Soil organic carbon storage in four irrigated cotton cropping systems sown on permanent beds in a cracking clay with subsoil sodicity was determined over a 9-year period in a trial near Narrabri, NSW.

salinity, and low exchangeable K concentrations are common constraints in many cracking clays. Recommendations for ameliorating sodicity include applying gypsum alone or in combination with deep tillage.

Long-term studies of soil organic carbon dynamics in irrigated cotton -based cropping systems under varying stubble management practices in cracking clays are relatively few.

Sustainability in any farming system is dependent upon a number of interacting factors which include climate, soil quality, plant nutrition, management, weed and disease incidence, and economic factors.