Variabilidade espacial da umidade de um Latossolo Vermelho-Amarelo sob plantio direto

Abstract

The study of spatial dependence of soil attributes is important to improve management practices and sampling. This research aimed to investigate the spatial and temporal variability of the soil water content of a Red-Yellow Latosol under no-tillage cultivated with maize and its relation to the total organic carbon in soil, macroporosity and microporosity. The experiment was on experimental area located in Lavras, state of Minas Gerais, Brazil, which was implanted an experimental mesh with dimensions 90 x 90 m (0.81 ha of area) and spacing among points equal to 15 x 15 m . For a more detailed spatial dependence of data, it was realized the introduction of two more meshes (zoom) in a quadrant of the great mesh, totaling 73 reading points. The soil water content in base volume (cm3 cm-3) was determined on two dates, using an equipment that is based on the technique of Time Domain Reflectometry (TDR). Through the analysis of data from two dates with classical statistical, it was observed average coefficients of variation for soil moisture. It was obtained a semivariogram with pure nugget effect to a wetter soil, indicating a total lack of structure for soil moisture. For the drier soil, it was found that the association between soil moisture and organic carbon increased and fit the exponential model to semivariogram, which showed moderate spatial dependence and range equal to 75 m.