Effects of cow urine on growth of pasture and uptake of nutrients

New Zealand Journal of Agricultural Research ISSN: 0028-8233 (Print) 1175-8775 (Online) Journal homepage: http://www.tandfonline.com/loi/tnza20 Effe...
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New Zealand Journal of Agricultural Research

ISSN: 0028-8233 (Print) 1175-8775 (Online) Journal homepage: http://www.tandfonline.com/loi/tnza20

Effects of cow urine on growth of pasture and uptake of nutrients G. During & K. J. McNaught To cite this article: G. During & K. J. McNaught (1961) Effects of cow urine on growth of pasture and uptake of nutrients, New Zealand Journal of Agricultural Research, 4:5-6, 591-605, DOI: 10.1080/00288233.1961.10431617 To link to this article: http://dx.doi.org/10.1080/00288233.1961.10431617

Published online: 15 Feb 2012.

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Date: 16 January 2017, At: 05:43

591

EFFECTS OF COW URINE ON GROWTH OF PASTURE AND UPTAKE OF NUTRIENTS By C. DURING

AND

K.

J.

McNAUGHT

Farm Advisory Division, Department of Agriculture, Wellington

(Received 16 June 1961) ABSTRACT A field trial was conducted on permanent pasture on !vlarton loam with cow urine and a nearly equivalent rate of KCI. Its objects were: (1) To determine the' apparent recovery of applied. nitrogen and potassium. (2) To evaluate the effect of these treatments on the magnesium and calcium in pasture and soil. The apparent recovery of applied nitrogen in the herbage was only 10 per cent of that applied in urine. The apparent recovery of potassium in the herbage was 20-23 per cent of that applied in urine or KCI. No difference was observed in the action of potassium whether applied as urine or as KCI. The effect of urine nitrogen on yields and on N concentration in the pasture lasted only about two months. The effect of applied potassium on yields and K concentration in the pasture was significant for two years. Urine and KCI depressed the concentration but not the uptake of Mg and P in the herbage and slightly lowered the level of exchangeable magnesium in the soil. Considerable losses of Nand K and some losses of Mg and Ca are likely to occur under urine spots.

INTRODUCTION Animal excreta are an essential part of the fertility cycle in grazed pastures, as was demonstrated experimentally by Sears (1953). Using sheep, this investigator found that the return of dung and urine to grazed pastures greatly increased yield, especially by the stimulation of growth of perennial ryegrass, and raised the concentration of potassium, phosphorus, and nitrogen in the herbage. On the other hand, plant nutrients returned in dung and urine are concentrated on relatively small areas. Following the application of urine, Thompson and Coup (1943) found a gradual but appreciable rise in soil nitrate levels. On leaching, this nitrate is expected to take with it an equivalent amount of cations. Thus N.Z. ]. agric. Res. 4: 591-605

592

EFFECTS OF COW URINE ON PASTURE

in a urine spot the association of nitrate anct water-soluble potassic salts might be expected to expose urine potassium, and possibly other ions, such as magnesium and calcium, to a particularly high risk of leaching. The high concentration of potassium alone is likely to lead to accelerated losses of exchangeable magnesium, as shown by Hogg (1960). Saunders and Metson (1959) measured leaching losses of potassium applied as chloride and in the form of urine, in a pot trial. Although conditions in this experiment were somewhat artificial, evidence obtained on accelerated leaching of potassium, calcium, and magnesium pointed to the possibility that similar effects under urine spots or after top-dressing' with high rates of KCI might occur in the field. In the field, however, it is impossible to determine leaching losses without a battery of large Iysimeters. For this reason the experiment described below limited itself to a recording of the quantities of nitrogen and potassium applied in urine and to measuring quantitatively the amounts of these elements and of calcium, magnesium, and phosphorus which were taken up by pasture on treated and untreated plots. Measurements of pasture uptake of these elements were carried out until yield, nutrient concentration, and nutrient uptake were equal on treated and untreated plots.

EXPERIMENT.\T, Techniqu('

l'relinary trials were carried out by the senior author in 1956 to determine the likely size of urine spots under selected conditions. vVater with precipitated chalk added as a marker was poured from a height of 2 ft 6 in.-3 ft on to slightly sloping to level moist ground covered with short dense pasture. The nozzle of the watering can was adjusted to release 2 litres in 10 seconds, or H Iitres in 7.5 seconds, following the cia ta published hy Goodall (1951). On a calm day on nearly flat ground the average area covered was very similar to that found by Petersen rt at. (1956)-about 400 sq. in.hut less than the 650 sq. in. estimated by Doak (1952). In a strong breeze dispersion of the main stream and much splash resulted in increasing the area to an average of 780 sq. in. On a calm day but on sloping ground the area was increased greatly to over 1,000 sq. ill. in individual spots.

