Spatial variability of soil fertility in areas cultivated with grains in the region of Paragominas, Pará state, Brazil

Abstract

The application of precision agriculture techniques in the management of soil fertility has optimized the use of fertilizers, enabling more sustainable agricultural systems. In this study, we aimed to assess the spatial variability of soil fertility in areas cultivated with grains in the region of Paragominas, Para state, Brazil. The study was conducted in 17 farms in 2009 and 2010. We measured 1945 soil samples collected at the 0-0.20 m depth. The following variables were analyzed: pH, V%, m%, sum of bases, K, Ca, Mg, Al, CEC, CEC t, P, and OM. The results were evaluated by means of descriptive statistics and frequency distribution. The soils cultivated with grains presented low acidity; base saturation below 50%; medium to high values of K, Ca and Mg. The levels of available P in the soil were considered low or very low in over 40% of the soil samples analyzed, constituting the most limiting factor to production.