THE USE OF THE FORAGE HARVESTER IN THE IMPROVEMENT OF ROUGH GRAZING

Considerable improvement has been achieved in rough grazings by fairly frequent close mowing with the forage harvester or flail mower, particularly when combined with manuring and surface seeding.
The implement has proved capable of tackling very tough vegetation and converting it into grazing swards of fair value and good botanical composition. Undesirable species have been largely eliminated by treatment over two growing seasons.
The method is believed to compare favourably in cost with sward renovation by cultivation or by herbicides.     

INTERACTIONS OF GRAZING AND BURNING ON HEATHER MOORS AND THEIR IMPLICATIONS IN HEATHER MANAGEMENT

In order to study the interaction between burning and grazing on heather areas, an experiment was set up in which six paddocks were subjected to different systems of controlled grazing. One quarter of each paddock was burned at two-yearly intervals. The effects of burning and grazing on the regeneration of the vegetation are described. The chemical composition of heather is known to change with age and season; in this experiment grazing was shown to have an effect also. The amount and earliness of the growth of the current season's shoots of heather were affected by both age of plants and grazing intensity. This result was thought to be related to temperature gradients near the ground. Sheep did not graze the sub-plots of different age within each paddock evenly; more recently burned sub-plots were preferred, the preference being most marked with the grazing regimes of lower intensity. At the highest grazing intensity the older and younger sub-plots were grazed to a similar extent. It is concluded that, in addition to controlled burning, effective management of heather moors must include some measure of grazing control.     

THE EFFECT OF DALAPON ON THE SPECIES OF HILL GRASSLAND

The effect of dalapon is described on pastures of Agrostis/Festuca, Festuca ovinal Deschampsia flexuosa and related Nardus- or Molinia -rich hill grasslands. The results are discussed in relation to the technique of surface sowing and the choice of vegetation types suitable for treatment.     

THE EFFECT OF FERTILIZER AND GRAZING ON THE BOTANICAL COMPOSITION AND OUTPUT OF AN AGROSTIS/FESTUCA SWARD

The results are reported of the effects of fertilizer and grazing or cutting for hay over a period of 6 years on the composition of an Agrostis/Festuca permanent pasture on low-lying land at Beghroke Hill. Applications of N up to 264 units/ac each year associated with frequent defoliation every 21 days produced only small changes in sward composition; Agrostis spp. declined and Poa trivialis increased. Lolium perenne did not increase from a small initial presence. Records of animal performance and hay yield showed that the mean output from the experiment as a whole was 530 Ib liveweight gain/ac and 0·5 ton hay/ac.     

THE EFFECT OF THE GRAZING ANIMAL ON THE N STATUS OF GRASS SWARDS

Thirty-one sets of N yield data were considered, taken from seven experiments grazed by sheep. N yield could be explained in terms of fertilizer N rate, an estimate of soil N and an interaction between the two. Fertilizer N increased grass N yield more on grazed swards than on cut swards, and this effect was greatest on soils with high available soil-N. It is concluded that N recircula-tion can be substantial on heavily-stocked swards receiving high rates of fertilizer N, so increasing the efficiency of fertilizer as a source of N in these conditions.     

除草剂对大豆幼苗根腐病及其土壤微生物的影响

两种除草剂中,地乐胺可降低大豆幼苗、根腐病的发生,而乙草胺可国重大豆根腐病的发生,在施工初期（１０天左右）土壤中各和睦具菌被抑制,细菌数量增加;后期地乐胺处理区Ｐｅｎｉｃｉｌｌｉｕｍ和细菌的相对数量有所增加,而乙草胺处理区Ｆｕｓａｒｉｕｍ,Ｒｈｉｚｏｃｔｏｎｉａ数量有所增加,Ｐｅｎｉｃｉｌｌｉｕｍ和细菌的活性被抑制。     

