain yields and P and K uptakes in 1998-1999 (Table 2). The grain yield ranges (in bu/acre) were as follows: 36.5 to 42.2 (90-0 lb P2O5-K2O/acre), 29.7 to 39.9 (100-0 lb P2O5-K2O/acre), 34.7 to 38.9 (90-30 lb P2O5-K2O/acre), and 31.3 to 37.1 (100-30 lb P2O5-K2O/acre). Significant differences were present for P plant uptakes at the 80-0, 90-0, 100-0, 90-30, 100-30, and 100-60 P-K fertilizer treatments. Significant differences were present for the K plant uptakes at the 80-0 P-K fertilizer treatment. Fertilizer treatments or fertilizer placement methods did not have a significant impact on grain yields, but they did on P and K uptake rates in 1999-2000 (Table 3). The grain yield ranges (in bu/acre) were as follows: 35.1 to 37.3 (80-0), 32.9 to 35.7 (90-0 lb P2O5-K2O/acre), 27.1 to 31.1 (100-0 lb P2O5-K2O/acre), 28.8 to 30.9 (40-30 lb P2O5-K2O/acre), 30.8 to 35.6 (80-30 lb P2O5-K2O/acre), 32.2 to 34.7 (90-30 lb P2O5K2O/acre), 27.9 to 29.3 (100-30 lb P2O5-K2O/acre), 33.5 to 39.7 (80-60 lb P2O5-K2O/ acre), 35.6 to 40.6 (90-60 lb P2O5-K2O/acre), and 28.1 to 30.7 (100-60 lb P2O5-K2O/ acre). Significant differences were present for P plant uptakes at the 80-0, 100-0, 9030, and 90-60 P-K fertilizer treatments. Significant differences were present for the K uptakes at the 80-0, 100-0, 80-30 and 90-60 P-K fertilizer treatments. PRACTICAL APPLICATIONS The fertilizer treatments or fertilizer placement methods affected the grain yields and P and K plant uptake rates. At two of the P-K rates in the first year and three of the P-K rates in the second year of the study, the yield of the fertilized plots were significantly greater than the nontreated plots. The 100-0 P-K rate of fertilizer helped increase the grain yields and P uptake rates in two of the three years and the K uptake rates in one year. There appeared to be no distinct differences among the fertilizer treatment methods. A farmer could use these data to help determine whether applying P and K fertilizers to wheat that followed rice may help increase P and K uptake rates or grain yields. Further research will need to be conducted to determine the effect of various fertilizer treatments applied in traditional or site-specific methods on wheat in different soils and cropping rotations.
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ACKNOWLEDGMENT Financial supports from the Arkansas Wheat Promotion Board and the Arkansas Fertilizer Tonnage Fee are appreciated.
Table 1. Influence of phosphorus (P) and potassium (K) fertilizers applied by field-average or site-specific methods on wheat grain yields and plant uptakes of P and K at heading, Arkansas Agricultural Research and Extension Center, Fayetteville, Arkansas, 1997-1998. Plant uptake at heading Fertilizer Placement Method lb P2O5-K2O/acre Nontreated Field-averagez Field-average X2 Site-specific (80-0) LSD(0.05) Nontreated Field-average Field-average X2 Site-specific (90-0) LSD(0.05) Nontreated Field-average Field-average X2 Site-specific (100-0) LSD(0.05) Nontreated Field-average Field-average X2 Site-specific (40-30) LSD(0.05) Nontreated Field-average Field-average X2 Site-specific (80-30) LSD(0.05) Nontreated Field-average Field-average X2 Site-specific (90-30) LSD(0.05) Nontreated Field-average Field-average X2 Site-specific (100-30) LSD(0.05)
Grain yield bu/acre 36.6 33.9 37.7 34.3 NSy 34.2 34.4 34.7 32.2 NS 23.7 25.9 29.2 28.0 4.9 28.1 33.3 33.0 29.7 2.4 33.5 35.4 35.3 37.3 NS 30.5 30.1 30.1 30.0 NS 25.2 26.9 27.9 28.1 NS
P
K
------ mg/plant -----13.9 19.5 20.4 18.1 5.1 14.1 18.8 21.3 18.2 4.1 11.8 13.4 14.9 15.3 NS 11.1 18.3 12.6 14.7 5.5 15.0 19.5 19.7 18.2 2.8 14.5 15.1 15.9 17.9 NS 9.5 11.1 13.0 14.2 2.6
108.7 127.4 123.7 119.7 NS 110.0 123.9 123.7 105.1 NS 91.3 100.8 99.0 93.6 NS 91.1 106.8 84.8 98.6 NS 104.9 123.0 118.6 112.3 NS 99.7 96.7 102.5 108.2 NS 87.0 91.8 94.5 102.0 NS continued
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Table 1. Continued. Plant uptake at heading Fertilizer Placement Method lb P2O5-K2O/acre Nontreated Field-average Field-average X2 Site-specific (80-60) LSD(0.05) Nontreated Field-average Field-average X2 Site-specific (90-60) LSD(0.05) Nontreated Field-average Field-average X2 Site-specific (100-60) LSD(0.05) z
y
Grain yield bu/acre 34.6 32.5 39.6 35.2 NS 38.3 35.7 35.9 34.9 NS 27.8 30.0 30.0 29.7 NS
P
K
------ mg/plant -----23.1 18.9 26.2 25.8 NS 18.6 18.4 18.3 17.7 NS 12.6 15.3 13.1 13.0 NS
143.5 113.2 174.0 144.3 NS 127.7 120.4 119.7 111.6 NS 107.5 103.6 104.4 93.2 NS
Recommended rate of 60 lb P2O5/acre and 30 lb K2O/acre from field average of all soil samples. NS = not significant.
