Soil fertility changes in the long-term experimental plots at Kybybolite, South Australia. IV. Changes in certain moisture characteristics

Abstract

A study of soils from various pasture treatments at Kybybolite has shown that changes in soil moisture characteristics have occurred in association with increases in organic matter. The 15 atmospheres (atm), 0.33 atm, and available water capacity (A.W.C.) values have all shown increases which can be related to organic matter changes. The largest increase has occurred in soil moisture-holding capacity (0.33 atm). Less than half of this increase, however, is available for plant growth, owing to corresponding increases in 15 atm values. Calculations of A.W.C. in terms of depth of soil water has shown that the magnitude of the change has been relatively small in relation to the large increases in organic matter. The results indicate that the scope for substantially increasing A.W.C. in coarse-textured soils by pasture improvement is limited. Possible beneficial and deleterious effects on plant growth due to observed changes in moisture characteristics of the surface soil are discussed.