Practical applications of soil electrical conductivity mapping.

Abstract

The site-specific application of inputs such as seed, fertilizer and crop protection chemicals has the potential to reduce input costs, maximize yields, and benefit the environment. The economic returns currently received by the early adopters of precision farming methods need to be improved before wide-scale acceptance of this practice will occur. These improvements include cost-effective identification and management of the spatial variability of soil and nutrients, applying inputs based on each site's productive capacity, and correct decision-making using the available layers of information. Soil electrical conductivity (EC) measurements have long been used to identify contrasting soil properties in the geological and environmental fields. The purpose of this paper is to discuss the applications in precision farming where EC maps are proving useful in improving economic returns to precision farming. The usefulness of soil conductivity stems from the fact that sands have a low conductivity, silts have a medium conductivity and clays have a high conductivity. Consequently, conductivity (measured at low frequencies) correlates strongly to soil grain size and texture. One of the applications of an EC map, which will be covered in this paper, is to view it in conjunction with other information layers. Farmers practicing precision farming methods have a wide assortment of data layers to assist them in their decision-making: yield maps, fertility/grid sampling data, soil surveys, a grower's historical knowledge, and visible changes in soil appearance and topography. As soil serves as the growth medium for crops, it is a major factor affecting a crop's potential. This paper provides examples of how an EC soil map, along with other information layers, can offer a promising foundation for precision farming.