Table 2. Influence of phosphorus (P) and potassium (K) fertilizers applied by field-average or site-specific methods on wheat grain yields and plant uptakes of P and K at heading, Arkansas Agricultural Research and Extension Center, Fayetteville, Arkansas, 1998-1999. Plant uptake at heading Fertilizer Placement Method lb P2O5-K2O/acre Nontreated Field-average Nontreated Field-averagez Field-average X2 Site-specific (80-0) LSD(0.05) Nontreated Field-average Field-average X2 Site-specific (90-0) LSD(0.05) Nontreated Field-average Field-average X2 Site-specific (100-0) LSD(0.05)
Grain yield bu/acre 34.6 32.5 36.1 39.4 41.3 41.9 NSy 36.5 38.0 38.4 42.2 5.5 29.7 35.6 39.9 36.6 4.4
P
K
------ mg/plant -----23.1 18.9 12.2 17.8 20.2 18.2 4.5 12.2 15.4 18.0 15.4 3.6 10.2 11.7 11.8 14.4 3.8
143.5 113.2 117.9 137.0 158.9 135.5 39.8 109.3 130.6 142.7 121.1 NS 96.5 102.1 94.9 108.1 NS continued
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Table 2. Continued. Plant uptake at heading Fertilizer Placement Method lb P2O5-K2O/acre Nontreated Field-average Field-average X2 Site-specific (40-30) LSD(0.05) Nontreated Field-average Field-average X2 Site-specific (80-30) LSD(0.05) Nontreated Field-average Field-average X2 Site-specific (90-30) LSD(0.05) Nontreated Field-average Field-average X2 Site-specific (100-30) LSD(0.05) Nontreated Field-average Field-average X2 Site-specific (80-60) LSD(0.05) Nontreated Field-average Field-average X2 Site-specific (90-60) LSD(0.05) Nontreated Field-average Field-average X2 Site-specific (100-60) LSD(0.05) z
y
Grain yield bu/acre 36.0 39.6 39.0 36.0 NS 45.6 37.7 41.3 40.8 NS 35.8 38.6 34.7 38.9 3.5 31.3 35.7 37.1 36.6 3.5 36.7 37.9 39.0 40.3 NS 36.5 39.6 34.9 38.8 NS 36.9 39.4 38.8 36.5 NS
P
K
------ mg/plant -----14.7 17.5 17.5 15.5 2.6 16.9 16.2 18.8 19.2 NS 11.8 13.9 14.8 14.3 2.1 9.6 12.3 13.5 15.2 2.2 25.1 20.5 24.3 18.6 NS 15.2 16.3 19.0 17.8 NS 12.1 15.5 17.5 15.5 5.4
114.6 125.2 135.7 119.8 NS 145.7 141.3 152.6 155.3 NS 111.5 126.1 122.2 118.2 NS 106.1 106.3 111.2 121.9 NS 192.2 159.7 179.2 152.6 NS 149.3 139.4 145.6 164.4 NS 118.2 129.9 140.1 123.0 NS
Recommended rate of 60 lb P2O5/acre and 30 lb K2O/acre from field average of all soil samples. NS = not significant.
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Table 3. Influence of phosphorus (P) and potassium (K) fertilizers applied by field-average or site-specific methods on wheat grain yields and plant uptakes of P and K at heading, Arkansas Agricultural Research and Extension Center, Fayetteville, Arkansas, 1999-2000. Plant uptake at heading Fertilizer Placement Method lb P2O5-K2O/acre Nontreated Field-averagez Field-average X2 Site-specific (80-0) LSD(0.05) Nontreated Field-average Field-average X2 Site-specific (90-0) LSD(0.05) Nontreated Field-average Field-average X2 Site-specific (100-0) LSD(0.05) Nontreated Field-average Field-average X2 Site-specific (40-30) LSD(0.05) Nontreated Field-average Field-average X2 Site-specific (80-30) LSD(0.05) Nontreated Field-average Field-average X2 Site-specific (90-30) LSD(0.05) Nontreated Field-average Field-average X2 Site-specific (100-30) LSD(0.05) Nontreated Field-average Field-average X2 Site-specific (80-60) LSD(0.05)
Grain yield bu/acre 35.1 37.3 36.9 36.5 NSy 34.8 35.7 32.9 34.5 NS 27.2 29.4 31.1 29.9 NS 30.5 30.0 30.9 28.8 NS 35.1 30.8 35.6 35.1 NS 33.6 34.7 32.2 34.1 NS 29.3 28.0 27.9 29.0 NS 39.7 39.5 33.5 34.5 NS
P
K
------ mg/plant -----11.9 11.8 12.6 16.3 3.9 15.2 14.2 14.2 14.0 NS 16.0 15.2 13.5 13.8 2.1 14.6 14.4 13.6 12.9 NS 13.9 13.2 14.0 10.9 NS 12.8 14.0 15.0 15.5 2.0 13.2 14.2 13.9 13.7 NS 11.1 13.4 9.6 10.1 NS
134.3 122.2 141.7 172.0 37.2 171.1 165.2 165.7 154.4 NS 154.2 163.9 130.2 134.6 26.9 156.5 158.6 159.9 151.5 NS 156.5 140.6 151.6 122.6 33.9 139.8 148.5 156.6 156.2 NS 142.5 155.7 152.9 149.6 NS 131.5 156.4 133.1 134.0 NS continued
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Table 3. Continued. Plant uptake at heading Fertilizer Placement Method lb P2O5-K2O/acre Nontreated Field-average Field-average X2 Site-specific (90-60) LSD(0.05) Nontreated Field-average Field-average X2 Site-specific (100-60) LSD(0.05) z y
Grain yield bu/acre 35.6 36.0 36.6 40.6 NS 29.1 30.7 28.1 30.2 NS
P
K
------ mg/plant -----10.0 9.0 13.6 14.6 4.8 10.8 11.6 11.7 13.4 NS
113.0 116.7 162.2 151.2 43.3 129.0 133.9 143.8 157.0 NS
Recommended rate of 60 lb P2O5/A and 30 lb K2O/A from field average of all soil samples. NS = not significant.
33
TEMPORAL VARIABILITY OF SOIL PHOSPHORUS IN PASTURES AMENDED WITH ANIMAL MANURE M.B. Daniels, S.L. Chapman, J. Gunsaulis, K. Teague, and K. Combs
RESEARCH PROBLEM Little information exists on the in-field, temporal variability of soil test phosphorus (STP) in Arkansas pastures. The objective of this study was to characterize the seasonal variability of STP in pastures. BACKGROUND INFORMATION Soil test phosphorus (P) levels of pastures amended repeatedly over the years with animal manure has become a serious issue for livestock producers (Daniels et al., 1998). Concerns over P-laden runoff from pastures has prompted interest in establishing environmental thresholds based on STP for governing future manure applications (USDA, 1999). In-field spatial variability of STP may make it difficult to characterize a pasture with a single value for comparison to an environmental threshold (Daniels et al., 2000a). Little is known about the effect of temporal variation in STP on obtaining a reliable estimate. RESEARCH DESCRIPTION Soil samples were collected in a grid pattern in three pastures (RV1, OH1, and OH2) in May 1999 and again in November 1999 to determine the spatial and temporal variability of STP. Livestock grazed the pastures, but no additional P was added between sampling dates. A real-time differential global positioning system (GPS) unit was used to mark and return to each original grid point in May and November, respectively. Individual samples were collected at each grid point by combining four 6-inch-deep sub-samples collected with a 3-inch-diameter bucket auger. Sub-samples were collected in a circular area within a 3-ft radius of the grid point for both sampling times. Samples were submitted to the University of Arkansas Soil Test Lab at Marianna for routine analysis. The relative change (%) in STP was calculated as ((STPFall – STPSpring)/ STPSpring) * 100. RESULTS Mean soil P levels were not significantly different from May to November in any of the fields, although the mean was numerically greater in November in each pasture (Table 1). However, relative changes in STP (both increases and decreases) were observed at individual grid locations (Figures 1, 2, and 3). These changes resulted in
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differences in the distribution of percentage of pasture area in different soil P ranges May to November (Table 2). PRACTICALAPPLICATIONS The University of Arkansas currently recommends sampling fields at least every 3 years during the same time of year (Daniels et al., 2000b). These results indicate that seasonal differences in STP can occur and support the recommendation to sample during the same time of year or season. Because both increases and decreases were observed in each field, little information about which season, spring or fall, is the more appropriate can be gleaned from these data. Consistency in sampling with respect to season is an important consideration in the building of historical soil test databases. LITERATURECITED Daniels, M.B., T.C. Daniel, D. Carman, R. Morgan, J.M. Langston, and K. VanDevender. 1998. Soil phosphorus levels: concerns and recommendations. 1999. In: Proceedings 1998 National Poultry Waste Management Symposium. Daniels, M.B., P. Delaune, P.A. Moore, Jr., A. Mauromoustakos, S.L. Chapman, and J.M. Langston. 2000a. Soil phosphorus variability in pastures: implications for sampling and environmental management strategies. J. Environ. Qual. (Submitted) Daniels, M.B., J.M. Langston, S.L. Chapman, K. Combs, K. VanDevender, and J. Jennings. 2000b. Soil Testing for Manure Management. University of Arkansas Cooperative Extension Service. Publication FSA1035. U.S. States Department of Agriculture and the U.S. Environmental Protection Agency. 1999. Unified National Strategy for Animal Feeding Operations. March 9, 1999.