THE EFFECT OF WINTER GRAZING BY SHEEP ON SPRING AND EARLY SUMMER PASTURE PRODUCTION

Studies were made in S.W. Scotland of the effect of winter grazing (October to March) by sheep on subsequent spring and early summer pasture production from a sward in its first harvest year and from a permanent pasture. Averaged over the two swards, DM yields in April, May and June were reduced by 38%, 8% and 5%, respectively, as a result of various times and frequencies of grazing, compared with no grazing. Reductions were greatest after grazings in the January to March period, especially grazings involving the month of March. In a trial in which fertilizer N was used to compensate for March grazing, 50 kg NJha raised DM yields in April to the level of those from no grazing, while only 15 kg NJha were needed to raise June yields to parity. Controlled winter grazing of sheep and the use of fertilizer N to restore production losses after early spring grazing are justified.     

THE EFFECT OF STOCKING RATE ON ANIMAL PRODUCTION FROM CONTINUOUS AND ROTATIONAL GRAZING SYSTEMS

Liveweight and wool production data are presented from a grazing management experiment in which continuous stocking was compared with a four-paddock rotational system at three stocking rates on a sown pasture. Significant differences were recorded in liveweight and wool production between stocking rates. The overall effect of management was non-significant but its interaction with stocking rate and year were both significant. At the intermediate stocking rate (8 wethers/ac, 20 wethers/ha) increases in both liveweight and wool production were recorded for the rotational management system; in this treatment there was also less need for supplementary feeding. Greater wool production was recorded from the continuously grazed treatments at both the high and the low stocking rates but there was little effect on liveweight or the need for supplementary feeding.     

THE EFFECT OF NITROGEN, STOCKING RATE AND FREQUENCY OF GRAZING BY BEEF CATTLE ON THE OUTPUT OF PASTURE

Two successive grazing experiments were conducted over 12 weeks on perennial ryegrass pastures with 50 and 44 young cattle to study the effect of N fertilizer when applied at a daily rate of 1 or 3 kg N/ha. At each level of N two stocking rates differing hy 20% were imposed. At the liigher N level and stocking rate, three frequencies of grazing were imposed. At the stocking rates imposed N tended to reduce the daily liveweight gain per head, but increased the total liveweight gain per ha by from 0.79 to 1.58 kg/kg N. A 20% increase in stocking rate depressed gain per head in both years. In the first year it did not improve gain/ha, hut in the second year gain/ha was increased by 12–17%. There was a tendency for performance per animal and per ha to increase as the grazing cycle was lengthened. In 1969 the highest yield in the whole season was 1880 grazing days and 1260 kg gain/ha. The overall response to N fertilizer was similar to that recorded in other reports, but it is possible that a lack of K had limited pasture growth.     

THE EFFECT OF PHYSIOLOGICAL STATUS ON DIET SELECTION BY GRAZING EWES

The effect of the physiological status of grazing ewes on diet selection was studied, using ewes with oesophageal fistulae. The diets of dry ewes grazing Phalaris annual grasses and subterranean clover pastures, over a range of availabilities, were compared with those of ewes in various stages of pregnancy and lactation. There were no significant differences at any stage of reproduction in the botanical composition of the diets. However, small differences in diet digestibility, soluble carbohydrate and nitrogen content were found during pregnancy and lactation. These occurred at all levels of availability of pasture. The differences did not appear to have nutritional significance in the particular pasture ecosystems studied because levels of N, soluble carbohydrates and digestibility of the diet were such that selection for survival was unlikely to be necessary.
It is concluded that dry fistulated ewes can be used to obtain samples for assessing diet N and soluble carbohydrate contents for ewes in other physiological states. The use of in vitro digestibility tests of diets of dry ewes to assess diet digestibility for ewes in other physiological states may be subject to error.     

