A review of physical management for crusting control in Australian cropping systems - Research opportunities

Abstract

Soil surface crusting has severe agricultural and environmental effects. In Australian cropping areas, many studies have dealt with chemical treatments (as reviewed by Chartres 1992) but less emphasis has been focussed on physical management practices. The present review deals initially with 30 papers which involve reduced tillage, stubble retention and seedbed formation. Conservation practices have usually been analysed by their effects on soil properties, soil erosion and crop yield rather than by their specific impact on crust development. Moreover, the effects of reduced tillage and stubble retention on crusting have not been determined in most studies. Seedbed formation (e.g. the Tatura system), however, has been shown to be an effective physical management practice for crusting control. Many stability tests have been developed in Australia and used worldwide. Choice of the most relevant predictive test, as well as selection of the most suitable control technique, actually requires a good knowledge of the processes which can be involved in crust formation according to the soil, climatic and management conditions. The results of this review, which deals with 95 papers, suggest a few research opportunities, i.e. (i) furthering of knowledge about the different processes involved in crust formation under various cropping environments, (ii) monitoring soil strength according to crust development, (iii) development of field methods for the assessment of crust development, (iv) development of quantitative models consistent with recent qualitative crusting models, (v) development of methods for the determination of crust development at the field scale rather than small plot scale. Finally, this review recommends to integrate soil surface crusting studies and soil erosion studies.