Table 1. Mean soil phosphorus in pastures sampled in May and again in November 1999. May Pasture
Nz
RV1 OH1 OH2
26 18 20
Mean
s.d.y
November Mean s.d.
----------------------------- lb/acre -----------------------------
z y
266 852 444
128 102 102
296 874 518
126 118 134
N = number of samples. s.d. = standard deviation.
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Table 2. Pasture area (%) in soil phosphorus categories for three pastures. STP Z Category lb/acre 0-100 101-200 201-300 301-400 401-500 501-600 601-700 701-800 801-900 901-1000 Z
RV1 May
OH1
November
May
OH2
November
May
November
---------------------------------------------- % -------------------------------------------4 21 55 8 7 5 – – – –
4 18 38 28 7 5 – – – –
– – – – – – – 23.4 53.2 23.4
– – – – – – – 23.4 40.4 36.2
– – 1.9 30.7 42.3 23.2 1.9 – – –
– – 5.8 13.5 34.6 25.0 21.1 – – –
STP = soil test phosphorus.
Fig. 1. Map of soil phosphorus and percentage of relative change in pasture RV1. Large numbers outside of pasture boundary are soil phosphorus contour levels, while smaller numbers are the percentage of relative change from May to November for each individual grid point.
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Arkansas Soil Fertility Studies 2000
Fig. 2. Map of soil phosphorus and percentage of relative change in pasture OH1. Large numbers outside of pasture boundary are soil phosphorus contour levels, while smaller numbers are the percentage of relative change from May to November for each individual grid point.
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Fig. 3. Map of soil phosphorus and percentage of relative change in pasture OH2. Large numbers outside of pasture boundary are soil phosphorus contour levels, while smaller numbers are the percentage of relative change from May to November for each individual grid point.
38
A NEW APPROACH TO LIME RECOMMENDATIONS IN ARKANSAS John Gilmour and Paula Anderson RESEARCH PROBLEM Crop yield response to lime has been difficult to document in Arkansas. Possible reasons are that crop yield response versus soil pH is not known, soil sample pH is different from soil pH during the growing season, and/or the lime recommendation is incorrect. The objectives of this study were to develop a simple method of estimating lime requirements for Arkansas’ soils and to understand the impact of antecedent weather and soil conditions on soil pH. BACKGROUND INFORMATION There is evidence that row crops such as soybean and cotton respond to lime (Adams, 1984), that soil pH does vary over time (Adams, 1984; Gilmour, J.T., unpublished data), and that the current method of making lime recommendations needs improvement (McConnell et al., 1991). RESEARCH DESCRIPTION Soil samples with low pH were obtained from the Eastern Arkansas Soil Testing Laboratory. Soils were combined by soil association and by calcium and magnesium content. Sixteen groups shown in Table 1 were selected for buffer curve and cation exchange capacity (CEC) determination (McConnell et al., 1991). The impact of soil moisture (50% water holding capacity, WHC; and flooded), temperature (59ϒC, 3 days frozen and 4 days at 59ϒC), and organic matter addition (+/– rice straw at 10 dry tons/ acre) was tested in a complete factorial experiment where soil pH (1:2, soil:water ratio) was measured initially and at 1, 2, and 4 weeks prior to drying the soil. The effect of drying the soil at room temperature on soil pH was tested on all samples at 4 weeks. All statistics were done using SAS JMP version 3.1.5. RESULTS The soil CEC determined experimentally (CECpH7) was significantly related to CEC calculated by the Soil Test Lab (CECcal), CECpH7 = 1.6 +0.89 H CECcal (r2 = 0.45) with the intercept not significantly different from zero. The slope of the buffer curve (S) was significantly related to the CECpH7 in an inverse relationship (1 ÷ S = 5454 –19333 ÷ CECpH7, r2 = 0.76). Soil pH was increased by incubation at 50% WHC or flooding (Table 2), but the increases were small unless organic matter (OM, rice straw) had been added. The addi-
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tion of OM (Table 2) also increased initial pH values as described by Pocknee and Sumner (1997). The pH increases were smaller when the soil was dried prior to pH measurement, but drying did not eliminate the effect. PRACTICALAPPLICATIONS Lime recommendations in Arkansas using the relationships presented herein appear to offer a more direct measure of lime needs than the current method. Actual pH of field moist soil is likely different than that measured in the laboratory if soils are sampled wet or recently have been amended with crop residues containing basic cations (Pocknee and Sumner, 1997). LITERATURECITED Adams, F. 1984. Crop response to lime in the southern United States. In: Adams, F. (ed.). Soil Acidity and Liming. 2nd Edition. Agronomy Monograph 12. American Society of Agronomy, Madison, Wisconsin. McConnell, J.S., J.T. Gilmour, R.E. Baser, and B.S. Frizzell. 1991. Lime requirement of acid soils of Arkansas. 1991. Univeristy of Arkansas Agricultural Experiment Station Special Report 150. Pocknee, S. and M.E. Sumner. 1997. Cation and nitrogen contents of organic matter determine its soil liming potential. Soil Sci. Soc. Amer. J. 61: 86-92.
