Variabilidade espacial da produtividade do feijoeiro correlacionada com atributos químicos de um Latossolo Vermelho Distroférrico sob sistema de semeadura direta

Abstract

The bean, an important source of protein, is a very important and nutritive food in the diet of Latin-American population, being Brazil the larger world producer of this vegetable. Its cultivation under no-tillage system has increased year after year. In 2002, the spatial variability of the bean yield was evaluated under no-tillage system in a Dystropherric Red Latosol (Typic Acrustox) of the Brazilian Savannah. The main purpose of this study was to select the soil attribute that have the best spatial and linear correlation with bean yield. A geostatistical grid, with 135 sampling points, was installed to collect the soil and plant data in an area of 7,500 m 2. The bean grains productivity (GP) was the plant attribute, while the soil ones were: P, OM, pH, K, Ca, Mg, H+Al, S, CEC and V%. Linear relationships, simple and multiple, were calculated between the GP and the soil attributes. The semivariograms were adjusted for all the attributes, obtaining krigings and cross-validations and also evaluating the co-krigings between the GP and the soil attributes. In relation to the bean grain yield, around 22% of its variation was attributed to the variation in the soil chemical attributes. From both linear and spatial view points, the soil pH was a good indicator of the bean grains yield under no-tillage system.