The impact of farming systems on soil biology and soilborne diseases: Examples from the Australian sugar and vegetable industries the case for better integration of sugarcane and vegetable production and implications for future research

Abstract

A sugarcane farming system based on residue retention, minimum tillage, a leguminous rotation crop and controlled traffic using global positioning system guidance is currently being adopted by the Australian sugar industry because it improves sugar yields, reduces costs and provides additional income from crops such as soybean and peanut. This paper discusses the soil health improvements that are being obtained with this new farming system, particularly its beneficial effects on soil carbon levels and soil biological properties. It also summarises research showing that breaking the sugarcane monoculture with a soybean or peanut crop reduces populations of lesion nematode (Pratylenchus zeae) and root-knot nematode (Meloidogyne javanica), the two most important nematode pests of sugarcane. The role of minimum tillage and inputs of organic matter in enhancing the natural biological control mechanisms that suppress these nematodes is also discussed. The paper then considers the farming system currently used for vegetable crops such as tomato, capsicum and rockmelon, where inadequate crop rotation, excessive tillage, low organic inputs and the fallowing and solarisation effect of covering beds with plastic leads to a situation where soil fumigation is seen as the only option for reducing losses from soilborne pests and pathogens. Since the sugar industry coexists with the vegetable industry in some areas of Australia, the paper argues the case for developing minimum tillage practices for vegetable production and integrating them into the sugarcane farming system. It concludes that a farming system of this nature would improve profitability in both industries, produce better environmental outcomes at a landscape level and provide more sustainable solutions to nematode and soilborne disease problems. © Australasian Plant Pathology Society 2008.