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Arkansas Soil Fertility Studies 2000
Table 1. Selected properties of soil groups. Soil Assoc.
Samples z
22 22 24 25 26 29 29 32 44 44 44 45 45 46 47 47 z y x w v
3 2 1 2 2 1 1 2 3 15 6 3 8 2 5 3
pH y
Potassium
Calcium
1:2
------------------- lb/acre -----------------
cmol +/kg
4.8 4.9 4.7 4.4 4.5 4.6 4.1 4.3 4.5 4.4 4.8 4.2 4.7 4.6 4.8 4.5
210 110 460 240 280 1000 800 220 240 160 190 340 390 70 140 270
8 10 18 6 7 13 10 7 8 6 9 6 8 6 8 9
1040 1500 2710 500 620 2330 1430 540 1040 560 1070 500 1020 510 950 1100
Magnesium Sodium CEC x CEC w 280 400 1210 30 110 140 170 140 180 120 530 100 230 120 210 560
110 100 160 80 90 120 120 100 110 100 140 100 110 120 110 120
7.3 8.7 23.3 3.4 6.3 14.3 17.7 5.5 7.7 7.9 11.3 9.2 8.2 5.8 6.2 13.6
Buffer curve slope v 0.00052 0.00042 0.00020 0.00128 0.00065 0.00024 0.00019 0.00067 0.00027 0.00032 0.00031 0.00023 0.00036 0.00060 0.00043 0.00024
Number of equal weight samples combined. Soil pH was determined on a 1:2, soil:water ratio. Cation exchange capacity reported by the Soil Testing Lab. Cation exchange capacity determined experimentally. pH/ ton CaCO3/acre where CaCO3 has a 100% effective calcium carbonate equivalence (ECCE). ECCE corrects each liming material for purity and fineness.
Table 2. Average effect of soil moisture, soil temperature, and organic matter (OM) on soil pH for the soils studied. Soil pH z after incubation for Moisture
Temperature
OMy
0 wk
1 wk
2 wk
4 wk x
– – + – – +
4.8 4.8 5.2 4.8 4.8 5.2
5.1 5.1 5.3 5.1 5.2 5.5
5.1 5.1 5.4 5.1 5.2 5.8
5.2 5.2 5.6 5.2 5.3 6.0
LSD0.05w
ϒF 50% WHCv
Flooded
z y x
w v
32 then 59 59 59 32 then 59 59 59
0.1 0.1 0.2 0.2 0.1 0.3
Soil not dried prior to pH measurement; 1:2, soil:water ratio. OM = organic matter added (+) as rice straw at 10 dry tons/acre. Values of soil pH for soil dried prior to pH measurement down this column were 5.1, 5.1, 5.4, 5.2, 5.3, and 5.6, respectively. Least significant difference for pH values in a given row. Water holding capacity.
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CROP YIELDS VERSUS SOIL TEST VALUES USING GPS/GIS TECHNOLOGY J.T. Gilmour, L.R. Fry, and N.A. Slaton RESEARCH PROBLEM Grid sampling of soils has been a focal point of precision agriculture. The objective of this study was to determine whether relationships exist between rice and soybean yields and routine soil test data obtained from the same location as the yield sample. BACKGROUND INFORMATION The study was located on a 2400-acre farm in the Bayou de View watershed in Monroe County. Slightly over 2200 acres were under cultivation in a 1:2 rice:soybean rotation, with approximately one-half of the soybean fields double-cropped with winter wheat each year. RESEARCH DESCRIPTION The top 6 inches of soil was sampled, or to the plow pan (~4 inches) if one was present. Numbered 2-acre squares, 295 ft on a side, were created and then sub-divided into 25 equal sub-grids using GPS/GIS technology. One of the sub-grids in each square was randomly chosen for composite soil sampling. Soil sampling was begun in late February 1999 and completed in mid-May 1999. Nearly 700 soil samples were collected. All samples were subjected to the routine soil test at the Eastern Arkansas Soil Test Laboratory. The 1998 and 1999 yield data were collected in JDMap/GREENSTAR® by the farm manager during harvest. RESULTS Forty-nine percent of the soil at the farm was Grubbs silt loam that has medium natural fertility, very slow permeability, and high available water capacity. Thirty-three percent of the soil at the farm was Jackport silty clay loam that has medium natural fertility, very slow permeability, and high available water capacity. Fifteen percent of the soil at the farm was Crowley silt loam that has medium natural fertility, very slow permeability, and high available water capacity. Rice yields in 1998 were measured for 46% of the demonstration farm and averaged 139 bu/acre. Rice yields in 1999 were measured for 37% of the demonstration farm and averaged 136 bu/acre. Soybean yields in 1999 were measured for 54% of the demonstration farm and averaged 29 bu/acre. Soil pH varied from about 5.5 to nearly 8.0 over the three crop/year combinations. No consistent pH effect on rice yield was found (Fig. 1). However, soybeans showed a slight yield increase with increasing soil pH values above 7.0. No relationship between
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Arkansas Soil Fertility Studies 2000
