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.     

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 USE OF PERENNIAL RYEGRASS SOWN AT 1 LB. PER ACRE IN A STANDARD SEEDS MIXTURE

An attempt was made in a survey-type trial to combine perennial ryegrass with cocksfoot, meadow fescue and timothy together in the same sward, without the association being dominated by the ryegrass. It is concluded from this work that such non-dominant ryegrass swards can be obtained by limiting the seeding rate of the ryegrass to 1 lb. per acre in a seeds mixture sown at the rate of about 20 lb. per acre.     

RESPONSE OF GRASSLAND TO NITROGENOUS FERTILIZER IN THE WEST OF ENGLAND

Extensive replicated plot experiments were carried out at Henley Manor Farm from 1956–1961 to obtain accurate measurements of herbage production and response to nitrogenous fertilizers under West of England conditions. 356 plots were used; use of the herbage by both cutting and grazing was studied. The principal results are: Grass/ clover swards (containing approx. 35% clover) grown without nitrogenous fertilizer averaged 75 cwt dry matter per acre per annum. Application of nitro-chalk to initially grass/clover swards reduced the clover content of the herbage. About 133 lb N/annum was required by an all-grass sward to equal the production of a grass/clover sward without N. Attempts to increase production of grass/clover swards by using N for early growth and relying on clover for mid-season growth were unsuccessful in 2 out of 3 years. Swards (initially grass/clover) gave significant increases in total dry-matter production from regular use of the lowest level of N (26.0 or 34.7 lb N/acre/cut or graze) in 44 out of 49 cases. Extremely high yields were obtained from the heaviest use of N (104.2 lb N/acre/silage cut). 52.1 lb N/acre/cut or graze was the optimum rate of application on ail-grass and grass/clover swards. Up to about 350 lb N/acre/annum the dosage-response curve was very nearly straight for all-grass and grass/clover swards. On the grazed plots herbage left ungrazed amounted on average to only 6% of the total. The health of all stock on the high nitrogen plots (as well as all others) was excellent.     

THE PRODUCTION AND UTILIZATION OF WINTER GRASS AT VARIOUS CENTRES IN ENGLAND AND WALES, 1954–60

The effects of management on the production of winter grass wen studied of 47 site England and Wales from 1954 to 1958.
Cocksfoot swards provided better grazing during December and January than perennial ryegrass. The best treatment for winter-grass production from cockfoot swards was to rest from mid-August, giving un application of 52 lb of nitrogen per acre at this time.
Perennial ryegrass produced relatively high yields if rested from early September, but the herbage should be grazed before the end of November because of the risk of it rotting.
Cocksfoot herbage in normal swards lost more weight from December to January than cocksfoot sown in wide drills.
Local Factors, such as aspect, altitude and sward vigour, were generally more important than latitude in determining level of yield in December. but there were greater lovsess of dry matter from December to January in the north than in the south.     

THE INFLUENCE OF TWO LEVELS OF NITROGENOUS FERTILIZING ON THE LONG-TERM PRODUCTIVITY OF LEYS

Two levels of nitrogen application (70 and 180 lb per acre per annum) were compared on 6 long-duration leys. The treatments were repeated for periods of up to 4 years on tiie same swards. The higher N dressing produced 2230 lb more dry matter per acre than the low rate, an increase of 28%, and the yield was also more evenly spread throughout the season. There was virtually no clover on the high-N swards. The proportion of clover varied under low N but tended to increase as the season progressed. The sown grasses remained the dominant sward constituents throughout the experiment, and there was no sign of loss of vigour on the high-N swards. Utilized-starch-equivalent outputs were calculated from 3 different swards for 1956–8 and there was a significant positive correlation between the dry-matter yields and utilized-starch-equivalent output of swards.     

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 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.     

