Managing yield decline in sugarcane cropping systems

Abstract

This paper summarises the results from ten years of yield decline research carried out by the Sugar Yield Decline Joint Venture in the Australian sugar industry. The research concludes that, although the ultimate expression of yield decline may be through adverse effects of pathogens on sugarcane root systems, yield decline is a complex issue caused by a number of factors being out of balance in the sugarcane cropping system. Soil degradation has been the result of the long-term sugarcane monoculture and how it has been practiced. Specific research has shown that the long-term monoculture, uncontrolled traffic from heavy machinery and excessive tillage along with practices that deplete organic matter all contribute to yield decline. It is argued that changes to the cropping system that will conserve organic matter, break the monoculture, control traffic and minimize tillage are the most appropriate ways to combat yield decline. The technology is now available to incorporate these changes into the cropping system and a more sustainable, profitable and environmentally responsible cropping system is proposed. The proposed system is not prescriptive and many acceptable variations will be just as suitable providing the basic principles of organic matter conservation, breaking the monoculture, controlling traffic and minimizing tillage are no compromised.