yield and soil test calcium was found (Fig. 2). Exchangeable sodium percentages (ESP) varied from about 1.0 to 7.0%. Yields of rice and soybean were not affected over this range of ESP (Fig. 3). Soil test phosphorus (P) ranged from slightly less than 20 to nearly 100 lb/acre, but there were no yield decreases at low soil test P values (Fig. 4). Soil test potassium (K) ranged from about 125 to nearly 500 lb/acre. No relationship was found between soil test K and rice yield (Fig. 5). Soybeans showed a decrease in yield with increasing soil test K levels above 150 lb/acre. PRACTICALAPPLICATIONS These data characterize the range of soil test values where rice or soybean yield increases or decreases from fertilization, liming, or acidification are not likely. In general, the data agree with published values for Arkansas (Slaton et al, 1994; Snyder et al., 1994) REFERENCES Slaton, N., R.J. Norman, B.R. Wells, D.M. Miller, R. Helms, C.A. Beyrouty, and C. Wilson. 1994. Efficient use of fertilizer. In: R.S. Helms (ed.). Rice Production Handbook. University of Arkansas Cooperative Extension Service. MP 192. Little Rock. pp. 42-54. Snyder, C.S. and W.E. Sabbe. 1994. Cost-effective liming and fertilization of soybeans. In: Technology for Optimum Soybean Production. University of Arkansas Cooperative Extension Service. AG411-12-94. Little Rock.
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Fig. 1. Rice and soybean yields versus soil pH.
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Arkansas Soil Fertility Studies 2000
Fig. 2. Rice and soybean yields versus soil test calcium.
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Fig. 3. Rice and soybean yields versus soil exchangeable sodium percentage (ESP).
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Fig. 4. Rice and soybean yields versus soil test phosphorus.
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Fig. 5. Rice and soybean yields versus soil test potassium.
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Arkansas Soil Fertility Studies 2000
CORN RESPONSE TO PHOSPHORUS AND POTASSIUM FERTILIZATION AT VARIOUS SOIL TEST LEVELS J. H. Muir and J. A. Hedge RESEARCH PROBLEM Modern corn hybrids, more intensive management systems, and crop rotations not previously used may result in different phosphorus (P) and potassium (K) requirements than required in years past. Studies on nitrogen requirements for corn in Arkansas in the 1980s identified a need to modify nitrogen recommendations for modern hybrids on finertextured soils (Muir et al., 1992). These studies were initiated in 1997 to evaluate the response of corn to P and K fertilization on a range of soil test P and K levels. BACKGROUND INFORMATION Phosphorus and K recommendations for corn based on studies conducted years ago may not be adequate for corn grown in current production systems. Calibration studies to confirm current P and K recommendations or to provide evidence for modifying recommendations were warranted. RESEARCH DESCRIPTION Phosphorus and K calibration studies were initiated on a Calloway silt loam soil at Arkansas State University, Jonesboro. Sites with a range of soil P and K levels were located in order to impose fertilizer treatments on blocks of varying soil test levels. Both sites had a range of soil K levels but had a limited soil P range. Soil K levels ranged from 85 to 272 lb/acre, and soil P ranged from 17 to 50 lb/acre. Phosphorus and K fertilizer rates of 0, 0.5, 1.0, and 2.0 times the recommended rate for the lowest soil test levels were broadcast and incorporated before planting each year. RESULTS Application of K increased corn grain yield on soils with low, moderately low, and medium K soil test levels in 1998 and 1999, and at low and moderately low levels in 2000 (Table 1). There was a yield response to applied P in 1998 and 1999 on soils with low P soil test levels and in 1999 on soils with medium soil test values for P (Table 2). By fall 1999, P soil test levels were very similar in plots initially low and medium in P. Although there was not a significant difference in yields due to applied P, there was a trend increased yield with increased applied P rates (Table 3).
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PRACTICALAPPLICATIONS Results to date indicate that corn responds to applied P and K at soil test levels currently used to make recommendations to apply P and K. Results to date do not show a response to applied P and/or K at soil test levels too high to warrant a recommendation under the current guidelines. LITERATURECITED Muir, J.H., W.E. Sabbe, H.J. Mascagni, Jr., and P.W. Parker. 1992. Nitrogen rates for corn on Arkansas Delta soils. University of Arkansas Agricultural Experiment Station Bulletin 932. ACKNOWLEDGMENT Support for this research was provided by the Arkansas Fertilizer Tonnage Fee.
