ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1986.tb01796.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractThe nylon bag technique was used to measure the disappearance of dry matter, nitrogen and non–nitrogenous dry matter from samples of forage rape leaf and stem incubated in the rumen of sheep. Samples were either hand–harvested and chopped or obtained using Iambs with oesophageal fistulae.Differences were observed in the dry matter and nitrogen contents of oesopha1 fistulae extrusa and cut samples; calculations are presented to suggest that these differences were not due to salivary contamination. Compared with cut samples, oesophageal fistulae extrusa had significantly higher initial disappearance, fractional rate of disappearance and predicted disappearance of both dry matter and nitrogen. Observed disappearances from leaf and stem extrusa after 24 h incubation were: dry matter from leaf 0·898 and from stem 0·832; nitrogen from leaf 0·942 and from stem 0·910. Corresponding values for cut leaf and stem were 0·817, 0·726, 0·883 and 0·849, respectively.The rumen degradation of protein (nitrogen × 6·25) was computed for all combinations of leaf, stem, cut and extrusa samples for rumen fractional outflow rates ranging from 0·02 to 0·09. Degradation levels computed from cut samples were much less than those based on oesophageal fistulae extrusa and are suggested to be underestimates. Rumen degradation levels for forage rape leaf and stem were very similar and ranged from 0·83 to 0·75 over the above range of fractio

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1986.tb01797.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractThe effects of cutting frequency on dry matter yield, crop persistence and herbage quality of representative diploid and tetraploid varieties of broad red clover(Trifolium pratense)were investigated in two trials at Hurley in the period 1975–79.Pure‐sown swards of broad red clover varieties were used in the first trial (A), while both pure‐sown swards and those sown with a perennial ryegrass companion grass were included in the second trial (B).Tria1was cut three or six times per annum, trial B three, four or five times per annum. In both trials, the change from normal management of three cuts per annum to six (trial A) or five (trial B) cuts per annum reduced output, whether in terms of dry matter yield (trial A by 31%; trial B by 33%), N yield (trials A and B by 15%) or metabolizable energy (trial A by 24%; trial B by 28%), and in trial A also led to more rapid reduction in clover plant density. More frequent cutting also raised mean D–value (trial A by 5–3 units; trial B by 3–4 units) and N concentration (trial A by 64 g kg dry matter‐1; trial B by 70 g kg dry matter‐1). Tetraploid (4x) red clover varieties generally out–yielded diploid (2x) varieties, except in trial A in 1976 when, under drought conditions, Granta and Kuhn (both 2x) equalled the yield of Wensum (4x) and out–yielded Norseman and Maris Leda (both 4x).The companion grasses included in trial B formed a sequence from early to late flowering (Aberystwyth S24, Barlenna, Endura), and their inclusion raised dry matter yields and D‐value, though it lowered N concentration in the mixed herbage. Highest annual dry matter yields in this trial, which received supplementary irrigation, were 1641 ha‐1from a pure–sown crop (Hungaropoly) and 205 t ha‐1from a mixture (Wensum/ Aberystwyth S24), from three cuts in the first harvest year. Aberystwyth S24 had the greatest effect in raising yields; though least effect on improving digestibility. Endura was the converse, and it was concluded that an intermediate‐maturity variety such as Barlenna was the most satisfactory companion.Both trials A and B suggested that in south–east England, broad red clover can be considered only as a 2–year crop and that ways must be found to prolong its productive life. Strategies to increase the digestibility and hence the economic value of the crop by cutting more frequently than three times per year are unattractive because of the large fall in yield and relatively small improvement in digestibility and hence m

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1986.tb01798.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractSeeds of white clover (Trifolium repens) were sown alone or in fluid, or pre‐germinated in fluid on to the soil surface of slots cut in an oldAgrostis/Festucasward. Seeds were left uncovered or covered with a thin layer of soil and irrigated from the outset or after 14 days delay.With irrigation from the outset, seedlings established soonest from pre‐germinated seeds but final percentage establishment ranged only from 50 to 63% for the three states of seed. With delayed Irrigation, however, few pre‐germinated s1 survived and although germination of dry seed was delayed, final percentage establishment was unaffected. Soil covering increased establishment slightly. The number of leaves per seedling was greatest with pre‐germination and early irrigation and least with pre‐germination and delayed irrigation. Delayed irrigation also decreased the number of leaves per seedling for seedlings grown from dry seed.The effects of early irrigation persisted so that at 84 days it significantly increased total yield of clover from all three states of seed, on average threefold, but much more from pre‐germinated than from dry seed. Soil covering greatly increased yield, especially where irrigation had been applied from the outset. The interaction of early irrigation and soil covering was even more pronounced for stolon weights, and stolon growth of Individual seedlings appeared to benefit more from soil covering than from early irrigation.The results showed the importance of early seedling emergence, but no advantages of fluid sowingper se.They also indicated large overall beneficial effects of early irrigation and its additive interaction with so

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1986.tb01799.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractAt a site in Kent, perennial ryegrass (Lolium perenne) variety S24 and Italian ryegrass (L. multiflorum) variety RVP, wheat varieties Armada and Norman, and the original mixed grass ley were grown in small plots during 1982–84. Two toxic pesticides (phorate and aldicarb) were applied to half the total number of plots three times each year to eliminate soil invertebrate populations. Fertilizer was also applied to most plots. The yields of the crops, grown with and without pesticide, and the effects of the fertilizer were compared. Grass herbage yield was measured on three occasions during the summers of 1983 and 1984. Wheat grain yields were also determined in 1983.During the first year significant differences were not apparent in grass dry matter yield between pesticide‐treated and non‐treated plots, but significant differences were found in the second year. The perennial ryegrass was more susceptible to pest damage than the Italian ryegrass or the grass ley. Grass yields varied between cuts and in relation to variety and pesticide treatment, yields tending to be greater in untreated plots. Fertilizer treatment greatly increased grass dry matter yields, particularly with the Italian ryegrass. The effects of pesticide treatment on both wheat varieties varied although some yield enhancement was evident.Invertebrate animal populations in pesticide and fertilizer‐treated plots were also assessed in autumn 1982, spring and autumn 1983 and spring 1984. In contrast to pesticide treatment, fertilizer treatment had little effect on soil invertebrate populations. Nematode populations were reduced at each sampling occasion by the pesticide treatment. Slug populations were initially unaffected but were subsequently reduced. Leatherjackets, by far the most abundant pest in both grass and wheat plots, were markedly affected by pesticides on all sampling occasions. Generally, fewer soil‐dwelling dipterous larvae were recovered in spring than in autumn. Stem‐boring dipterous larvae were virtu

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1986.tb01800.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractThe effect of temperature on the spring growth of perennial ryegrass swards was studied at three contrasting sites. Two of these were situated on land restored after opencast coal mining, one of which had been drained. The third was on undisturbed land of the same soil type. Rates of leaf extension were measured in an attempt to give an early indication of differences in plant growth in the spring of 1982.Spring growth started earliest on undisturbed land. On the restored land drainage proved beneficial, for although the onset of growth was delayed compared to the undisturbed site the subsequent rates of growth were similar. Both the onset and the rate of growth were slower on the undrained site. Highly significant relationships existed between leaf extension rate and soil temperature at each site. However, when sites were compared, differences in soil temperature could only partly explain observed differences in growth rate between sites.It was concluded that some factor other than soil temperature was responsible for the difference in spring growth between the undisturbed site and the undrained opencast site in this experiment.

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1986.tb01801.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractAssessments were made of the clover yield and clover content between early June and late July 1984 of white clover in a permanent pasture which had been slot‐seeded in spring 1982.Past reserves of phosphate or application of propyzamide alone only slightly increased clover dry matter yield but together they increased it from 13 to 785 kg dry matter ha‐1and gave 31% clover in the total herbage yield. Applications of P2O5during the experiment, alone or together with past reserves of phosphate, Iased clover yield from 13 to 242 kg dry matter ha‐1and the proportion of clover from 1 to 10%. However, highest yields (1282 kg) and clover content (37%) were attained when P2O5and propyzamide were applied to treatments with past reserves of phosphate.These results confirmed the trends evident during the second year and also indicated a potential role for grass‐suppressants in increasing management options during the early years after slot

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1986.tb01802.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY