摘要:

ABSTRACTTillering is examined in relation to the morphology and habit of growth of the perennial herbage grasses; particular reference is made to the effects of cutting and grazing. The importance of tillering in establishment and regeneration or perennation of a grass sward is considered; greater importance is attached to the role of tillers in the regrowth of swards cut for conservation at the reproductive stage of growth. Amounts of regrowth are related to both the number and size of vegetative tillers present at the base of reproductive tillers at the time of cutting. The probable inhibition of the replacement tiller buds by the developing inflorescence is suggested as a reason for the poor growth of grass swards in the favourable environment of midsummer.The physiological mechanisms which control tillering during reproductive development are examined. Spring and winter wheat (Triticum aestivum), Lolium temulentumandPhalaris tuberosaare used as physiological tools to demonstrate that tillering is restricted during reproductive development, and that stem extension may be more important than changes at the stem apex in controlling this restriction of tillering at the base of the inflorescence‐bearing stem. It appears from results of the application of a range of growth regulators that substances derived from the meri‐stematic centres, in either the elongating stem or the terminal meristem, indirectly control the metabolic activity of the lateral buds from which new tillers are derived. The degree of apical dominance is shown to depend on the light intensity in which the plants are grown. Finally, the physiological results are used to suggest reasons for the commonly found apparent inability of heavily fertilized perennial ryegrass (Lolium perenne) swards to regrow after cutting at the inflorescence‐emergence stage of g

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1972.tb00689.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

ABSTRACTThe capacitance meters available in the past for estimating herbage yields have lacked sensitivity at the extremes of their range of measurement. The preliminary evaluation of a highly sensitive capacitance meter described here indicates that accurate measurement is possible in the range 0.1100 kg DM/ha. The implications of this development for the measurement of herbage of low availability are discussed.

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1972.tb00690.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

ABSTRACTA study of the relationship between some farm and grassland management factors and milk production at the Hannah Dairy Research Institute in the period 1951–70 is reported. During this period various aspects of farm management were altered, and total annual milk production was increased from 28,400 to 63,900 gal. The major factors influencing total milk production, in order of declining importance, were: the overall rate of stocking, milk yield per cow, the numher of milking cows as a percentage of all animals, and the acreage of grass as a percentage of the total farm acreage. Stocking rate and milk yield per cow together explained 85% of the total variation in annual milk production. No significant relationship was found between total milk production and weight of concentrates fed/gal, the amount of fertilizer N applied/aC, rainfall and sunshine data. It is suggested that the lack of a direct relationship between milk prodnction and the amount of fertilizer N applied resulted from the contribution of N from clover and from grazing animal

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1972.tb00691.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

ABSTRACTWays of using nitrogen fertilizer and long growth periods to produce grass for summer milk production are described. To exploit the extra production obtained from long growth periods it is suggested that the grazing system should be flexible, integrating cutting with grazing.

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1972.tb00692.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

ABSTRACTThe loss of water from small bulk samples of five grass species was studied under constant conditions of humidity, temperature and lighting. A logarithmic curve was fitted to the data and the different species compared on the basis of a loss coefficient derived from the fitted curve. The species varied significantly in this aspect; those with high surface‐area to dry‐weight ratios generally lost water fastest The presence of stem material appeared to increase the rate of water loss considerably. High humidity during drying caused the grasses to lose water more slowly and to retain much more water at equilibrium with the surrounding air. Chemical treatments to speed water loss, using a solvent and a fungal toxin were tested. Both appear to have some promise. Selection for high water loss in grass breeding may also be possi

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1972.tb00693.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

