摘要:

A plot experiment is described in which the direct effects of and the interactions between two of the main sources of nitrogen for grassland, namely clover and fertilizer nitrogen, were measured. The results demonstrated the value of both clover and fertilizer nitrogen in raising yields and showed that these two sources of nitrogen had a marked additive effect on yield in at least the first two years of the experiment. The practical implications of these results are discussed with reference to the results obtained on a field scale on the Institute's farm. Possible methods of combining the use of clover and fertilizer nitrogen within a fanning system are considered.

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1963.tb00319.x

出版商:Blackwell Publishing Ltd    

年代:1963

数据来源: WILEY

摘要:

The problem of combining clover and fertilizer nitrogen was studied in the presence and in the absence of the grazing animal. Results from mown experiments confirmed those of other workers and indicated that the large variation in response of a grass/white‐clover sward was related to level of clover production. Grazing, by recirculating nitrogen, raised the nitrogen status of all swards and increased the response to applied nitrogen. On grazed swards there was generally less clover than on mown swards, but grazing increased the nitrogen transfer from clover to grass. Grazed grass/white‐clover swards responded consistently to applied nitrogen and, at each nitrogen level (up to the 120 lb tested), out‐yielded the grass swards. A single spring nitrogen application to grass/white‐clover swards increased yield early in the season but on occasions reduced mid‐season production. A succession of applications—in early and late spring and summer—gave increased spring growth, stimulated yield in mid‐season and also accentuated the autumn flush. Applied nitrogen decreased clover population but did not impair the ability of the clover that remained to fix nitrogen and transfer it to associated grass. Practical suggestions for the use of clover and fertilizer nit

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1963.tb00320.x

出版商:Blackwell Publishing Ltd    

年代:1963

数据来源: WILEY

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1963.tb00321.x

出版商:Blackwell Publishing Ltd    

年代:1963

数据来源: WILEY

摘要:

The paper describes the use of fertilizers on grassland in England and Wales, as shown by surveys of fertilizer practice carried out during 1957–60.About a third of the total consumption of N and K and almost half the total consumption of P is on grassland. Fertilizer use on leys has increased rapidly in recent years and the overall average rate of application is now of the order of 0·3 cwt N, P2O5and K2O per acre per annum; permanent grass receives about half as much P and very much less N and K than the leys.Generally speaking, consumption of N and K per acre of grassland was higher in arable districts than in livestock‐farming areas, and on dairy farms than on rearing and feeding farms. However, rearing and feeding farms received more P per acre of grass (in particular, more basic slag) than arable farms. Little farmyard manure was used on grassland in the arable districts, whereas in the dairy counties of the western half of England and in Wales it formed a substantial part of the total plant nutrients supplied to grassland, particularly on fields mown for hay.The paper also gives information on types of fertilizers used and the timing of fertilizer applications to grassland. All but about a fifth of the nitrogen used on grassland was applied between February and A

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1963.tb00322.x

出版商:Blackwell Publishing Ltd    

年代:1963

数据来源: WILEY

摘要:

A rumen‐fistulated steer was used for the manual collection of samples of freshly swallowed herbage, in a grazing‐management experiment on a perennial ryegrass sward. Diurnal and seasonal changes in thein vitrodigestibility of the herbage selected by the grazing animal were studied under both strip‐ and continuous‐grazing methods of management.There was no appreciable change in digestibility as the sward was grazed down from upper to lower layers under strip‐grazing management in April and May. In June to October a within‐day fall in digestibility was found, much of which was attributable to an increase in the amount of old dead herbage grazed from the lower regions of the sward. Dead herbage taken in by the grazing steer was considerably lower in digestibility in August than in May. Thein vitrodigestibility of herbage samples, cut to ground level before and after grazing in a strip‐grazed treatment, fell markedly as the proportion of dead herbage in the sample increased, giving a high negative correlation.In a continuous‐grazing management there was no pattern of diurnal variation, and the seasonal variation in digestibility of the ingested herbage was less than in strip grazing. The implications of these results are discussed in relation to indirect methods of digestibility determination (faecal‐index technique), the measurement of herbage intake, and to some aspects of g

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1963.tb00323.x

出版商:Blackwell Publishing Ltd    

年代:1963

数据来源: WILEY

摘要:

Experiments to study the effect of pelleting and wafering on the feeding value of rations containing 50% or more roughage are reviewed. Although pelleting often depresses the dry‐matter digestibility of the ration, there appears to be no evidence of an alteration in the net energy value. The increased meat production and food‐conversion efficiency observed with pelleted rations is caused by an increased food intake. The extent of the improvement achieved by pelleting depends on the quality of the unpelleted ration. Milk production is sometimes changed by pelleting and milk‐fat percentage is depressed where finely‐ground hay has been used. Wafering does not appear to change the feeding value

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1963.tb00324.x

出版商:Blackwell Publishing Ltd    

年代:1963

数据来源: WILEY

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1963.tb00325.x

出版商:Blackwell Publishing Ltd    

年代:1963

数据来源: WILEY

摘要:

The effect of dalapon is described on pastures ofAgrostis/Festuca, Festuca ovinal Deschampsia flexuosaand relatedNardus‐ or Molinia‐rich hill grasslands. The results are discussed in relation to the technique of surface sowing and the choice of vegetation types suitable for treatm

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1963.tb00326.x

出版商:Blackwell Publishing Ltd    

年代:1963

数据来源: WILEY

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1963.tb00327.x

出版商:Blackwell Publishing Ltd    

年代:1963

数据来源: WILEY

摘要:

White‐clover herbage proved to be of relatively high digestibility and it was possible to predict the digestibility of mixed grass and clover herbages from a knowledge of the digestibility and proportions of the components. Lucerne proved to be of low digestibility. Aftermath herbage was not so highly digestible as first cuts; and in autumn digestibility falls slowly as herbage ages. Digestibility was unrelated to the nitrogen content of herbage. In three trials no significant differences were found between the digestive efficiencies of wether sheep and dairy cows, while hormone implantation, although affecting animal metabolism, failed to influence feed digestibility. Restricted feeding at 50% of thead libitumintake resulted in a slight increase in the apparent digestibility of herbag

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1963.tb00328.x

出版商:Blackwell Publishing Ltd    

年代:1963

数据来源: WILEY