A TECHNIQUE FOR INTERPRETING THE MACROSCOPIC AND MICROSCOPIC STRUCTURE OF SOIL

A method of interpreting data on the macroaggregate or microaggregate state of soil from the results of pairs of different structural analys es (dry and wet screening, microaggregate and particle-size analysis) is proposed. The raw data are used to calculate several indices: the w eighted-mean diameters and the particle-size distribution entropies fo r two paired types of analysis, and the relative discrepancies of the particle-size distributions obtained by the two types of analysis. The discrepancies are expressed by the weighted-mean diameters of aggrega tes broken up by the more drastic of the two treatments, the abundance of the particles formed by the breakdown of these aggregates, the abu ndance of ''stable'' aggregates, the entropy of the particle-size dist ribution, and a structural instability index for each of the paired ty pes of treatment. A new index of the soil water resistance of soil mac rostructure is proposed.