Soil Tw() experiments were carried out on Marton loam at Marton. This soil type is classified as a Y c1low Grey Earth Transitional to a Yellow Brown Earth (N.Z. Soil Bureau 1954). It is derived from sandy mudstone. There is a ccmpact subsoil which impedes drainage. In the experiments reported drainage was satisfactory owing to mole ploughing. The annual average rainfall is about 40 in.

C. DURING

&

K. J. McNAUGHT

593

Experim ent 1 (Technique trial) The first experiment was a technique trial. It was designed: 1. To measure the influence of urine on the concentration of K in the herbage growing just outside the area wetted by unne. 2. To estimate the variability likely to occur in the concentration of K in the herbage on very small plots. On 13 September 19562,000 ml of urine was applied to each of eight plots measuring 14 in. X 30 in. (420 sq. in) (165 Ib Nand 230 Ib K per acre). The pasture consisted almost entirely of white clover, red clover, and perennia I ryegrass. The first sample of herbage was hand cut 7 weeks after the urine was applied; the last sample was taken 7 months later. Some of the results obtained in the first and last cuts are presented in Tables 1 and 2. TABLE 1. TECHNIQUE TRIAL, 1ST CCT. % K in herbage dry matter-31 October 19S() Position

1Iean of 8 plots

Lowest value

Highest value

3.51

2.65

4.00

Just inside plots Centre of ]llots

3.61

3.0H

3.96

1- 3 in. outside

3.29

2.40

4.37

3- 5 in. outside

3.05

2.30

3.78

10-13 in. outsicle

3.02

2.23

3.78

In the interval between cuts the plots were mown and the herbage discarded. Heavy rainfall in May.led to flooding of four of the eight plots. These had to be eliminated. TABLE 2. TECHNIQUE TRIAL, LAST CUT. % K in, herbage dry matter-28 ::\fay 1957 Position

I Mean of 4 plots

Lowest yalue

I Grasses i Cloyers Grasses Cloyers

I I

Highest value . Grasses I Clovers

Inside plots

2.92 I

1.75

2.18

1.42

0-- 3 in. outside

2.69

1.64

2.29

1.30

3.67

2.07

3- 6 in. outside

2.54

1.65

2.18

1.14

2.91

2.09

6- 9 in. outside

2.45

1.70

2.19

1.53

2.97

2.09

9-12 in. outside

2.58

1.59

2.18

1.43

3.08

1.84

I

4.24

I

2.40

594

EFFECTS OF COW URINE ON PASTURE

The results indicate that very little or no transfer of potassium had occurred 3 in. beyond the border of the plots. On the other hand, there appeared to be very high variability in potassium concentration. For this reason the main trial was replicated 10 times and a buffer strip of 5 in. was decided on as being adequate.

Experiment 2 (Main trial) In the second and main trial the following treatments were put down, replicated 10 times, on 20 November 1957: 1. No treatment. Control. 2. Urine at 2,000 ml to 420 sq. in. 3. KCl at approximately urine equivalent to 420 sq. in. (A further 5 treatments put clown in May 1958 had to be discarded because of the suspected spread of treatments beyond the plots following a very heavy downpour of rain.) Each individual plot consisted of a "core area," measuring 14 in. X 30 in. (420 sq. in.), surrounded by a 5 in. wide buffer strip. Before applying the urine a rectangle made from 8 in. wide galvanised iron and measuring 14 in. X 30 in. was placed firmly to outline each core area. KCl was applied dry, and adhering crystals were brushed off the leaves. Urine was applied with watering cans, taking care to avoid any flow of urine beyond the boundary of the core area. The urine was collected during milking at Flock House, a nearby farm. Rates of application of nitrogen and potassium, in lb/acre, were as follows:KCl

Urine

N

K

K

329

593

518

Herbage was cut, when 3 in.-5 in. high, on the core area and on the 5 in. wide surround, or on an area of 24 in. X 40 in. A reel mower with 24 in. wide blades was used. Permanent pegs were placed to guide the mower to cut each plot area within -t- 1 in. accuracy. Thus the width of the cut buffer strip surrounding the core area varied from 4 in.-6 in., and the plot size cut from 24 in. X 38 in. to 24 in. X 42 in. (Note that treatments were applied to only 14 in. X 30 in.). The herbage from each plot was weighed, dried, and stored. For chemical analysis separate cuts were analysed at intervals to

C. DURING

K.

&

J.

595

McNAUGHT

determine the potassium status, while the intermediate cuts were bulked. Dissections of pasture species were not carried out. For soil analyses five 1 in. diameter cores per plot were taken. RESULTS

(Main trial) The main trial began satisfactorily; the November 1957 applications did not burn the pasture, and no urine was observed to run outside the core area. Good growth responses to urine, particularly by grass, became apparent within a few weeks; but by the beginning of February, 80 days after application, all plots were dominated by white clover. As judged by eye, clover vigour was best on the KCl-treated plots, followed by those which had received urine. Typical K deficiency symptoms appeared on isolated clover plants on untreated plots. By May 1958 clovers on the "control" plots were small and stunted. Yields and chemical analyses of herbage quoted refer to the whole area of each plot, measuring 960 sq. in., but urine and KCI were applied only to the 420 sq. in. core of each plot. The area affected by treatments was probably larger than 420 sq. in., and almost certainly smaller than 960 sq. in. The differences in yield and nutrient concentration quoted are therefore smaller than the actual differences on the core area within plots. The calculations of total uptake of nutrients, however, are accurate unless the peripheral effect of treatments extend more than 4-5 in. beyond the boundaries of the treated core.

Yields of pasture herbage Table 3 presents a summary of herbage yields in Ib dry matter per acre, measured on a 960 sq. in. plot basis. In this and the tables following significant differences are determined by Duncan's Test (Duncan 1955). TABLE 3.

SUMMARY OF PASTURE HERBAGE YIELDS (lb dry matter/acre*) Period

Treatments

20.11.5714.1.58

I

14.1.5819.11.58

I

19.11.5823.11.59

-'--_._..-

I

I

23.11.5912.7.60

Control

1,780 c B

6,520 b B

7,390 b A

2,630 a

Urine

2,850 a A

7,210 a A

2,580 a

KCl

1,980 b B

i

7,780 ab A

7,110 a A

7,860 a A

2,740 a

I

5.3%

5.6%

10.7%

Coeff. of variation

8.7%

I

I

* Treatments which do not have a common capital letter differ significantly at the 1 per cent level; treatments which do not have a common small letter differ significantly at the 5 per cent level; treatments which have a small letter in common do not differ significantly.

596

EFFECTS OF COW URINE O::.J PASTURE

The stimulating effect on yields of urine compared with that of KCl lasted only until the cut of 14.1.58, that is, for about 50 days. Later cuts for which individual yield data are available, although not presented here, show no differences in yield beween the urine and KCI plots. The relatively small effect of urine nitrogen on yields is no doubt partly due to the time it was applied. The date of application of urine in this trial coincides with a period of the year in which growth responses of grass-clover pasture to nitrogen are usually very small. In addition, November, December, and January were wet months, with a total rainfall of 17.4 in. The possibility of rapid leaching of nitrogen therefore cannot be excluded. Growth responses to applied potassium were statistically significant until the end of the second year.

Concentration of nutrients in the pasture herbaye A true measure of treatment effects on the concentration of nutrients in the pasture herbage on the urine-treated area is not possible because of the difference between the area treated (420 sq. in.) and the area cut (960 sq. in.). Also as all herbage of each cut was needed to determine potassium recovery, it was considered impracticable to attempt dissection into grasses and clovers. This limits the interpretation of the data on nutrient concentration in the herbage, since clovers usually have higher concentrations of magnesium, and, especially, calcium, than grasses, and lower levels of potassium. Except for the initi:l1 boost of grass growth on the urinetreated plots the treated core areas appeared to contain a greater proportion of white clover than did control. The percentage concentration of nutrients in the herbage is summarised in Table 4. At the first cut one month after the trial began, the potassium concentration in the herbage from the untreated plots was near the critical level at which potassium deficiency could be expected in mixed pasture (McNaught 1958). It is most likely that in the treated core area potassium concentration of the herbage was adequate one year after the trial was laid down but that it fell rapidlv to deficiency levels in the first half of the second year of the trial. Under the conditions of this trial, therefore, the application of potassium at the rate of about 9 cwt of muriate of potash per acre protected pasture from which herbage was removed against potassium deficiency for a period of not much longer than one year. There is little doubt that 18 months after the trial began all treatments were very potassium-deficient and that after two years the effect of treatments on potassium concentrations was negligible.