ABSTRACTWinter (vernalized) and summer (non‐vernalized) timothy tillers were grown to anthesis in day/night temperature regimes of 32/26°, 27/21°, 21/15°, and 15/10°C. Herbage and total plant yields, total leaf‐blade number and area, and total plant growth‐rate were highest, or very nearly so, in the 21/15°C regime for both the winter and summer plants. However, summer plants reached anthesis 13 to 14 days later than winter plants in each temperature regime. Even though virtually all primary shoots produced an infiorescence, summer plants had significantiy more leaves and leaf‐blade area, produced significantiy higher yields of leaf blade, stem plus sheath, stubble, and root tissues and had a significantly higher total plant growth rate than winter plants in each temper

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1972.tb00694.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

ABSTRACTFive substrates (high‐quality brome grass, low‐quality brome grass, lucerne pellets, lucerne cubes, and barley straw) were analyzed for DM disappearance in a two‐stagein vitrosystem in nine consecutive runs. Samples for each run were inoculated in duplicate with four independent collections of rumen fluid from the same mature, non‐lactating Holstein cow. Data repeatability was excellent for the two lucerne substrates, good for high‐quality brome grass, and poor for low‐quality brome grass and b

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1972.tb00695.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

ABSTRACTEighteen crossbred Aberdeen‐Angus and six Shorthorn steers with an average liveweight of 382 kg were given silage (DM content 22.3%)ad lib., supplemented with 0, 1.2, 2.4 and 3.6 kg artificially dried grass, or 1.8 kg rolled barley, per day. A digestibility study carried out on the silage and dried grass showed that the concentration of the metabolizable energy was 52.7 and 45.6 kcal/100 kcal of food, respectively. Live‐weight gain increased with each level of supplementation. Supplementation did not significantly affect the intake of silage DM, but differences in the intake of total DM were significant. The killing‐out percentages of the steers were similar. The results suggest that dried grass pellets may be a usefid supplement for a silage diet. It was shown that 1.12 kg of dried grass was equivalent to 1.80 kg rolled barley as a supplement for s

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1972.tb00696.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

ABSTRACTFifteen out of 36 possible combinations of 3 cutting dates for hay, 3 rates of N application and 4 intervals between N application and cutting date were compared to study the effects of pre‐harvest application of N on the N, P, K, Mg and Ca contents of the aftermath and the effectiveness of utilization of these elements.According to the method of calculation given by ARC (1), the control haycrop harvested on 16 June was deficient in N, Ca, P and Mg, and the aftermath which was given no further N after harvest was of low bulk, but adequate in mineral content. Earlier harvesting improved the quality of the hay, and increased the bulk and reduced the mineral content of the aftermaths. Applying 125.6 kg N/ha after harvest resulted in a satisfactory increase in bulk, plus an improved mineral content in the aftermath. Applying N before harvest resulted in increased uptake of N, K, Ca, P and Mg in the hay and in the increased percentage of N, K, and Ca in the DM of the hay. Very early application of pre‐harvest N increased the percentage of Mg.The general effect of pre‐harvest N on the aftermath was to reduce yield and uptake of N, K, Ca, P and Mg. Doubling the pre‐harvest N raised the mineral uptake. Very early pre‐harvest application resulted in low mineral uptake in the aftermath. The percentage of N, K and P in the aftermath was reduced by pre‐harvest N applied at both levels and on both dates.Deferring the application of fertilizer N until 4 days after harvesting the hay crop produced the highest mineral contents in the aftermath, without reducing its bulk.Mineral uptake in the regrowths was linearly related to N uptake at 1.43 kg K, 0.34 kg Ca, 0.157 kg P, 0.006 kg Mg/

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1972.tb00697.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

Books review in this article:ROTHAMSTED EXPERIMENTAL STATION.Details of the classical and long‐term experiments up to 1967NIX, J.Farm management pocketbook. Ed. 4WIESNER, C. J.Climate, irrigation and agricultureHARBORNE, J. B.; BOULTER, D.; TURNER, B. L. (Editors)Chemotaxonomy of the LeguminosaeNELSON, J. G.; CHAMBERS, M. J.; CHAMBERS, R. E. (Editors)Process and method in Canadian geograp

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1972.tb00698.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY