摘要:

SummarySoil organic matter was extracted by a mixture of O.IM Na4P2O: O.IM NaOH from a chronosequence of weakly weathered soils developed on aeolian sand, and fractionated into humin (non‐extractable), humic acid, and fulvic acid. The mass of total organic carbon in the profiles, the14C content and the13C/12C ratios were also determined.The weight of total carbon increased rapidly at first and then gradually without attaining a steady state. This trend was also shown by the humin and fulvic acid fractions, but the humic acid fraction appeared to have reached a maximum after about 3000 years. The order of total weights of the organic fractions was humin>fulvic acid>humic acid.The evidence suggests that the proportions of the humic fractions formed by decomposition are related to soil differences but not to vegetation. The greater part of the plant material found in the soils appears in the humin and fulvic acid fraction

ISSN:0022-4588    

DOI:10.1111/j.1365-2389.1976.tb01979.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

SummaryThe best procedure for mapping the soils of an area, and the effort this will require, depend upon the intricacy of its soil pattern.This paper presents one way of describing such intricacy‐by a graph of variance against area sampled‐and anexploratoryattempt to determine its form for OM, N, coarse and fine sand, silt, clay, gravel, available P and K, CEC, exch. Ca, Mg and K, in areas in the Northern Territory of Australia. This confirmed that there are considerable differences between the graphs for different properties and that areas differ very much in the short‐ and long‐range contributions to the total variability of their soil. It demonstrated the inevitable sampling problems in determining the form of variance‐ar

ISSN:0022-4588    

DOI:10.1111/j.1365-2389.1976.tb01980.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

SummaryThe effects of the migration of two soil constituents into illuvial horizons is described by a set of equations. Differential movement of clay fractions during illuviation causes changes in the fine to total clay ratios in A and B horizons.A mathematical model is used for the interpretation of clay fraction data in order to estimate the degree of profile development, the amounts of fine and total clay which have moved, and to determine the original composition of the parent material. No bulk density data of the soil horizons are necessary for the computation.The equations can be programmed on desk calculators. Comparison with measurements on Alfisols in temperate regions was found to be satisfactory.

ISSN:0022-4588    

DOI:10.1111/j.1365-2389.1976.tb01981.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY