Preliminary findings - Effect of alternative cropping management on soil organic carbon

Abstract

One of the alternatives to conventional (Conv) farming system is organic (Org) farming to prevent or to mitigate negative environmental impacts of intensive agriculture. Organic farming systems are claimed to be more resilient to weather extremes and can outperform conventional systems in weather extremes such as floods and droughts due higher levels of soil organic carbon (SOC).Whether organic or conventional, crop residue management (RM) plays an important role in maintaining SOC in horticulture, especially where annual crop rotations rely on frequent tillage. Stubble retention, incorporation and burning are the main three stubbles management practices in Australia. The effects of tillage and RM are often complex and difficult to separate. Theoretically, the effects of the two practices on SOC dynamics differ and can be opposing: no-tillage reduces the rate of organic carbon breakdown and potentially can reduce soil carbon losses, while stubble retention/burning directly affects the rate of organic input. The argument that organic farming is better than conventional farming for SOC storage have been challenged by critics due to its high reliance on cultivation (tillage) for weed control although its fertility management requires the addition of high levels of organic materials.