THE EFFECT OF URINE AND ITS COMPONENTS ON THE BOTANICAL COMPOSITION AND PRODUCTION OF A GRASS/CLOVER SWARD

A study was made of the effect of sheep urine and some of its components on herbage production. The return of urine to the sward increased production from the grass species; the clover content of the sward was reduced.
The application of nitrogen or potassium fertilizer equivalent to the normal return of nitrogen and potassium in urine increased production, but not as much as urine. The return of nitrogen and potassium fertilizer together increased production and altered botanical composition in much the same way as did urine.
On a grass-dominant urine-treated sward the application of nitrogen fertilizer increased the "efficiency" of urine.
The effect of urine on a grass/clover sward was almost entirely due to its nitrogen and potassium content. The water and indole acetic acid content of urine had no effect on pasture production or composition.     

A COMPARISON OF THE REACTION OF DIFFERENT GRASS SPECIES TO FERTILIZER NITROGEN AND TO GROWTH IN ASSOCIATION WITH WHITE CLOVER

Seven species or varieties of grass, and a mixture of 3 of them, were sown in pure swards and treated with 4 levels of nitrogenous fertilizer (0,17·5, 35 and 70lb N per acre per cut). Each species, and the mixture, was also sown with white clover. The experiment was cut 4 or 5 times per year. The effect of fertilizer on the yield of each grass was compared with the effect of clover on the yield of the grass/clover swards. Mean annual yields showed an approximately linear response to N; there was a small but significant fall in response to the highest level of N. Response among the species ranged from 20 to 30 Ib of dry matter per Ib N applied for the intermediate level of fertilizer and from 14 to 23 Ib for the final increment of fertilizer.
S37 cocksfoot, S48 timothy, S24 ryegrass, and a mixture of these grasses, were high yielding and responded well to fertilizer N; Irish ryegrass and Agrostis tenuis were less productive and gave poorer responses to N. S215 meadow fescue and S23 ryegrass were intermediate in yield and response.
There were no significant differences between the annual yields of the 8 grass/clover mixtures; the yields of the grass and clover components of each mixture were inversely related. The effect of clover on the yield of the grass/clover mixtures was estimated to be equivalent to the effect of an annual application of 205 lb N per acre to Agrostis tenuis and 120 lb N to S48 timothy. The fluctuations in annual yields were greater with grass/ clover mixtures than with grass swards receiving N.
The yields of grasses when sown with clover were in similar order to their yields when sown pure; but whereas the latter tended to fall from year to year, the yields of the grass components of mixtures (except Irish ryegrass) did not.     

THE INFLUENCE ON THE FOLLOWING ARABLE CROP OF SHEEP EXCRETA AND FERTILIZER TREATMENTS APPLIED TO A LEY

The differences in soil fertility in a ley as a result of treatments applied for four years in a sheep-grazing trial were measured by growing crops of wheat and kale. The pasture treatments had been: control, dung, urine and dung plus urine, each combined with four levels of fertilizer nitrogen.
Yields of winter wheat harvested in 1956 ranged from 27.1 to 38.6 cwt. per acre. Plots to which faeces had been allowed to return during the pasture phase outyielded (p <0.001) those from which it was withheld. Urine was relatively ineffective except in combination with nitrogen. In the absence of animal returns, nitrogenous fertilizer depressed grain and straw yields. A top-dressing of K applied to the wheat in spring as a sub-treatment had no significant effect. The percentages of N and K in the grain were unaffected by the former pasture treatments, or by the K top-dressing.
A subsidiary small-plot experiment in which the above pasture treatments had been combined with P and K, each at two levels, was cropped with marrow-stem kale. In general, N applied to the pasture increased kale yields except where dung and urine had been withheld. Neither P nor K had a significant effect, except when combined. The leaf/stem ratio of the kale was reduced by applied N and by P (both p <0.05).
The pasture/arable-crop relationship is considered.     

THE GRAZING ANIMAL AND SWARD PRODUCTIVITY

A trial designed to show the effects of animal excreta on sward productivity is described.
It was estimated that the grazing sheep returns in a season nutrients capable of immediate uptake by the plant equivalent to 5–6 cwt. nitro-chalk and 2–21/2 cwt. 60% muriate of potash per acre.
A large part of sward yield depended on animal return. Clover depression from the effects of animal excreta and, under mowing treatment, from the effects of fertilizer nitrogen, did not result in marked loss of transferred clover nitrogen. There appeared to be a gain in clover soil-nitrogen from a reduction of the clover stand.
A comparison is made between the restilts obtained from sheep excreta on the sward with those obtained from mowing treatment.
The interaction between animal or fertilizer nitrogen and the clover plant is discussed.     

