ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1970.tb00599.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

ABSTRACTThe effect of a range of N rates on herbage production from grass/white‐clover and grass swards was investigated in two long‐term grazed experiments. The mixed sward yielded more than the grass swards over the range of fertilizer rates tested which were 0–120 lb N/ac (134.5 kg/ha), but the response of the mixed sward to fertilizer N was less than that of tbe grass sward. Tbis was due to the direct and indirect effect of clover, which was considerable with no fertilizer N but decreased witb increasing rates of application. However, clover was not completely suppressed by N at eitber site and contributed to berhage yields at all N rates.Rate and time of N application and the amount of clover in tbe sward affected tbe seasonal distribution of DM yields. The mid‐season decline was less marked at bigb‐ tban at intermediate‐levels

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1970.tb00600.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

ABSTRACTTwo contrasting levels of N were applied in natrient solution to dense stands of cocksfoot plants grown in tins in controlled‐environment cabinets. During a 12‐week period of growth in a constant environment a full growth analysis was carried out. High N caused a three‐ or four‐fold increase in total dry weight per unit area by doubling shoot number and increasing shoot weight by approximately 60%. The increase in shoot weight arose mainly from a large Increase in leaf and sheath weight per shoot; root weight per shoot was for the most part negatively affected by high N. The large positive effect of N on leaf weight resulted from the development of slightly wider and much longer leaves, which had a similar or greater weight per unit area of leaf than equivalent leaves from the low‐N treatment.The effect of high N on total dry weight was the consequence of a superior NAR and, in the first half of the experiment, a superior LAR. The physiological implications of the effects of high levels of applied N on DM production in the field are discussed. ice and

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1970.tb00601.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

ABSTRACTThe effects of preeropping with Italian ryegrass and tall fescue mixtures on marrow‐stem kale (1st test crop) and barley (2nd test crop) were measured.Application of N to the grass/clover swards reduced the yield of DM, P, K, Na, Mg, crude protein and also the percentage crude protein in the kale test‐crop.Following the tall fescue swards, the yield of DM, P, Na, Ca, Mg and E, crude protein and percentage crude protein in the kale were lower than after the Italian ryegrass swards. These effects were particularly evident in the kale stem.Interactions occurred which involved the method used to establish the herbage mixtures, the application of N to the swards and of fertilizers to the kale. These effects were complex, but the method of sward establishment could clearly affect the following kale crop grown several years later.The influence of grass swards on the second test‐crop (spring barley) was much smaller than on kale. Precropping with Italian ryegrass or using a cover crop during grassland establishment reduced 1000‐grain weight of barley. The crude protein percentage in barley grain was reduced by the compound fertilizer applied to the previous kale crop, particularly when no cover crop had been used during establishment of the herbage mixtures. The converse of these effects was recorded in the crude‐protein percentage of the straw of the barley

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1970.tb00602.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

ABSTRACTWhole crops of barley were conserved and fed to sheep and cattle. In the first experiment the barley was cut at the mealy‐ripe stage of growth and conserved by ensilage or by drying artificially. Cattle and sheep lost weight when the resulting silages were fedad lib.;wilting the crop before ensiling did not improve the performance. Sheep fed artificially‐dried whole‐crop barley increased in liveweight; and the intake of this was significantly higher than that of the silages.In the second experiment, barley was cut and ensiled at the watery‐ripe, mealy‐ripe and late mealy‐ripe stages of growth. Intakes and levels of performance by sheep fed these silages did not differ with the growth stage at which the crop was harvested, but supplementation of the silages with lucerne pellets resulted in large improvements in

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1970.tb00603.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

ABSTRACTThree grass‐ and two lucerne‐based harvest schedules were applied to pure sowings of timothy, smooth hrome grass, lucerne and the single grass/lucerne mixtures. Harvesting at the medium‐bud stage of development of lucerne was selected as the criterion which provided the highest DM yield in conjunction with high and consistent levels of rVD and CP from harvest to harvest, as well as persistence of the species in the pure sowings of lucerne/grass mixtures. On the same basis, the heads‐emerged stage of development proved most satisfactory for harvesting pure sowings of timothy and hrom

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1970.tb00604.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

ABSTRACTThe growth of calves grazing pure swards of perennial ryegrass, timothy and meadow fescue at low grazing pressure was measured. Organic‐matter intake was estimated on three occasions during the grazing season. In 1963 rest periods of 7 days in April and May and of 21 days in June‐Octoher were used hetween 7‐day grazing periods. In 1964 the effect of long (35–55 days) and short (15–25 days) rest periods hetween 3.5‐day grazing periods were compared. There were no measurable differences in intake hetween the calves on the three grass species in 1963. In 1964 faecal production was higher with timothy than with the other species and with small differences in digestihility, the intake on this species was higher. The faecal production and intake were higher, hut not significantly so, with the long‐rest management in the second year. The liveweight gains of the calves grazing the three species were similar in 1963; in 1964 gains with meadow fescue were lower than with the other species from 13 April to 22 June but this was the only significant difference. The results obtained on slaughtering the calves at the end of each summer

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1970.tb00605.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

ABSTRACTTwo grass sUages made in June and two made in September, all from the same field, were compared in a 16‐week winter‐feeding experiment with 12 Ayrshire cows. The silages were fedad lib. with a supplement of barley and groundnut eake. One of the sUages made in June and one made in September had been treated with 1/2 gallon of formie acid per ton of herbage when cut, whereas the other two silages were untreated. The contents of digestible organic matter in the silage DM made with and without the acid additive were 67.4 and 63.8%, respectively, in the June silage, and 66‐1 and 62.7% in the September silage. The intakes of silage and total DM were higher in the treatments containing the acid‐treated silages than in those containing the untreated silages. The mean daily milk yields from cows fed on the sUages made with and without the additive were 36.3 and 33.8 lb (16.5 and 15.3 kg), respectively, for silages made in June, and 35.4 and 34.1 lb (16.0 and 15.5 kg) for those made in September. The solids‐not‐fat (S.N.F.) contents of the milk averaged 8.60 and 8.50% respectively, from the silages with and without the additive. It is concluded that the silage with the formic‐acid additive was superior to the untreated silage as a feed f

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1970.tb00606.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1970.tb00607.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

ABSTRACTThe problems of designing, conducting and interpreting the results of grazing trials to evaluate tropical pasture mixtures are discussed in relation to an experiment wbich measured the effect of three fixed stocking rates upon two grass/legume pastures. A uniformity trial prior to grazing indicated considerable soil variability, which necessitated ground replication. Sequential grazing of three pasture replicates at a fixed stocking rate and a fixed interval of grazing resulted in sites of low fertility being heavily penalized. Such a form of replication was of value for measuring the effect of treatments upon sward composition, and, to a lesser extent, variation in animal production, within the experiment area. Differences in animal production between pasture species were small when compared with the effect of various stocking rates, emphasizing the need for an objective assessment of stocking rate when evaluating pasture species. Fixed‐stocking‐rate designs have more general application in the tropics because they are easier to conduct, and the results are repeatable and can be extrapolated to farm pract

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1970.tb00608.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY