MAPPING OF SOIL CONDITIONS IN PRECISION AGRICULTURE*

Ab s t r a c t. The present paper verifies the efficiency of the method for electrical conductivity (EC) measurement for the assessment of spatial variability of soil properties in precision agriculture. The verification was carried out in a 53-ha experimental field situated in South Moravia, Czech Republic. EC was measured using the EM-38 (Geonics Ltd, Canada) in 2004 and 2005. At the same time, topsoil samples were taken for agrochemical analyses of P, K, Mg, Ca, humus content and pH value, and for soil texture analysis. A strong correlation between years of EC measurements (r2 = 0.936) was found, which confirms the stability of EC measurement from a short-time point of view. Strong relationships between EC and clay content (r2 = 0.548) as well as sand content (r2 = −0.406) confirm the influence of soil texture on EC. Furthermore, almost all examined agrochemical characteristics (P, K, Mg content and pH value) and humus content show relatively balanced, moderately strong correlations with EC. It indicates that the soil EC measurement is a suitable tool for mapping field spatial variability of soil conditions. This information can be used mainly for directed sampling when locations of soil sampling points are determined by preliminary knowledge of field heterogeneity – EC maps. In contrast to traditional grid sampling, reduction in soil samples and at the same time keeping the level of soil maps details can be expected. K e y wo r d s: soil electrical conductivity, spatial variability, precision agricultur