ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1962.tb00264.x

出版商:Blackwell Publishing Ltd    

年代:1962

数据来源: WILEY

摘要:

An investigation into the effect of different environments on lucerne varieties seeded in southern latitudes was carried out at Cambridge on spaced‐plants and on yield trials during 1954–60. The varieties Flandria (northern French), Provence (southern French), and Grimm (Canadian) were multiplied in Cyprus for two generations under the control of the Department of Agriculture there. The English variety Eynsford was multiplied in countries of the Mediterranean area for one generation under the supervision of the O.E.E.C. and F.A.O.Morphological and physiological changes took place in Flandria. Eynsford and Grimm, the significance of which in relation to the generation, the authenticity of variety and the yield of fodder are discus

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1962.tb00265.x

出版商:Blackwell Publishing Ltd    

年代:1962

数据来源: WILEY

摘要:

The yield and phosphorus uptake of grasses and clovers from Welsh soils were studied in 6‐inch flower pots. Attempts were made to relate the phosphorus that the plants had been able to absorb to various measurements of the labile phosphorus in the soil. It is shown that in these‘phosphate fixing’ soils, absorption is not related to the exchangeable phosphorus as measured by equilibration. The values obtained for the latter are very high compared with the small amounts of phosphorus that the plants have been able to absorb, giving support to the view that the conversion of phosphorus to insoluble forms is not the main feature of‘fixation’ in these soils. Absorption of phosphorus by the grass was, however, related to the Larsen (L) values. In previously unfertilized soils, the fact that the L values were also related to the acetic‐soluble phosphorus content confirmed the belief that acetic extraction is a suitable means for assessing the abilities of such soils to provide the necessary phosphorus for plant growth. In soils containing reserves of residual phosphorus, however, much of the phosphorus that contributed to the L values was not extracted by acetic acid, and this method of extraction is unsuitable for use with such soils. Placement of the applied phosphorus near the root zone led to a decrease

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1962.tb00266.x

出版商:Blackwell Publishing Ltd    

年代:1962

数据来源: WILEY

摘要:

Many studies in recent years have stressed that grassland provides the greater part of the feed requirements of ruminant livestock in temperate lands, that a large proportion of this is supplied as grazing (83, 122) and that in this form it is the cheapest source of feed for ruminants (25, 38, 40). Several authors have contrasted the production estimated to be available from pasture with the much lower proportion—about 50% (74, 116)—harvested by the animal. For these reasons the efficiency of grass utilization under grazing conditions has received intensive study in the past 20 years and many of the principles of grazing management have been elucidated. Consideration of grazing management involves a study of the needs of the animals to be catered for, the sequence of grass crops which may be grown over the season, including the influence of special‐purpose pastures and of fertilizer treatment on the yield and seasonal distribution of production, and the effective conservation of surplus herbage. In this review, however, attention is concentrated on the problems concerned in grazing management for the dairy cow during the main growing period of the year. The object of grazing management may be defined as ‘to ensure a large supply of nutritious grazing over the growing season at a low cost and to utilize it in such a manner that physical waste of herbage and inefficient utilization by the animal are minimized and the productive capacity of the sward is maintained’. It is a complex subject, involving many interrelated factors including botanical, animal and per‐acre considerations. These are briefly outlined before the available experimental data in grazing management practices are

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1962.tb00267.x

出版商:Blackwell Publishing Ltd    

年代:1962

数据来源: WILEY

摘要:

Over a period of 20 months twenty continuous, 24‐hour, observations were made on the grazing behaviour of Border Leicester × Merino sheep. Distinct seasonal changes were found in the pattern of grazing. Grazing usually began during the dawn period and decreased at dusk. In spring and summer there were two peaks of grazing, but there was only one peak in autumn and winter. The percentage of grazing taking place between 6 a.m. and 6 p.m. varied with season, and was highest in spring and early summer. These seasonal changes in the pattern of grazing appeared to be independent of grazing pressure, or of the nutritional requirements of the sheep.The mean grazing time, for all observations, was 8·2 hours with a standard deviation of 0·97. Decreasing pasture availability increased grazing time, as shown by an increased intensity of grazing.Ruminating times were found to be considerably lower than have been reported for cattle. There was a significant negative correlation between ruminating time and the nitrogen content of available pasture.There was no clear evidence that the number of lambs carried before parturition, or suckled after parturition, had any effect on grazing time.There was no evidence that the behaviour of one sheep influenced that of another, even of a twin, grazing nearby.Consistent differences between sheep were found for ruminating time. The variation in grazing time between sheep, at any one time, was considerably greater than previously reported and differences between sheep were not consistent.Variation in grazing time appeared to be less in flocks of less than 6 sheep than in flocks of 6 to 12 s

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1962.tb00268.x

出版商:Blackwell Publishing Ltd    

年代:1962

数据来源: WILEY

摘要:

The effect of stocking density on the productivity of yearling female sheep was studied over the 1960 grazing season. The cumulative effect on pasture productivity of previous differences in grazing pressure was eliminated by re‐randomization of the pasture after each grazing cycle. Stocking densities from 12 to 30 sheep/acre/unit of time were imposed from March to September, followed by 7 months on a common treatment to measure subsequent effects on animal fertility. Correlations were found between stocking density and (a) liveweight gains, (b) loss of weight in fasting, (c) quality and quantity of herbage residues at the end of the last grazing cycle. Subsequent animal fertility was not measurably affecte

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1962.tb00269.x

出版商:Blackwell Publishing Ltd    

年代:1962

数据来源: WILEY

摘要:

It has been shown that hops can be grown satisfactorily in grass swards, but the practice cannot be generally recommended to commercial growers. Where irrigation is given, however, grassing‐down has some complementary advantages. Vigorous swards of clover have been maintained for several years, notwithstanding heavy applications of mineral nitrogen. With close mowing and generous manuring,Poa annuaeventually becomes completely dominant and can be regarded as the characteristic grass of hop gardens and orchards which are given these two treatments. The results suggest that a closely‐mown cover of herbage between crops may have advantages in countries where soil erosion is more severe than in Brit

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1962.tb00270.x

出版商:Blackwell Publishing Ltd    

年代:1962

数据来源: WILEY

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1962.tb00271.x

出版商:Blackwell Publishing Ltd    

年代:1962

数据来源: WILEY

摘要:

A study was made of the agronomic behaviour of 18 grass varieties, surface sown, after burning an upland heath community dominated byCalluna vulgaris. Complete exposure of the soil surface, the absence of competition and favourable moisture conditions provided excellent conditions for establishment. Despite this, sward development was slower than at any other site studied, and 18 months elapsed before satisfactory sward densities, and consequently a reasonable level of production, were achieved. In contrast, white clover developed vigorously from the outset. The red fescues, cocksfoots and S170 were the most promising, while the performance of most varieties was affected by one or more hazards such as frost‐heaving and summer drought. The latter aggravated the tendency of some of the varieties to produce a profusion of flowering stems and, with few exceptions, considerably reduced the colour and vigour of the herbag

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1962.tb00272.x

出版商:Blackwell Publishing Ltd    

年代:1962

数据来源: WILEY

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1962.tb00273.x

出版商:Blackwell Publishing Ltd    

年代:1962

数据来源: WILEY