摘要:

AbstractThe experiment was undertaken to examine the interactions between yield responses to secondary applications of fertilizer N and length of regrowth interval following three levels of primary N. A sward of S24 perennial ryegrass received all combinations of three fertilizer treatments, nil, 50, and 100 kg ha‐1N for primary growth harvested on 21 May and four treatments, nil, 33, 66 and 100 kg ha‐1N for the second growth harvested 2, 3, 4, 5, 6 or 7 weeks later.Cubic equations of growth were derived from the yields of dry matter and both the direct response to secondary N and the residual responses to primary N increased as regrowths developed. A positive residual effect to increasing primary N was obtained at the three lower levels of secondary N for weeks 4–7 but a negative response was obtained with the highest level of secondary N. The implications are discussed in terms of target responses and yields and the growth interval required to attain these ta

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1981.tb01532.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

AbstractAn experiment examining the relationship of daily herbage disappearance (DHD) and daily herbage allowance (DHA) is described. Cows with calves were grazed at three stocking rates on Kleingrass and Coastal Bermudagrass pastures. DHD and DHA were monitored at 14‐d intervals. A significant positive linear relationship was noted between DHD and DHA (P0·25). Equations derived for Coastal Bermudagrass and Kleingrass were not significantly different and resulted in a combined equation Ŷ= 0·275X + 0·209 with anr2vaiue of 0·27. As DHA exceeded 6–9 kg DM per 100 kg live weight, efficiency of defoliation by the cows and calves

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1981.tb01533.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

AbstractThe water loss from tall fescue cv. S170, perennial ryegrass cv. S24, Italian ryegrass cv. RvP and timothy cv. S352 when dried as a thin layer under controlled conditions at 20°C and r.h. 50% is described. Comparisons were made on six occasions between mid‐April and mid‐June. Tall fescue dried faster than the other species and the time to reach a water concentration of 0·2 g water per g dry matter varied little between the six harvests. In contrast, the drying time for the ryegrasses and timothy increased to maximal values in mid‐May and then fell. Drying time was dependent on the initial water concentration of the grass, the ratio of leaf to stem and on the amount of true stem exposed to the drying environment. The practical implications in relation to haymaking are di

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1981.tb01534.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

AbstractThe mineral composition ofLolium perenne, Dactylis glomerata, Trifolium repens, Lotus corniculatusand six non‐leguminous broadleaved herbs was determined at two sites on copper‐deficient soils with and without soil‐applied copper sulphate at 2 kg Cu ha‐1.D. glomeratawas richer thanLolium perennein P, Mn and Cu, andT. repenswas richer than either grass species in Ca, P, Mg and Cu.D. glomeratacultivars differed in Ca, P, Na and Mg concentrations, andL. perennecultivars in Ca concentration.Lotus corniculatuscontained less Ca, P, Na and Mn but more Zn thanT. repens. Achillea millefoliumwas rich in K,Cichorium intybusin K, Mg and Zn,Petroselinum crispumin Na and Zn,Rumex acetosain K, P, Mg and Zn andTaraxacum officinalein Na, Mg and Zn.Rumexwas low in Na andPlantago lanceolatain Na and Mn. None of these herbs was richer thanT. repensin Cu. Copper sulphate application raised the Cu concentration of the herbage only slightly, species or varieties differing little in their response to applied Cu. It is concluded that adjustment of botanical composition, with or without copper sulphate application, will not help to prevent hypocupraemia in grazin

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1981.tb01535.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

AbstractFour grass silages of two chop lengths and two D‐values were made from S23 perennial ryegrass, and compared in a feeding experiment with lactating cows and in an eating‐behaviour study with non‐lactating cows. The median chop lengths were 11·6 and 11·5 mm in the short silages and 18·2 and 19·5 mm in the medium silages. Chop length had negligible effects on D‐value and on pH with values of 3·81 and 3·94 on the short and medium silages respectively.Silage DM intakes were higher on the short than on the medium‐chop silages in both experiments except where the high D‐value silage was supplemented with concentrates. Milk yields were not affected significantly by chop length with daily values of 19·3 and 19·7 kg per cow on the short and medium treatments respectively with the high D‐value silage, and 18·2 and 18·3 kg per cow with the low D‐value silage. Chop length had only small and non‐significant effects on milk composition.Eating times expressed as min per kg DM were significantly lower on the short than on the medium‐chop silages.It is concluded that the small differences between the short‐ and the medium‐chop silag

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1981.tb01536.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

AbstractTwo experiments are described in which groups of lactating cows, non‐lactating cattle and weaned calves grazed a sequence of swards varying in maturity and herbage mass under strip grazing management at a daily herbage allowance of 60 g dry matter per kg live weight. Lactating cows ate 43% and 76% more herbage than non‐lactating cattle of similar weight in the two experiments but herbage OM intakes per unit live weight by the calves and lactating cows were similar.Variations in diet digestibility and herbage intake in the lactating and non‐lactating cattle with changes in sward conditions were similar. In the first experiment the calves were experienced grazers; the variation in the digestibility of the herbage selected was less in the calves than the adult cattle, but the variation in herbage intake was greater. The calves in the second experiment were younger, and they were inexperienced grazers; their ability to increase herbage intake in response to changing sward conditions was poorer than that of adult cattle, though variations in diet digestibility were similar in all classes.The practical implications of these results are discussed br

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1981.tb01537.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

AbstractThe results are reported of an examination of detailed measurements on the ingestive behaviour of calves and lambs in response to variations in the surface characteristics of swards under strip‐grazing and continuous stocking managements. It is shown that intake per bite and the short‐term rate of herbage intake were both sensitive to the height of the surface horizon above ground level but, at least under strip‐grazing management, not to variations in herbage density in the grazed horizon. The rate of biting was less sensitive to variations in sward conditions, particularly under strip‐grazing.Both intake per bite and rate of intake were more sensitive to variations in grazing height under strip‐grazing, where sward changes were rapid, than under continuous stocking, where they were slow. Under continuous stocking, ingestive behaviour was more sensitive to changes in sward conditions in lambs than

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1981.tb01538.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

AbstractThe effects of five herbicides on seed yield and viability of perennial ryegrass cv. S24 were tested at two sites. Benzoylprop‐ethyl, chlorfenpropmethyl, difenzoquat, ethofumesate and flam‐prop‐isopropyl were safe to use at doses recommended for use in other crops. When applied at three times the recommended dose, only difenzoquat reduced the yield and germination of seed and benzoylprop‐ethyl reduced seed germination. The recommended doses of difenzoquat and ethofumesate were safe when applied on cv. Barlenna at different growth stages. Difenzoquat reduced seed yield only after three times the recommended dose was applied to tillered plants. Ethofumesate, even at three times the recommended dose, did not affect seed yield but plant numbers were reduced by early treatment. The results suggest that the herbicides tested may be safe to use in perennial ryegrass seed crops at the recommended doses but more work is needed on the safety of difenzoquat in relation to crop growt

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1981.tb01539.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

AbstractThe practise of sward desiccation using glyphosate or paraquat followed by direct drilling of seed gave an environment which increasingly inhibited germination and establishment when the interval between spraying and drilling was decreased from 21 days to nil. Burning or removal of old sward improved establishment. Calcium peroxide used as a seed dressing improved seedling establishment in most treatments.

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1981.tb01540.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

Book review in this articleTropical Pastures and FodderCrops By L. R. HumphreysThe Role of Nitrogen in Intensive Grassland ProductionEdited by W. H. Prins and G. H. Arnold.Agricultural Botany, 1. Dicotyledonous Crops, 2. Monocotyledonous Crops, By N. T. Gill and K. C. Vear, Third edition revised by K. C. Vear and D. J. Barnard

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1981.tb01541.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY