Spatial Variability of Soil Co2 Emission in Soybean and Sugarcane Areas in Mato Grosso Do Sul Cerrado, Brazil

Abstract

In last years, the damage caused to the environment due to anthropic activities have become a worldwide concern. The carbon dioxide (CO2) is one of the main greenhouse gases because the increase of its concentration in the atmosphere has intensified to global warming. Therefore, to study the CO2 amounts emitted to the atmosphere has been even more important, especially in agricultural areas in Brazil. This study aimed to determine the spatial variability of soil CO2 emissions (FCO2), soil temperature (Ts) and soil moisture (Ms) in soybean and sugarcane cultivation areas in the Cerrado region in Mato Grosso do Sul. The FCO2 and Ts registration were done using a portable flow chamber and temperature sensor of the LI-8100 system. The Ms was evaluated using TDR portable system. The studies were conducted in the years of 2013, in soybean cultivation, and in 2014, in the sugarcane cultivation, during the crop growth early stages, using grids which contain 89 and 102 sampling points, respectively, spanning 1 ha area in both experiments. The spatial variability variables were characterised by geostatistics: mathematical models adjustments to the experimental variograms and spatial pattern maps construction through ordinary kriging technique. The sTe sH variables did not show significant correlations with FCO2. Despite the years of conducting the experiments, the soybean cultivation presented the higher average values of soil CO2 emission equal 2.11 µmol m-2 s-1 and higher variation in range of the spatial dependency between 8.41 and 27 m when compared to sugarcane culture, with a FCO2 average of 1.71 µmol m-2 s-1 and variation in the ranges of spatial dependency between 15.3 and 27.3 m.