THE EFFECT OF WHITE CLOVER AND NITROGENOUS FERTILIZER ON THE PRODUCTION OF A SWARD

Three-year leys of cocksfoot/white clover and cocksfoot alone were dressed with 0, 35, 105 and 210 lb. N per acre every year to provide information on the effect of clover and N on annual production.
White clover contributed 40% of the dry-matter yield but its presence was responsible for 77% of this yield where no N was used: it was responsible for less than 8%, and contributed 5%, where 210 lb. N per acre was applied annually, lt was estimated that grass alone receiving 160 lb. N per acre would yield as much dry matter as a mixed sward receiving none.
Clover had the indirect effect of raising yield of nitrogen in the companion grass by 60 lb. per acre per year. A maximum of l06 lb. was recorded in 1958.
The response of the tnixed sward averaged 10 lb. of dry matter per lb. N. Prevailing economic circumstances will determine if this level is satisfactory in practice.
The recovery of N by grass alone varied from 54% at the lowest level of N to 80% at the highest. On mixed swards apparent recovery was negative or low: N was to a large extent only replacing the effect of clover which was suppressed by its use.
Factors influencing response and the difference between that obtained under experimental and practical conditions are discussed.
The use of N to produce out-of-season grass may give good response, but may cause a reduction in clover contribution.     

THE LOCAL INFLUENCE OF CATTLE DUNG AND URINE UPON THE YIELD AND BOTANICAL COMPOSITION OF PERMANENT PASTURE

A study was made of the local effects on yield and botanical composition of the herbage of cattle dung and urine applied to permanent pasture as simulated defaecations and urinations.
A single application of urine had a negligible effect upon botanical composition. In the 2-ft.-diameter circle around dung patches there was an increase in cocksfoot, creeping bent, red fescue and white clover, and a decrease in herbs.
Urine patches were neglected by grazing stock for short periods only. Herbage around dung patches was neglected for a period varying from 13–18 months. The effect of this neglect was to restrict the spread of white clover around dung patches in comparison with similar plots kept short by cutting.
Yield response to urine in the area of deposition lasted for two cuts following application, response to dung for four cuts. An increase in crude-protein content of the herbage was recorded only in samples taken one month after application of dung or urine, and not later.
Increases in crude-protein yield following spring applications of dung or urine were greater than those following autumn applications. The inferiority of autumn applications may be attributed to winter leaching of nitrogen.     

THE EFFECT OF DUNG AND URINE AND ITS INTERACTIONS WITH APPLIED NITROGEN, PHOSPHORUS AND POTASSIUM ON THE CHEMICAL COMPOSITION OF PASTURE

The importance of the grass/clover balance of a pasture in determining the effects of manurial returns and fertiliser applications on the chemical composition of the sward is shown.
The response to applied nitrogen was very dependent on the presence or absence of the animal excrements. For example, the N recovery from an application of 18 cwt. per acre of nitro-chalk was only 2% in the absence but 68% in the presence of the grazing animal.
Urine caused a marked increase in the N and K content and the yield of pasture, particularly when returned in quantity to a high-producing grass-dominant sward, and at the same time tended to depress the Ca, P and Mg content. Urine K was superior to fertiliser K, per pound of K returned or applied, in raising the K content of the pasture.
By comparison, dung had little direct effect on chemical content; even when returned in large amounts it affected the Ca and K content of the pasture to a relatively small extent. The P returned in the dung had little effect on the P content of the pasture and was inferior to superphosphate in this respect.
Together, as in normal grazing, dung and urine tended to counter or enhance their individual effects.
There was a positive correlation between the Mg and P content of the pasture and a negative correlation between Mg and K. Brief mention is made of the possible importance of the nutrient balance in pasture as a factor in animal health.     

THE EFFECT OF WHITE CLOVER, FERTILIZER NITROGEN AND SIMULATED ANIMAL RESIDUES ON YIELD OF GRASSLAND HERBAGE

An experiment is described which measures the effects of white clover, fertilizer nitrogen and simulated animal residues, alone and in all combinations, on total herbage production from a perennial ryegrass sward. Yields of oven-dry herbage and of nitrogen are quoted. Two cuts were taken in the seedling year and four to six in each of three full harvest years.
Yield response to fertilizer nitrogen was similar to that in some other experiments in the U.K., while the beneficial effect of clover on yield was rather greater.
Negative nitrogen ± clover and positive nitrogen ± animal residues interactions were found throughout the yield data. There was a positive clover ± animal residues interaction in the first harvest year (dry-matter yield only), and a negative nitrogen ± clover ± animal residues interaction in the second harvest year.
The results are discussed in relation to other published work and to their application in practice.     

