摘要:

SummaryThe liquid limits, degrees of dispersion, and moisture retention of a Tropical Red Earth consisting predominantly of kaolin and iron oxides were independent of the nature of the saturating cation. The same three properties of a Tropical Black Earth consisting predominantly of montmorillonite were dependent upon the nature of the saturating cation, with Na giving the highest values and K the lowest. Ca and Mg gave intermediate and essentially equal values.The effects of the four cations have generally been explained in terms of the balance between attractive and repulsive forces in soil solutions and pastes. Unexpected behaviour due to K saturation has been explained by specific adsorption of K in a manner similar to but weaker than irreversible fixation.Linear regression equations were derived to express the dependence of the three properties on the saturating cations. The regression equations, which were all highly significant, show that the four cations examined were acting independently. Small positive interactions between Na × K, Mg × K, and Ca × K indicated that the effect of K fixation was important only when the Black Earth was nearly saturated with K io

ISSN:0022-4588    

DOI:10.1111/j.1365-2389.1970.tb01167.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

SummaryStudies with32P on six soils showed that considerable re‐sorption of phosphate occurred during the Chang and Jackson fractionation procedure. This re‐sorption resulted in an underestimate of the NH4Cl‐extractable phosphate and an overestimate of‘occluded’ phosphate, with less consistent but significant changes in the other fractions. The corrections necessary to allow for re‐sorption varied be

ISSN:0022-4588    

DOI:10.1111/j.1365-2389.1970.tb01168.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY