Soil carbon fractions as indicators of sustainability of cotton cropping systems

Abstract

The cracking clay soils on which cotton is typically grown are prone to compaction, which can lead to a reduction in soil aeration, infiltration of water, and a condition where roots are unable to penetrate the dense layer of the soil. This in turn reduces yields and farm income, and in the longer term, will result in a reduction in soil quality and land value. Increasing public and grower concern about soil and environmental quality in relation to long-term sustainable cotton production has emphasised the need to develop and implement management strategies that maintain and protect soil resources. The development of sustainable cotton cropping systems requires the identification, monitoring and management of those soil properties whose variability significantly influence the stability and resilience of the soil resource. Since sustainability is a systems issue, the sustainability of a cropping system can be appropriately assessed through the use of indicators, which are partial indices that estimate some aspect of the broader concept. The selection of such indicators can be achieved through a step-wise approach; by identifying a set of attributes that constitute components of a sustainable cropping system, and then develop techniques for monitoring these attributes. The organic matter content of a soil is a key indicator of a sustainable cropping system because of its influence on the physical, chemical and biological health of a soil. Because organic matter in soil exists in a wide diversity of forms with considerable variability in decomposition rates, the success of any organic matter management strategy will depend to a large extent on methods that can detect and monitor short-term changes in soil organic matter quantity and quality.