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

Seven species or varieties of grass, and a mixture of 3 of them, were sown in pure swards, treated with 4 levels of nitro-chalk (0, 17·5, 35, and 70 Ib N/ac/cut) and cut 4 or 5 times each year. Each species and the mixture were also sown with white clover, and the effect of fertilizer N on the yield of N in each grass was compared with the effect of clover on the yield of N harvested from the grass/clover swards.
The regression line for response in yield of N with increasing levels of fertilizer N showed slight, but significant, upward curvature. The grasses differed in their uptake of N from the soil, S37 cocksfoot and S48 timothy showing relatively high uptakes, and the ability of each grass to take up fertilizer N was usually related to its uptake of N from the soil. Differences in the yield of dry matter between the species, at a similar level of N, are discussed, and it was concluded that perennial ryegrasses were most efficient and Agrostis tenuis was least efficient in using the N taken up in the production of DM.
In general, there were no significant differences between the yields of N of the grass/clover mixtures; the N yields of the grass components were significantly different and tended to be inversely related to the N yields of clover.
Grasses which gave high yields of N with fertilizer were also high yielding when grown in association with clover. Pure grass swards required more than 200 Ib fertilizer N/ac/yr in order to yield the same amount of N as the grass/clover swards. The amount of N estimated to have been derived by grass from clover (indirect effect of clover) increased each year; it was highest with S37 cocksfoot and lowest with Irish perennial ryegrass, averaging 46 and 23 Ib N/ac/yr, respectively.     

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.     

A STUDY IN METHODS OF GRASS VARIETY TESTING

Methods for the appraisal of varieties in forage grasses are examined in the light of results from an experiment. Five varieties of perennial ryegrass were grown as spaced plants, broadcast swards and swards with white clover, and all were subjected to five cutting treatments during the first and second harvest year.
Spaced plants and swards gave equally good information on the order in which varieties attained maximum rate of growth in spring each year; but in respect of actual yield, the order in which varieties were placed in spaced-plant culture was reversed in broadcast swards. It is suggested that the disparity may have arisen because all varieties were sown at a common seed rate; and that spaced-plant cultures give a better indication of relative potentialities than do the majority of sward trials.
Late-maturing varieties compared better with early varieties when each variety was cut with reference to date of ear emergence than when all varieties were cut simultaneously (that is, in respect of dry matter production: at a given stage of development the early varieties had a slightly higher nitrogen content than the late). The shortcomings of both systems of cutting, and the need for comprehensive tests, are discussed.
There was little interaction between method of culture and cutting treatment in this experiment.     

Effect of dairy slurry application rate and forage type on production,soil nutrient status and nitrogen‐use efficiency

Seven forage types (diploid and tetraploid perennial ryegrass, Italian ryegrass and hybrid ryegrass, a low‐input mixture of perennial ryegrass, cocksfoot, timothy and meadow fescue, a mixture of perennial ryegrass and white clover, and monoculture of red clover) were sown in late July 2004. Each received one of four rates of dairy cattle slurry in three annual applications by trailing shoe, which supplied average nitrogen (N) inputs of 0·0, 114·9, 204·8 and 301·2 kg N ha^?1 annum^?1. Treatments were cut either three or four times annually over four years. Average dry‐matter yield (DM) response to slurry N was 15·6 kg DM kg^?1 N. Lowest recovery of slurry N was in the second application each year (after first cut). The data suggest that slurry applied to Italian ryegrass, and also to swards containing legumes on soils with high phosphorus content, will produce a lower DM response to slurry N and result in a lower slurry N recovery than on swards of perennial ryegrass or cocksfoot‐dominant low‐input mixtures. Apparent recovery of slurry N was low at the second cut, especially when first‐cut yields had been high. To maximize slurry N recovery, application to regrowths with potentially slow rates of growth or high legume content should be avoided.     

THE EFFECT OF A RYEGRASS COMPANION GRASS AND THE VARIETY OF RED CLOVER ON THE PRODUCTIVITY OF RED-CLOVER SWARDS

An experiment was conducted to measure the effects of differrat ryegrass companion grasses and red-clover varieties on the productivity of red-clover swards. Three silage harvests per year were taken over a 2-year period. The addition of a companion grass increased total herbage yields; S24 perennial ryegrass gave the highest herbage yield over the two years, followed by Reveille perennial ryegrass. Because of lack of persistence, Tetila Italian ryegrass yielded poorly the second year. A companion grass had little effect on red-clover yields in the mixed swards but improved percentage digestibility of the OM of the total herbage and lowered the CP percentage. Its presence also reduced the ingress of unsown species. The variety of red clover used had little effect on total herbage yields or red-clover yields in the first harvest year. In the second year, Hungaropoly and Tilo persisted better and so gave higher total herbage yields and red-clover yields than Dorset Marl or Essex. The fall in total herbage yields from the first to the second year was entirely due to a fall in red-clover yield since yields of the ‘non-red clover’ fraction of the total herbage increased. A red-clover/grass sward may have advantages over a pure red-clover sward nutritionally, for silage-making and for its effect in diluting the oestrogenic activity of a pure clover sward. A major reappraisal of the role and potential of red-clover swards in the UK is warranted because of their many valuable attributes, particularly their ability to give high herbage yields of high nutritive value without the addition of fertilizer N. The improved persistency of some of the tetraploid varieties of red clover enhances the value of the plant.     

THE EFFECT OF WEEDS, AND THEIR CONTROL BY MCPA SPRAYING, ON THE ESTABLISHMENT OF PERENNIAL RYEGRASS AND COCKSFOOT IN THE KENYA HIGHLANDS

The vigour of perennial ryegrass and cocksfoot after spraying with the sodium salt of MCPA during establishment was estimated from their yields in small-plot cutting experiments on weedy land. Where the weed yields of control plots was of the order of a ton of air-dry matter an acre (mostly Spergula arvensis L.), spraying at up to 1·2 1b. acid equivalent an acre caused twofold to threefold increases in grass yields. The optimum time to spray perennial ryegrass was at the three- to four-leaf stage or 26 days after sowing; for cocksfoot, which appeared more susceptible to the herbicide, spraying at the tillering stage, or about 40 days after sowing, was best. Increasing the seed rates of ryegrass produced transitory increases in yields while decreasing weed yields. Increasing phosphate or nitrogen caused decreases in weed yields. Although the former gave a large increase in weed yield in the first cut this was offset by a large decrease in the second cut. There was an indication that the level of nitrogenous manuring affected the toxicity of the herbicide to the grasses.     

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 production.
Data from the grass-alone swards allowed an estimate to be made of the effect of N on production at different cutting dates. This was compared with the effect of clover.
The effect of N was greater than that of clover in the mid- and late-season cuts. Clover made its greatest contribution, both directly and indirectly, at the first cut, taken in May.
Under very dry conditions (1959), N was more effective than clover in maintaining production and the proportional response was large in relation to that produced under moist conditions.
The results are discussed with reference to the present seasonal use of N on grassland and an argument is advanced for increasing its use in mid-season.     

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 PRODUCTION AND USE OF COCKSFOOT FOGGAGE FOR WINTER GRAZING IN SOUTH-WEST SCOTLAND

The production and use of cocksfoot foggage for winter grazing at the Hannah Dairy Research Institute in the period 1956–61 is described. Two acres of cocksfoot (S37) were sown broadcast in 1956 and two acres were drilled in rows 28 in apart in 1957. The average annual application of fertilizer nutrients was 118 lb. N, 51 1b. P2O5 and 142 lb. K2O per acre.
The mean yield of the broadcast section was 7450 lb. dry matter/acre/annum compared with 6090 lb. from the rowcrop section. Normally two crops of grass were harvested from the field in the summer, and one grazing was made in the winter. The yield of winter herbage dry matter was 28% and 26% of the total annual yield of the broadcast and the rowcrop sections, respectively.
The field was grazed for four successive winters by 5–10 bulling heifers each weighing 650–850 lb. They received no other feed during the grazing period. Grazing started in December and finished in February, March or April in different years. The mean intake of herbage dry matter was only 6 lb./day, and on average the heifers lost 80 lb. liveweight each winter. This loss was regained after 4–6 weeks when the winter grazing finished. Twenty-nine of the 30 heifers held to the first or second service while grazing the winter herbage.
On average the broadcast section gave 340 heifer-grazing-days per acre during the winter and the rowcrop section 260 days. The cost of a heifer-grazing-day was 3id. and 4id. on the broadcast and rowcrop sections, respectively.
The dry matter of the herbage cut on 19 December 1960 had a digestible crude protein content of 59% and a starch equivalent of 34.
It is concluded that on well-drained land the technique of foggage production and of winter grazing can usefully extend the normal grazing season and hence reduce the costs of winter feeding.     