THE VIABILITY OVER A PERIOD OF FIFTEEN YEARS OF SEVERELY DRIED RYEGRASS SEED

Perennial ryegrass seed was dried at temperatures from 50°C to 120°C, the increases of 10°C being made regularly at intervals of 3 hours. The figures for germination capacity obtained immediately after treatment indicated that a lethal zone had been reached with final temperatures above 100°C and moisture contents reduced to 0.09 and 0.00 per cent.
It was shown that heat drying to as low as 0.66 per cent moisture at a final temperature of 100°C for 3 hours does not injure the germination capacity over a period of seven years, but after 15 years a greater loss in viability appears than in seed treated less severely. Germination energy figures (6-days' test) rather than germination capacity are a more reliable guide to optimum temperatures, duration of heating, and moisture content in the drying of seed for long-period storage.
The most favourable treatment in this series was found to be heating the seed gradually to a maximum temperature of 90°C for 3 hours with a reduction of moisture content to 1.62 per cent. Seed thus treated showed 81 per cent germination after 15 years; for the last eight years the bottles were stored in a cold room, after replacing the air in them with nitrogen.     

A STUDY OF THE INFLUENCE OF NITROGEN ON THE ROOT WEIGHT AND NODULATION OF WHITE CLOVER IN A MIXED SWARD

Experiments are described in which a study was made of the top growth, root weight, nodule number, and type of nodules of white clover growing in a grass sward in the field. Soil cores were taken and the clover root-system examined after removal of soil by washing.
The most important factor governing the total number of nodules and the number of large (2 mm. or more in length) nodules under the sward was the amount of clover root-material present.
Nitrogenous fertilisers and the return of dung and urine by grazing sheep reduced the amount of clover root-weight and consequently the number of nodules found under the pasture. 36 1b. of nitrogen applied in the early spring of 1956 had a beneficial effect on both clover top-growth and nodulation. 80–100 1b. of nitrogen per acre had no effect on the number of nodules per gram of root. However, the application of 200 1b. of nitrogen per acre caused a significant decrease in the number of large nodules per gram of root.
The numbers of large nodules present reached a midsummer peak where nitrogen was not applied.
During the autumn many nodules showed part green and part pink colouration or were completely green or brown, an indication of a decline in nitrogen-fixing ability. Decaying nodules increased considerably in number when the legume was being suppressed by nitrogen application and top growth was poor. The practical application of these results is discussed and methods of maximising the benefit from clover and fertiliser nitrogen are suggested.     

SOME EFFECTS ON THE YIELDS OF RYEGRASS STRAINS OF VARYING THE GROWING TECHNIQUE AND THE CONDITIONS OF MANAGEMENT

The effects are reported of varying the growing technique, and the conditions of management, on green and air-dry yields of herbage from five strains of ryegrass during 1952 and 1953. All strains were grown in three ways: as spaced plants, in drill-rows and in stands broadcast with white clover. There were two experiments, one managed for hay and aftermath, the other cut more frequently.
In both experiments the broadcast plots reached their peak of herbage production first; the spaced plants took longest. There were considerable differences in the seasonal distribution of yields from the different growing techniques during the first harvest year. In 1953, the differences were smaller but the secondary annual peak of herbage production observed in the broadcast plots was not detected in the spaced plants.
The total annual production per unit area was greatest from the broadcast, and least from spaced-plant plots. Yields on certain occasions, however, were greatest from spaced plants and least from broadcast areas.
The effects of varying the conditions of management were greatest on population samples sown broadcast and least on those growing as spaced plants, their reaction when grown in drills being intermediate.
Differences in plant population in the various growing techniques are discussed in relation to the above results.     

A COMPARISON OF THE HERBAGE YIELD OF ITALIAN RYEGRASS AND TALL FESCUE MIXTURES IN THE SECOND AND THIRD YEAR AFTER SOWING

The annual yield of tall fescue was higher than that of Italian ryegrass in the third year after sowing, but the total yield of herbage from grass plus clover swards was similar.
In both the second and third year after sowing, the yield of herbage in the spring grazing was higher when fescue was used as the sown grass. The method of establishment of both tall fescue and Italian ryegrass affected the total and seasonal yield in the second and third year after sowing, but the magnitude of these effects was not nearly as marked as it was earlier in the life of the leys. In the second year after sowing, swards of both Italian ryegrass and tall fescue had a higher yield of total herbage and of white clover, and a lower ingress of unsown species, when established without a cover crop and grazed frequently in the year of sowing.
The inclusion of red clover did not increase total yield of DM in the second and third year after sowing, and it slightly decreased the yield of the tall fescue mixture in the third year following sowing when N was applied. S170 tall fescue was readily grazed by sheep in spring and autumn.
The apparent recovery of applied N varied with the mixture sown, and the management given during establishment.     

