RED CLOVER SILAGE FOR MILK PRODUCTION

Nine wilted silages made from tetraploid red clover were fed in four winter-feeding experiments to 32 Ayrshire cows. The DM content of the silages averaged 23±5% (range 15±8–27±1) and contained an average of 19±6% crude protein, 14±2% digestible crude protein and 52±0% digestible organic matter. The pH values varied from 4±0–6±2, depending on the DM content and mechanical treatment of the crop, and the rate of application of formic add. The silages were fed ad lib.with supplementary concentrates and the average daily intakes of silage DM ranged from 16±0–24±0 Ib/cow (7±3–10±9 kg). The highest daily intakes were obtained with double-chopped silage containing 24–26% DM with a pH of 4±0. Although the red-clover silage had a high content of N and apparently provided a balanced ration with the addition of barley, yields of milk were increased significantly by substituting 1 Ib (0±4 kg) groundnut cake for 1 Ib barley in the daily ration of the cow. The silage contained oestrogenic compounds but the breeding pattern and fertility of the cows were not affected adversely. The tetraploid red clover produced approximately 9000 Ib DM/ac (10 100 kg/ha) in the 1st-harvest year and it is concluded that a safe and highly palatable silage with high intake characteristics can be made if the clover is wilted to about 24% DM, double chopped, and formic acid is applied at the rate of 0±5 gal/ton.     

简易超干燥芝麻种子贮藏方法的研究

采用木柜、干燥器和冰箱贮藏方法，对芝麻种子贮藏的效果进行了研究，结果以冰箱低温贮藏效果最佳，但成本高；其次是干燥器贮藏，干燥器内贮藏１７年的种子，含水量稳定在２．３％左右，粗脂肪、粗蛋白和脂肪酸组成含量未发生明显变化；田间种植出苗率仍在５０％以上，且能正常生长，无形态上的变异。     

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.     

WILD WHITE CLOVER SEED PRODUCTION

A survey, covering some 140 fields, totalling 1540 acres, in Kent was conducted in 1961 on the effect of different methods of management on yields of perennial ryegrass and white clover seed. The main results were: (a) the majority of seed growers harvested seed from short-term leys and only a limited acreage of permanent pasture was used for producing seed. Yields of both ryegrass and clover seed were considerably higher on the younger leys; (b) the highest seed yields in 1961 were obtained from fields where sheep grazing was stopped on 24 May. However, a large number of growers continued sheep grazing well after this date: (c) mechanical defoliation, especially when used to supplement sheep grazing, proved an effective method for producing high yields of clover seed; (d) honey bees are important in increasing seed yields, particularly on recently sown leys; (e) combine harvesting from the swath was the most common method of harvesting and no instance of the use of tripods was reported. Seed yields from baling methods were generally low, but direct combining produced a high average yield of clover seed. From these results it was concluded that there was much scope for raising the general level of clover seed yields, especially by giving greater attention to details of management.     

THE USE OF HERBICIDES IN WHITE CLOVER SEED CROPS

The effectiveness of 4 herbicides in restoring the dominance of white clover in an old grass/clover sward was tested at Cambridge during 1963–5. The best results were obtained with applications of paraquat at 1 and 1 1/2 Ib/ac at the early stages of clover growth in spring. Both the dominance of white clover and the yield of seed were increased significantly.
Dalapon also increased the proportion of clover in the sward but tended to retard flower- and seed-formation. MCPB and WL5792 failed to change the proportion of clover or its seed yield.     

THE EFFECTS OF SEED RATE, CLOVER AND APPLIED NITROGEN ON BROADCAST SEED CROPS OF PASTURE RYEGRASS

This investigation was carried out with leafy varieties of perennial ryegrass at four centres near Aberystwyth over a period of three years. Nitrogen applied in spring increased lodging, the number of fertile tillers and also seed yield, except where sowing was made without a cereal cover crop. While reasonable yields were obtained from badly laid crops, it is suggested that lodging prior to anthesis has an adverse effect on seed yield. Clover included as a companion species tended to depress the yield of seed and increase the degree of lodging.
Seed rate had less infiuence on lodging and seed yield, but the data show that similar yields were obtained from light seed rates of 4 lb. per acre as from the heavier rates. On the other hand, there was a tendency for the low rate of seeding to produce weedy plots, especially when sown in the absence of a cover crop.     

THE CONSUMPTION OF PERENNIAL RYEGRASS AND RED CLOVER BY GRAZING LAMBS

Groups of six-month old lambs, which were either experienced or inexperienced grazers, strip-grazed swards of S24 perennial ryegrass or Hungaropoly tetraploid red clover, at daily herbage allowances of 20 or 40 g OM/kg LW, in late August and September. The swards were similar in N content, but the weight of standing crop, and its digestibility, were higher on grass than on clover. Estimates of herbage intake were made in two successive periods of 19 days. Intake (g OM/kg LW) was lower at low than at high allowance (by 22% and 28% in periods I and II). and experienced grazers ate more than inexperienced animals (by 27% and 22%). Intakes on clover were 28% higher than on grass in Period I, but in Period II the difference was not significant.     

POTENTIAL PRODUCTIVITY OF RED CLOVER VARIETIES IN S.W. SCOTLAND

A reassessment of the potential productivity of 37 varieties of red eiover suggests that DM productivity is equivalent to grass given fertilizer N at 252 kg/ha for the 1st year, 209 kg/ha for 2nd year and 144 kg/ha for 3rd year of production. Corresponding equivalents for CP productivity of the red clover swards were 298, 228 and 206 kg N/ha. Varietal differences in productivity were significant Average yields of total herbage DM in the 1st, 2nd and 3rd harvesting years were 10.9, 8.7 and 8.2 t/ha, containing 6.5, 5.9 and 6.0 t/ha red clover, respectively. For two harvesting years, the most productive varieties were Essi, Kuhn, Hungaropoly, Robina, Tilo Daehnfeldt, Redhead and Corona Otofte. Rea 4N and a few other tetraploid varieties were very productive in the 3rd year. Hungaropoly, although showing a decline in the 3rd year, was the most productive over 3 years, with an average yield of 11.5 t/ha per year total herbage DM containing 10.2 t/ha per year red clover DM. Such high potential DM production warrants further investigation into the persistence of red clover, its conservation and the problems of its utilization by livestock.     

THE EFFECTS OF LONG-TERM STORAGE ON THE VIABILITY OF S23 PERENNIAL RYEGRASS SEED AND ON SUBSEQUENT PLANT DEVELOPMENT

Eight lots of seed of S23 perennial ryegrass which had been artificially dried to different moisture levels and stored for 20 years were tested for germinating capacity, and the effects of long-term storage on subsequent plant development were studied. The results of the germination tests indicated a continuation of the downward trend in viability previously reported. Observations on the derived mature plants revealed no difference between lots in general growth habit; a few seedlings showed symptoms of some retardation in growth but most plants manifested the high tillering and prostrate growth typical of S23 perennial ryegrass. Pollen fertility was markedly reduced in 38% of all the plants sampled. The seed-setting capacity was affected to an even greater extent, 44% of the plants giving seed-set values decidedly below those obtained for plants grown from new seed. Where pollen fertility had been much reduced, seed-setting also was usually low, but there were some instances of satisfactory pollen fertility associated with a low seed set.     

常温条件下花生种质资源超干燥贮藏研究

不同含水量的花生种子在常温下，密封干燥贮藏7、9、11、12a，对其种子发芽率、发芽势、活力指数、植株生长发育以及植物学特性和经济性状有不同程度的影响。在武汉气候条件下，花生种子含水量处于3．2％～3．3％的超千状态下，至少可安全贮藏11年。     

HARVESTING TETRAPLOID RYEGRASS FOR SEED

Sequential harvests of two tetraploid ryegrasses have shown that the commercially critical level of 90% germination was attained early in the ripening process. For the greater part of the maturation period the moisture level was maintained at 60% as in diploid grasses, but the rate of moisture loss during the latter part of ripening proved to be slower than in diploids. The large seeds are more susceptible to mecbanical damage at harvest and therefore require lower drum speed.     

THE EFFECT OF LEAF NUMBER ON THE SENSITIVITY OF RED CLOVER SEEDLINGS TO PHOTOPERIODIC INDUCTION

The duration of the juvenile phase in early-flowering (Dorset Marl) and late-flowering (S123) red clover is described. Neither cultivar responded to inductive conditions at the first leaf stage but Dorset Marl attained maximum sensitivity by the 3-leaf stage. A comparable response was obtained with S123 only after the production of 12–13 leaves. The growth characteristics of the two types under continuous long or short days are described and possible explanations are advanced for the characteristic differences in tillering and stem internode number.     

红壤施用石灰石粉对芝麻产量的影响

石灰石粉施用量的试验结果表明:(1)随着石灰石粉用量增加,土壤pH升高,交换性铝和铝饱和度下降。施后7年仍可发挥其效果。(2)施用石灰石粉,显著增加每株蒴数和千粒重,增产幅度为17％—6l％。(3)土壤pH升高到6.0以上、交换性铝含量降至1.0me/100克土以下,芝麻才能获得较高的产量。     

THE EFFECT OF FEEDING RED CLOVER CONSERVED BY DRYING OR ENSILING ON REPRODUCTION IN THE EWE

Forage diets were prepared from ryegrass (non oestrogenic control) and from red clover as pellets or as unwilted silage. Each diet was fed to separate groups of 20 Border Leicester × Cheviot ewes for three weeks prior to the introduction of the ram, and for two cycles after mating. Subsequently, all three groups of ewes were fed in a similar manner until lambing and the reproductive performance of the ewes was measured. The control diet was prepared by barn drying a primary growth crop of perennial ryegrass, Lolium perenne cv S23. Tetraploid red clover, Trifolium pratense cv. Hungarpoly, was harvested as a first regrowth crop and the pelleted diet prepared by high temperature drying, grinding (2 mm screen) and pelleting. The silage was prepared without wilting. The level of formononetin in the red-clover silage was three times that in the dried red-clover pellets. Compared with the control grass diet, the feeding of red clover in either form significantly reduced (P<0·001) the number of lambs born. The incidence of barrenness was higher (P<0·001) for ewes fed red-clover silage compared with red-clover pellets and the control diet. The rate of twinning was significantly (P<0·001) higher for the ewes fed the control grass diet than for either of the red-clover diets. The resultant lambing percentages were 190,165, and 100% for the control grass, red-clover pellet and red-clover silage treatments. In flock management, both the grazing of red clover and the feeding of red-clover pellets or silage, prior to and during mating, should be avoided.