I

I

1. Contrd 2. Urine 5. KCI Coeff. of variation (%)

..

II

'I

6.1

0.34 b AB

0.37 a A 0.33 b B

'

3.5

0.32 a A 0.28 b 13 0.28 b 13

6.6

1.02 a A 0.96 b A 0.97 b A 4.2

1.32aA 1.14 b 13 1.27 a A

5.6

1.l2aA O.W c C 1.04 b B

7.2

4.7

1.02 a 1.02 a 1.02 a

5.0

0.25 b B 0.26 b B

0.28 a A

0.42 b 0.42 b

I

0.42 a 0.42 a

I, 3 . 8

3.7

II 0.44 a

I

I

I

'I

Cuts 9.6.5923.11.59

4.3

0.35 a A 0.32 b B 0.32 b B

6.5

0.39 b 13

0.43 a A

0.39 b B

I

7.0

0.28 a

3.8

0.44 a B 0.41 b B 0.42 b AB

3.6

I 0.29 a I 0.28 a

I

I 3.82 a 3.83 a

I 3.75 a

9.6

0.93 a 0.92 a 0.93 a

5.1 7.0

0.95 a 0.97 a 0.96 a

--,--------,----

I

I[

3.3

4.76 a 4.87 a 4.91 a

14.1

1.12 b 13 I: 1.32 b A l.27 ab A13! 1.42 ab A 1.38 a A 1.48 a A

Cut 30.4.59

1.12bA 1.20 a A 1.15 ab A

6.2

---,

0.36 a A 0.34 ab A 0.33 b A

56

0.41 a A 0.38 b B 0.37 b 13

3.4

4.30 b A 4.46 a A 4.50 a A

11.8

1.20 b B 1.45 a A 1.48 a A

Cuts 6.1.592.4.59

I

7.7

I 4.21 a 4.32 a 4.23 a

1.64 b 13 2.04 a A 2.15 a A

I

Cuts 7.7.5819.11.58

I 0.43 a

2.4

5.18 a 5.21 a 5.18 a

9.4

2.33 a A

- - - - - ,- - _ . _ - - - - - - -

5.4

0.28 a A 0.25 b B 0.25 b B

5.3

6.5

0.51 b 13 0.52 b AB

0.55 a A

--- -------5. % Ca

4. % Mg 1. Control 2. Urine 5. KCi Coeff. of variation (%)

3. % p 1. Control 2. Urine 5. KCI Coeff. of variation (%)

2.9

0.45 a 0.43 a 0.44 a

5.1

variation (%)

Coeff. of

5.19 a 5.05 a 5.19 a

Cut 7.5.58

I 1.50 b 13 I 2.37 a A

8.5;

1.82 b B 2,79 a A 2.71 a A

Cuts 14.1.581.4.58

CONCENTRATION OF NUTRIENTS IN THE DRY HERBAGE

I

3.63 b B 3.91 a A 3.68 b AB

12.1

2.10 c B 3.35 a A 2.92 b A

Cut 23.12.57

1. Control 2. Urine 5. KCI

2. % N

1. % K 1. Control 2. Urine 5. KCI CoefI. of variation (%)

Treatment

TABLE 4.

I

I I

I

I

7.2

---

7.6

1.03 a 1.08 a 1.07 a

-

0.33 a 0.34 a 0.33 a

6.4

0.49 a A 0.43 b B 0.44 b 13

4.0

4.21 b A 4..39 a A 4.37 ab A

5.4

1.34 a 1.30 a 1.34 a

Cut 14.12.59 I'

6.8

GU8 a A 0.36 ab A 0.35 b A

-

3.83 a 3.88 a 3.83 a

7.1

1.19 a 1.22 a 1.23 a

I I

I

1.01 a 0.99 a 0.99 a

----.

8.0

0.37 a I 0.36 a I 0.37 a

,

I

I

'[

I

Cuts 23.3.6012.7.60

(Jl

\0 '-l

>-l

~

o

e>-

Z

n

s;::

'-

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