THE PRODUCTION OF EARLY SPRING GRASS

The effects of autumn management and nitrogenous manuring on the production of early spring grass were studied from 1954 to 1957 on farms throughout England and Wales.
The most important management factor influencing spring yields was the application of spring nitrogen. In the early spring 6 to 10 lb. of dry matter were produced per lb. of nitrogen applied. Autumn nitrogen increased herbage yields in the auttimn by 8 to 17 lb. of dry matter per lb. of nitrogen applied.
Italian and perennial ryegrass responded well to autumn nitrogen but it was important to graze off the extra growth fairly quickly to prevent the sward becoming too open. The yield of ryegrass swards which received spring nitrogen were very much higher if they were grazed during the previous September and October than if they had been rested during those months.
In two years neither the autumn management nor alumni fertilizer appeared to influence the spring yields of cocksfoot, timothy or meadow fescue swards, in one year, however, when autumn growth was poor, autumn nitrogen and resting resulted in slightly better yields on these swards in the following spring.
It is suggested that resting swards during September and October to build up "reserves" is relatively unimportant in relation to the yields of grass in the following spring.     

THE EFFECT OF COMPANION GRASS AND SEED RATE ON THE PRODUCTIVITY OF A TALL-FESCUE SWARD

The effects of sowing from 10 to 50 lb/acre of tall-fescue seed on plant establishment and on the annual and seasonal distribution of DM yield of tall fescue and its companion grasses were measured through two growing seasons. Increasing the seed rate increased plant numbers per unit area and decreased per cent establishment. Adding Scots timothy as a companion grass depressed both plant number and per cent establishment. S37 cocksfoot and New Zealand perennial ryegrass reduced both still further. Total annual dry-matter production was relatively unaffected by varying either the seed rate or the companion grass. The contribution of tall fescue to total production was highest when sown alone and was successively reduced by timothy, perennial ryegrass and cocksfoot. When sown alone there were only slight differences in contribution of tall fescue due to seed rate. With any companion grass the contribution from tall fescue increased with increasing seed rate. Early growth was not reduced by modifying seed rate but was reduced by all the companion grasses. It is concluded that increasing the seed rate of tall fescue above 30 lb is not justified, that Scots timothy can be sown at 3 lb/acre with tall fescue without affecting total production or early growth of the mixture, with the advantages of control of unsown species and improved palatability of the herbage.     

STUDIES IN THE DIGESTIBILITY OF HERBAGE

This paper presents the results of 125 digestion trials with sheep fed herbage at different stages of growth from three clover-free pure grass swards. During 1958 and 1959, a study was made of the yield, leaf lamina, nitrogen, ash and digestible organic matter percentage ( D ) of first growths, of regrowths cut at monthly and two monthly intervals and of swards receiving various quantities of fertilizer nitrogen.
For first growths in the spring D remained almost constant until the ears started to protrude from the leaf sheaths and then fell rapidly at approximately 0·5 per cent per day. The D values for S 23 ryegrass were three weeks later than S 24 ryegrass, which correspond with later ear emergence of the latter. S 37 cocksfoot was always less digestible than S 24 ryegrass although both were at similar stages of growth. This difference in D also occurred in the regrowths. The D of monthly regrowths tended to fall with each successive cut, although in 1959 ryegrass values improved in the autumn.
Fertilizer nitrogen had little effect on D .
Despite the warmer spring and drier summer in 1959 and corresponding changes in production per acre there was little effect on D .     

THE RENOVATION OF DOWNLAND PERMANENT PASTURE II.

An experiment, A, involving dates and methods of application of 2,4-D (amine) as a preliminary treatment in the renovation of a poor downland permanent pasture, followed by surface cultivations and sowing of S.24 perennial ryegrass and S.100 white clover, was carried out at Hurley between 1953 and 1955.
In spite of initial differences in the establishment of S.24 and S.100, pre-treatment with herbicide had no effect upon the cover of sown and unsown perennial ryegrass and white clover two years later. At this date, perennial ryegrass contributed one-quarter and one-eighth, and white clover one-third and one-quarter, to the total cover of renovated and unrenovated plots respectively.
The increase in dry-matter yield resulting from renovation was approximately 10 per cent. This was considered small in relation to the estimated improvement in yield brought about by grazing management and manuring in the course of the trial.
In experiment B, plots receiving herbicide were given differential management and manurial treatments after spraying in an attempt to control the ingress of undesirable creeping grasses. The results indicated that this ingress could be checked by close grazing soon after spraying.     