Table 1. Corn grain yield and soil test K levels as affected by applied K on soils with various initial soil test K levels. Arkansas State University, Jonesboro, Arkansas. Soil test K Soil K
K Rate
Initialz
Fall 97
Yield
Fall 98
Fall 99
97
98
99
00
------------------------------ lb/acre ----------------------------
------------ bu/acre ----------
0 45 90 180
111 106 108 109
72 99 107 144
113 130 139 189
125 182 199 277
154 158 169 168
125 128 151 150
136 146 174 156
179 184 198 209
Moderately Low 0 45 90 180
135 138 133 138
95 106 109 158
126 173 157 228
158 188 189 291
169 159 150 182
118 121 138 131
146 140 160 161
191 189 203 211
Low
Medium
0 45 90 180
157 165 162 159
104 113 139 187
147 158 173 238
165 210 242 294
176 184 181 164
138 133 150 147
152 155 161 169
186 195 196 197
High
0 45 90 180
226 195 204 245
121 128 160 212
151 164 214 280
200 213 280 333
177 183 183 179
147 127 143 135
160 167 163 150
187 192 181 180
11
25
21
25
16
9
12
15
LSD(0.05) z
Spring 1997.
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Arkansas Soil Fertility Studies 2000
Table 2. Corn grain yield and soil test P levels as affected by applied P on soils with various initial soil test P levels. Arkansas State University, Jonesboro, Arkansas. Soil test P Soil P
P Rate
InitialZ
Fall 97
Yield Fall 98
----------------------------- lb/acre ----------------------------
97
98
99
----------- bu/acre -------
Low
0 35 70 140
21 22 21 23
19 25 27 53
17 23 22 27
159 152 165 173
133 136 142 145
142 152 164 153
Medium
0 35 70 140
31 29 27 28 5
24 28 37 62 12
20 22 23 30 3
168 173 182 174 16
134 134 138 138 9
148 151 164 165 12
LSD(0.05) z
Spring 1997.
Table 3. Corn grain yield and soil test P levels as affected by applied P on soils with various soil test P levels, 2000. Arkansas State University, Jonesboro, Arkansas. Applied P 0 35 70 140 LSD(0.05) z
Soil test Pz
Yield
lb/acre
bu/acre
21 26 32 52 5
185 191 196 198 15
Fall 1999.
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CORN RESPONSE TO NITROGEN AND PHOSPHORUS AS STARTER FERTILIZER J.H. Muir and J.A. Hedge RESEARCH PROBLEM The early spring planting dates required for optimum corn production in Arkansas often expose corn seedlings to lower than optimum soil temperatures. The low soil temperatures may result in slow root growth and phosphorus (P) deficiency even though soil test levels of available P are considered adequate. BACKGROUND INFORMATION Placing small amounts of starter fertilizer, usually nitrogen (N) and/or P, with or near the seed has increased early-season corn plant height and grain yield and decreased the number of days to silking of corn in northeast Louisiana (Mascagni and Boquet, 1996). RESEARCH DESCRIPTION A study was initiated on the Arkansas State University campus in the spring of 1999 to determine the response of corn to starter N and P fertilizer. Nitrogen at 5 lb/acre and P at 8 lb/acre alone and together were applied with the seed in 1999. Nitrogen at 15.5 lb/acre and P at 25 lb/acre alone and together were applied approximately 2 inches to the side and 2 inches below the seed in 2000. RESULTS There was some indication that stands were reduced with some treatments in 1999 when fertilizer was placed with the seed (Table 1), even though rates of N and P were at levels that literature references indicated to be safe. Although there were no statistically significant yield differences in 1999, there was a trend for a yield increase with starter fertilizer for hybrids P3335 and P3245. There was a significant response to starter P alone in 2000 (Table 2). There was a trend for the N and NP treatments to yield more than the control. This response to starter fertilizer was the same for all varieties. PRACTICALAPPLICATIONS The first two years’ data indicate that starter fertilizer can, at times, increase the yield of corn and may be a worthwhile practice.
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LITERATURECITED Mascagni, H.J. Jr., and D.J. Boquet. 1996. Starter fertilizer and planting date effects on corn rotated with cotton. Agron. J. 88:975-982. ACKNOWLEDGMENT Support for this research was provided by the Arkansas Corn and Grain Sorghum Promotion Board.