WILD WHITE CLOVER SEED PRODUCTION

Field experiments on the management of ryegrass/white-clover pastures for seed production were carried out from 1958 to 1961. Replicated trials with ¹/₆-acre plots compared continuous grazing, rotational grazing and cutting once at the silage stage of growth as methods of pasture management from April to June. An additional mechanical method, gang mowing, was introduced in 1960 and Hayter mowing was used in 1961. In 1958 to 1960 the treatments were studied with and without the application of 70 lb nitrogen per acre. Clover flower heads per square foot, clover seed and ryegrass seed yields were greatest under continuous grazing, although in some years comparable results were obtained from the mechanical defoliation treatments. There were substantial differences between potential and harvested clover seed yields, the latter ranging from 20% to 75% of the potential yield. The weight of ryegrass seed harvested was highest under continuous grazing and least under the cutting treatments. The nitrogenous fertilizer increased the production of herbage dry matter and of ryegrass seed, but greatly reduced clover seed yields. The results are discussed in relation to the influence of weather on the incidence of flowering and the influence of methods of defoliation on flower-bud emergence. It is concluded that mechanical methods of defoliation can produce yields similar to those obtained under continuous grazing, provided that cutting is carried out at the correct stage of growth.     

Production performance and meat quality of grazing lambs finished on red clover, lucerne or perennial ryegrass swards

The combined benefits of a high crude protein concentration, and possible protein protection and growth‐promoting properties, make forage legumes potentially attractive as a natural means of increasing liveweight gain and time to slaughter of lambs in lamb finishing systems. An experiment was conducted to compare the production performance and meat quality of grazing lambs finished on red clover (Trifolium pratense), lucerne (Medicago sativa) or perennial ryegrass (Lolium perenne) swards. Replicate (n = 2) swards of red clover, lucerne and perennial ryegrass were rotationally grazed by ten ram lambs and ten ewe lambs from weaning until selection for slaughter at UK fat class 3L. Lambs grazing the red clover sward had a significantly higher liveweight gain and required significantly fewer days to slaughter than lambs grazing the lucerne sward (305 g d^?1 vs. 243 g d^?1; 38 d vs. 50 d), which in turn had a higher liveweight gain and required fewer days to slaughter than lambs grazing the perennial ryegrass sward (184 g d^?1; 66 d). Lambs grazing the red clover and lucerne swards had significantly higher herbage intakes than those grazing the perennial ryegrass sward (2·06, 1·72 and 1·16 kg DM d^?1 respectively), but in vivo digestibility of herbage was similar. Lambs grazing the red clover and lucerne swards also had significantly higher serum urea concentrations than those grazing ryegrass (12·5, 11·1 and 6·2 mmol L^?1 respectively). Killing‐out percentage was significantly higher for lambs grazing the red clover sward than for lambs grazing the perennial ryegrass sward (48% vs. 46%). There were no significant effects of finishing system on meat flavour, but meat from lambs finished on the lucerne sward was oxidatively less stable than that from lambs finished on the perennial ryegrass sward. Grazing the forage legume swards significantly increased the proportion of linoleic and linolenic acid in muscle tissue, and therefore the proportion of unsaturated to saturated fatty acids (0·19, 0·16 and 0·12 for the red clover, lucerne and perennial ryegrass swards respectively). However, the n?6/n?3 ratio was significantly lower for the muscle of lambs grazing the perennial ryegrass sward compared with those grazing the forage legume swards (1·13, 1·08 and 0·98 for the red clover, lucerne and perennial ryegrass swards respectively). The results indicate that by grazing lambs on forage legume swards it is possible to increase individual lamb performance without compromising meat quality.     

Effect of supplementation on production by spring-calving dairy cows grazing swards of differing clover content

An experiment was carried out to examine the effect of supplementation on the performance of spring-calving dairy cows grazing swards of differing perennial ryegrass and white clover content. Seventeen heifers and sixty-four Friesian cows in their third to ninth week of lactation were turned out onto one of three pastures with different proportions of perennial ryegrass and white clover. Nine animals on each pasture received either 0, 2 or 4 kg d⁻¹ of a concentrate with a crude protein concentration of 180 g kg⁻¹ dry matter (DM). Prior to grazing, swards contained proportionately 0·01 (L), 0·15 (M) and 0·20 (H) of total DM as clover. During the experiment, grazing pressures were adjusted by movement of buffer fences to maintain compressed sward heights at 6 cm. Samples taken 26 and 68 d after the start of grazing showed little change in the proportion of clover in sward L (< 0·01 and 0·02 respectively), but convergence in the proportion of clover in swards M and L (0·08-0·16 and 0·10-0·15 respectively). Mean daily yields of milk, fat, protein and lactose increased significantly with increased clover content and, even without supplementation, daily yields were 25·4, 0·98, 0·73 and 1·09 kg respectively on sward H. Of the milk components, only protein was significantly increased by increasing sward clover content. The response in milk yield to supplementation was greater on sward L than on swards M and H.