THE EFFECT OF FERTILIZER NITROGEN AND FREQUENCY OF DEFOLIATION ON YIELD OF GRASSLAND HERBAGE

The effects of 4 levels of applied nitrogen, ranging from nil to a maximum of 417 lb N/ acre/annum, in all combinations with 3 frequencies of defoliation, ranging from 2 to a maximum of 10 cuts per annum, on herbage production from a perennial ryegrass/ timothy/meadow fescue/white clover sward were measured. These treatments were operative for 2J years, and in a subsequent year the residual effect of cutting frequency was tested. Dry-matter yields of total herbage and of the clover fraction are quoted, together with N yields of total herbage. Yield response to N was higher than in some other experiments in the U. K. Cutting frequency had a very large effect and, in general, the longer the interval between cuts, the higher was the dry-matter (though not the N) yield. There was a marked interaction between cutting frequency and level of N: at the high cutting frequency, dry-matter yield increased linearly with increasing level of N; at the medium frequency, response tended to fall off at the highest level of N; at the low frequency, yield declined with increasing level of N beyond 139 lb N per acre per anum.     

SOME EFFECTS OF GANGMOWING AND NITROGENOUS FERTILIZER ON A RYEGRASS/WHITE-CLOVER LEY

Gangmowing encouraged the spread of unsown grasses ( Poa spp.) in a ryegrass/white-clover ley, compared with grazing and no gangmowing. Herbage production from an ungrazed gangmown sward receiving a range of nitrogen dressings was higher than from grazed swards receiving little or no fertilizer nitrogen, but was almost identical at high rates of N application. The experiment was ploughed up in autumn 1955 and sown to wheat. The yields of wheat in 1956 were increased by previous nitrogen treatments up to the moderately high dressing but declined with the final increment.
Attention is drawn to the need for further experimental work on the practice of gangmowing.     

SOME EFFECTS OF GRAZING MANAGEMENT ON THE YIELD AND ITS COMPONENTS OF SOME PASTURE GRASSES

A study was made to determine the effects of grazing to a height of 1 in. when the swards reached heights of 3 and 9 in. on the dry matter production, LAI, tillering and rate of leaf production of new and old tillers in the spring–summer and autumn–winter seasons of 3 pasture species growing in association with white and red clovers. In both seasons the herbage yield under 9–1 management was higher than that under 3–1 and was significantly greater in the spring-summer season. Differences in DM production between cocksfoot, tall fescue and Ariki ryegrass failed to reach significance.
Light utilization under the 2 management systems was considered to be inefficient. In the autumn-winter period there was a linear relationship between the LAI and DM production in all treatments.
The rate of leaf production per tiller was significantly higher in cocksfoot than in ryegrass and tall fescue in both seasons.
New tillers had a significantly higher rate of leaf production than old tillers in the spring-summer period, but not in autumn-winter. The numbers of grass tillers and rooted nodes of clover were significantly higher under 3–1 than under 9–1 and were influenced by season.     

THE RESIDUAL VALUE OVER THIRTEEN YEARS OF ROCK PHOSPHATE AND SUPERPHOSPHATE ON A PERMANENT GRASS SWARD

Over 13 years, 12 cwt/ac of ground rock phosphate (29% P₂O₅) were applied to an old grass sward, either completely in the first year or in equal amounts in each of the first 4 years; alternatively, 18 cwt superphosphate/ac were applied either in 3 equal amounts at 4–yearly intervals, or in equal amounts annually over the first 12 years.
In the first year, the larger dressing of superphosphate gave the best response, measured as fresh herbage cut in mid–July each year, but during the next 7 years all methods of application gave similar yields. Dressings of rock phosphate gave progressively poorer response after 7 years and plots so treated were not significantly better than the control in the final year. At the end of the experiment, plots receiving annual applications of superphosphate yielded most herbage and those which had received superphosphate at 4–yearly intervals still showed a significant response. Phosphate in rock phosphate applied as a single dressing was two–thirds as effective over an 8–year period as that in superphosphate applied annually.
The small difference over 12 years in phosphate uptake from 3 dressings of superphosphate compared with its equivalent in annual applications suggested that little phosphate fixation was taking place. The fact that a single dressing of rock phosphate was able to maintain yields and phosphate uptake close to that obtained from annual applications over 7 years supports this and suggests that the failure to utilize one third of the phosphate in rock phosphate was mostly due to initial insolubility.