A ROLE FOR SOIL EM MAPPING IN PRECISION AGRICULTURAL PRACTICES FOR SUGARCANE PRODUCTION

THE application of precision agricultural techniques in cropping systems depends on the recognition of geo-referenced zones within paddocks. The zones provide a framework for growers who wish to make site-specific decisions in applying appropriate management practices to individual areas within paddocks. In this way, input levels can be targeted for cost-effective production, minimised waste, and reduced environmental impacts. The management decisions must be underpinned by sound knowledge of variations in the underlying soil properties. In the northern Australian sugar industry, however, there are few areas where detailed soil maps are available at a scale meeting the requirements of precision agriculture. Given the cost and time involved in making conventional soil surveys, surrogate methods are gaining popularity for detecting variations in soil properties at a cane paddock and sub-paddock scale. The methods include the use of electromagnetic induction mapping (commonly known as EM mapping and based on the electrical conductivity of the soil), processed satellite imagery, and geo-referenced sugarcane yield monitoring. EM mapping has been used extensively in the past for identifying soil salinity hazards. With the development of accurate geo-positioning and computerised spatial data management technologies, the method is evolving into a tool for defining variations in soils on a sub-paddock scale. This paper reviews some of the advantages and potential of applying EM mapping methods to precision agricultural practices, utilising the wealth of spatial data that is relatively cheaply and readily available. It is concluded that EM mapping techniques provide a useful tool that may be used to help underpin new strategies for best management practice for improved sugarcane production and enhanced stewardship of natural resources.