重迎茬对大豆化学品质的影响

在中国黑龙江省６个不同生态区设置固定轮作场圃，连续３年研究重迎茬大豆蛋白质、脂肪的变化情况。结果表明，迎茬和短期重茬对大豆蛋白质、脂肪含量无明显影响，重茬３年以上，蛋白质含量增加，脂肪含量降低。农艺措施对重迎茬大豆蛋白质、脂肪含量没有明显的影响，化学调节剂以重迎茬大豆蛋白质、脂肪含量有一定的影响。     

THE EFFECT OF NITROGEN, STOCKING RATE AND GRAZING METHOD ON THE OUTPUT OF PASTURE GRAZED BY BEEF CATTLE

An experiment was conducted in 1971 and 1972 to study the effects of two levels of fertilizer N (50 and 504 kg/ha) on the productivity of pastures grazed by young beef cattle. Two stocking rates were imposed at the lower N level and three at the higher. In addition to rotational grazing, set-stocking and an integrated grazing-conservation system were included. The responses/kg N were approximately 1 kg live-weight gain, 19–24 Meal ME and 8–9 kg DM. Maximum yields of 1200–1300 kg live-weight gain/ha and 25,000–27,000 Meal ME/ha were recorded. Productivity of set-stocked pasture was similar to rotational grazing at the high N level, but lower at low N. The integrated system yielded comparable results to high-N rotational grazing. Performances and herbage intakes per animal reflected the stocking rates imposed.     

除草剂对优质大豆品质的影响研究

选用土壤处理剂豆磺隆、乙草胺，茎叶处理剂普施特、虎威、拿捕净等5种除草剂，以及黑龙江省优质高蛋白大豆品种黑农35号和东农42号，高油大豆黑农41号等3个大豆品种。研究除草剂对优质大豆品种品质的影响。试验结果表明，5种除草剂正常施用剂量和加倍剂量处理，优质大豆蛋白质含量和油分含量会有一定的增减，但方差分析表明和不施药对照差异不显著。     

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.     

WHITE CLOVER AND HILL LAND IMPROVEMENT

As a preliminary step in the development of improved bred varieties an examination has been made of the factors which contribute to the success or failure of white clover ( Trifolium repens ) in hill land reseeding. Severe restrictions are placed on clover performance and N fixation in many hill areas in Britain by the poor climate, the low pH and exchangeable base status of the soils and the low frequency of effective indigenous Rhizobium strains.
Agronomic solutions to some of these problems exist, but experience in mid-Wales suggests the need for new bred varieties with improved adaptation to the prevailing conditions, particular attention being directed to the limitation of N fixation by low soil temperature.     

A PORTABLE-CORRAL TECHNIQUE FOR MEASURING THE EFFECT OF GRAZING INTENSITY ON YIELD, QUALITY AND INTAKE OF HERBAGE

A grazing experiment using four stocking rates of sheep, equivalent to 34, 45, 57 and 68 sheep/ha on an assumed 200-day grazing season, was conducted using a portable grazing corral technique. Plots were subjected to fotir grazing periods between mid May and early September. The effect of stocking rate on herbage yield and quality and the influence of these factors and feed intake on liveweights of the sheep were recorded. The mean daily herbage organic matter available over the trial was 9.6, 5.8, 3.3 and 23% of the total liveweight of the sheep at each of the four stocking rates. The highest grazing pressure led to the production of high-quality herbage, but also led to reduced productivity, low feed intake and liveweight losses. The most lenient grazing pressure failed to provide adequate herbage utilization. Even at the most intensive stocking pressure, only 66% of the herbage available to ground level was utilized in grazings after July. Intake results suggested that sheep of 45 kg liveweight required 1000–1200 g digestible organic matter per day to maintain body weight. Despite the higher in vitro digestibility of herbage on offer at the higher stocking rates, intake was limited through lack of herbage; a high degree of correlation existed between herbage availability and herbage intake over the four stocking rates and at all grazings. It is concluded that the portable corral technique is well suited for grazing studies and the assessment of sward response to varying stocking rates and is particularly useful where facilities for more extensive studies are limited.