ISSN:1360-1261    

DOI:10.1111/j.1477-9552.1947.tb02182.x

出版商:Blackwell Publishing Ltd    

年代:1947

数据来源: WILEY

ISSN:1360-1261    

DOI:10.1111/j.1477-9552.1947.tb02183.x

出版商:Blackwell Publishing Ltd    

年代:1947

数据来源: WILEY

摘要:

Summary.Before the war, livestock production was responsible for the major part of the removals of N, P, K nutrients from British farms, but during the war (temporary ?) precedence in this respect was taken by direct human food crops. In both periods the feeding of home–grown crops to livestock was probably responsible for an annual rate of nutrient losses exceeding those due to removals from farms in crops and stock products combined.In addition to larger fertilizer inputs required for the expanded area of direct human food crops during the war, similar increases were essential for the attempt to sustain the pre–war cattle output, even with substantial reductions in the numbers of all other livestock. Nutrient materials for these purposes were not available during the war in quantity sufficient to allow. phosphate and potash applications to grassland in any appreciable degree; permanent grass, therefore, was the most likely to deteriorate in “fertility,” i.e. in potential productivity.So long as relatively unlimited supplies of imported feeding–stuffs are available at prices permitting their profitable processing into livestock products, they may largely compensate for the N, P, K losses incurred in the analogous conversion of home–grown crops and the nutritive quality of the latter fodders is not necessarily a consideration of prime importance. The war has demonstrated that British farming has still a long way to go before it approaches a self–sufficient livestock economy on the pre–war scale and should that be desirable in the future, it implies the production of foods of higher nutritive values.A post–war expansion of U.K. cattle and sheep production will demand the utmost economic exploitation of grass since it provides the cheapest mode of feeding. That implies a general improvement in past standards of management to secure from grass the maximum contribution to the total nutritive requirements of the stock, which in turn will, depend on increased throughputs of the major soil nutrients more commensurate with removals than has been th

ISSN:1360-1261    

DOI:10.1111/j.1477-9552.1947.tb02184.x

出版商:Blackwell Publishing Ltd    

年代:1947

数据来源: WILEY

ISSN:1360-1261    

DOI:10.1111/j.1477-9552.1947.tb02185.x

出版商:Blackwell Publishing Ltd    

年代:1947

数据来源: WILEY

ISSN:1360-1261    

DOI:10.1111/j.1477-9552.1947.tb02186.x

出版商:Blackwell Publishing Ltd    

年代:1947

数据来源: WILEY

ISSN:1360-1261    

DOI:10.1111/j.1477-9552.1947.tb02187.x

出版商:Blackwell Publishing Ltd    

年代:1947

数据来源: WILEY

ISSN:1360-1261    

DOI:10.1111/j.1477-9552.1947.tb02188.x

出版商:Blackwell Publishing Ltd    

年代:1947

数据来源: WILEY

ISSN:1360-1261    

DOI:10.1111/j.1477-9552.1947.tb02189.x

出版商:Blackwell Publishing Ltd    

年代:1947

数据来源: WILEY

ISSN:1360-1261    

DOI:10.1111/j.1477-9552.1947.tb02190.x

出版商:Blackwell Publishing Ltd    

年代:1947

数据来源: WILEY

ISSN:1360-1261    

DOI:10.1111/j.1477-9552.1947.tb02191.x

出版商:Blackwell Publishing Ltd    

年代:1947

数据来源: WILEY