Relationships between soil morphology and soil properties relevant to irrigated and dryland agriculture

Abstract

A number of morphological attributes are commonly assumed to serve as surrogates for properties that cannot be practically measured on a routine basis This study investigates whether conventional soil morphology can be used for predicting soil properties of relevance to irrigated and dryland agriculture in the lower Macquarie Valley, N S W Measurements from 224 profiles were used to develop regression equations with morphological properties as explanatory variables Response variables included gravimetric moisture contents at -10 and -1500 kPa, available water capacity, ail-filled porosity, ESP, dispersion index, the coefficient of linear extensibility, bulk density and CEC The relationships between field texture and particle size classes were also determined Conventional sod morphology provided only moderate predictions of the agronomically more important properties In the lower Macquarie Valley, texture and colour were the most useful explanatory variables Most of the remaining morphological properties, and in particular conventional descriptors of structure, contributed little to improving prediction Options for more cost-effective and direct measurements, especially of profile macrostructure are considered.