ISSN:0022-4588    

DOI:10.1111/j.1365-2389.1954.tb02170.x

出版商:Blackwell Publishing Ltd    

年代:1954

数据来源: WILEY

ISSN:0022-4588    

DOI:10.1111/j.1365-2389.1954.tb02171.x

出版商:Blackwell Publishing Ltd    

年代:1954

数据来源: WILEY

ISSN:0022-4588    

DOI:10.1111/j.1365-2389.1954.tb02172.x

出版商:Blackwell Publishing Ltd    

年代:1954

数据来源: WILEY

ISSN:0022-4588    

DOI:10.1111/j.1365-2389.1954.tb02173.x

出版商:Blackwell Publishing Ltd    

年代:1954

数据来源: WILEY

ISSN:0022-4588    

DOI:10.1111/j.1365-2389.1954.tb02174.x

出版商:Blackwell Publishing Ltd    

年代:1954

数据来源: WILEY

ISSN:0022-4588    

DOI:10.1111/j.1365-2389.1954.tb02175.x

出版商:Blackwell Publishing Ltd    

年代:1954

数据来源: WILEY

摘要:

SummaryAfter defining the sense in which the term soil structure is used in the paper, the various methods for studying it are discussed, followed by a brief survey of recent literature. Descriptions are then given of adaptations of various methods which have been found suitable for studying structural changes in soils in long‐term rotation experiments under the climatic conditions of Britain. As an indica‐tion of the usefulness of the methods, some results typical of those obtained in the field and laboratory are gi

ISSN:0022-4588    

DOI:10.1111/j.1365-2389.1954.tb02176.x

出版商:Blackwell Publishing Ltd    

年代:1954

数据来源: WILEY

ISSN:0022-4588    

DOI:10.1111/j.1365-2389.1954.tb02177.x

出版商:Blackwell Publishing Ltd    

年代:1954

数据来源: WILEY

摘要:

AbstractThe isotopic exchange of phosphorus has been studied between solutions of orthophosphate and the following solid phases: anion‐exchange resin charged with phosphate; dicalcium phosphate; rock phosphates; hydroxyapatite aged to varying extents; and natural soils.The nature of exchange reactions in the soil is discussed. It is considered that all inorganic phosphate fractions in the soil undergo exchange with added phosphates, though at different rates.Consideration is given to procedures proposed by earlier workers for the estimation of the phosphate status of the soil by tracer methods. In particular, the hypothesis that‘plant available’soil phosphate can be estimated by comparing the specific activity of phosphate added to the soil with that of phosphate absorbed by plants is examined. It is shown that the method is of limited application. It appears, however, that since‘plant‐available’soil phosphate undergoes isotopic exchange more readily than‘unavailable’forms, it should be possible to estimate available soil phosphate by observing isotopic exchange between solutions and soil suspensions under controlled conditions. The appropriate procedure will vary between soil types and must be determined byad hocinvestigations.The limitations which isotopic exchange and isotopic dilution effects impose on the estimation of fertilizer absorption by tracer method

ISSN:0022-4588    

DOI:10.1111/j.1365-2389.1954.tb02178.x

出版商:Blackwell Publishing Ltd    

年代:1954

数据来源: WILEY

ISSN:0022-4588    

DOI:10.1111/j.1365-2389.1954.tb02179.x

出版商:Blackwell Publishing Ltd    

年代:1954

数据来源: WILEY