Table 1. Influence of starter fertilizer, nitrogen (N) and phosphorus (P), on corn yield. 1999. Arkansas State University, Jonesboro, Arkansas. Hybrid
Starter fertilizer
P 3335 P 3335 P 3245 P 3335 P 3245 NK 7590 P 3335 NK 7590 P 3245 NK 454 NK 7590 NK 454 NK 454 P 3245 NK 7590 NK 454 LSD(0.05)
N NP P P N NP Control Control Control Control P N NP NP N P
Plant population
Yield
1000/acre
bu/acre
15488 17061 16698 16998 15730 16577 15730 19844 14399 16214 14762 15125 17424 12705 15609 13310 3598
118 113 111 107 106 104 103 103 103 102 99 99 98 95 94 86 23
Table 2. Influence of starter fertilizer, nitrogen (N) and phosphorus (P), on corn yield. 2000. Arkansas State University, Jonesboro, Arkansas. Starter Fertilizer
Yield bu/acre
P N NP Control LSD(0.05)
146.6 127.4 127.0 113.7 17.7
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PHOSPHORUS FERTILIZER RATE AND APPLICATION TIME EFFECT ON SOYBEAN YIELD N.A. Slaton, R.E. DeLong, S. Ntamatungiro, S.D. Clark, and D.L. Boothe RESEARCH PROBLEM In eastern Arkansas, soybean [Glycine max (Merr) L.] frequently follows rice (Oryza sativa L.) in the crop rotation sequence. Soil samples collected annually in a rice-soybean rotation show that soil test phosphorus (P) (Mehlich-III P) declines after rice and gradually increases until rice is grown in the rotation again (Slaton et al., 2000). This decline is not entirely a result of P removal by harvested rice but is due to changes in chemical forms of soil P. Soil test information and the resulting fertilizer recommendations can be significantly impacted by the crop grown before soil samples are taken. Our knowledge of P fertilization practices used in crop rotations that include rice is limited. The literature shows the availability of P is generally reduced to crops immediately following rice in rotation and that crops following rice may suffer from P deficiency if adequate P fertilizer is not applied. The objective of our study was to evaluate soybean response to P fertilizer rate when applied at different times during a rice-soybean crop rotation. RESEARCH DESCRIPTION A 1:1 soybean-rice rotation was established in 1998 at the Pine Tree Branch Experiment Station (PTBES) and the Rice Research Extension Center (RREC). Selected soil information is presented in Table 1. A detailed description of this research is provided by Slaton et al. (2000). At each location, soybean (‘Hutcheson’) was grown in 1998, rice in 1999, and soybean again in 2000. Phosphorus fertilizer was applied at rates from 0 to 120 lb P2O5/acre at different times in the rotation including i) annually, ii) only to rice, and iii) only to soybean. In 2000, whole plants (4 plants cut at soil surface) and most recently mature trifoliate leaves were collected at the R2 growth stage. Grain yield was measured at maturity, and yields were adjusted to 13% moisture. RESULTS Soil test P was significantly affected by the time and rate of P application at both locations (Tables 2 and 3). Compared to the untreated control, soil test P increased as P application rate increased. Soil test P was always highest when applied to both rice and soybean in the rotation. Application of P fertilizer only to rice or soybean increased soil test P, but not to the same extent as annual applications. A consistent yield response to P fertilizer application was not found among application rates or time of application at either the RREC or PTBES (Tables 4 and 5).
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Tissue P concentration tended to increase with increasing P rate at the RREC but showed no response to P rate at the PTBES (Table 6). Tissue concentrations tended to be highest when P was applied annually, but failed to show a consistent response across locations (Table 7). Tissue P concentration of the trifoliate leaves was above 0.30%, which is considered sufficient. PRACTICALAPPLICATIONS Soil test results show that annual P fertilizer application rates in excess of crop removal are required to maintain soil test P on silt loam soils cropped to both rice and soybean. Growers intent on increasing soil test P values will apply excessive rates of P fertilizer, increase production costs, and obtain little or no yield benefit. Data suggest that the Mehlich-III extractant may not adequately predict soybean response to P following rice in the rotation. LITERATURECITED Slaton, N.A., C.E. Wilson, Jr., S. Ntamatungiro, R.J. Norman, and D.L. Boothe. 2000. Effects of previous crop and phosphorus fertilization rate on rice. In: R.J. Norman and C.A. Beyrouty (eds.). B.R. Wells Rice Research Series 1999. University of Arkansas Agricultural Experiment Station Research Series 476:294-303. ACKNOWLEDGMENT Funding for this project was provided by the Rice Checkoff Program.
Table 1. Selected soil properties from the Pine Tree Branch Experiment Station (PTBES) and the Rice Research and Extension Center (RREC) locations during 2000. Location
Soil series
pH
K
Ca
Mg
S
Fe
Mn
Zn
Cu
----------------- lb/acre (Mehlich-III Extractant) ---------------PTBES RREC
Calloway silt loam DeWitt silt loam
7.5 5.9
201 250
3569 1787
781 240
66 24
502 560
119 169
7.9 2.8
2.0 1.5
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Table 2. Influence of phosphorus (P) fertilizer application rate, averaged across time of application, on Mehlich-III soil test P in 2000 at the Pine Tree Branch Experiment Station (PTBES) and the Rice Research and Extension Center (RREC) locations during 2000. PTBESz
RRECz
P Fertilizer Application Rate
Initial value in May 1998
lb P2O5/acre
--------------------------------- lb Mehlich-III P/acre ---------------------------------
0 20 40 80 120
50.8 51.4 51.4 51.7 52.2
LSD(0.05) P-value C.V., % z
February 2000 32.0 36.3 41.4 50.9 55.8
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