Available water storage in a range of soils in north-eastern Queensland

Abstract

A comparative study of the available water storage capacity of three soils under Townsville stylograss vegetation is reported. Two of the soils were selected as representing solodized-solonetz and solodic soils typical of extensive areas of eastern Australia, yet differing greatly in their demonstrated productivity after fertilization. The third selection was a well-drained, highly productive soil. After fuli recharge, available soil water in the three soils above 1.5 m was 80, 150, 180f mm. Subsequent root density and soil water content profiles indicated that differences in water entry, and not in completeness of withdrawal, accounted for differences in storage. The difficulties of estimating the storage capacity of poorly drained soils is discussed. A technique is described which uses total porosity for estimation of the upper limit of the available water range and the distribution of total soluble salts as an indicator of the depth of water entry.