Influence of Eucalyptus and Grassland on Organic Carbon and Soil Water Infiltration

Abstract

The Modern agriculture requires cost-effective techniques to produce food and raw materials without degrading the environment. In order to achieve this objective it is essential to optimize the soil and the water use and to preserve water and organic carbon. The objective of this paper is to evaluate the plant cover's influence on the concentration of organic carbon and water infiltration in the soil. The experiment was conducted in the Brazilian's Cerrado, in the city of Três Lagoas, in the of Mato Grosso do Sul State, characterized by the Aw climate (hot and humid, with a dry winter season), average temperature of 24,2°C and average precipitation of 1240mm. This region has been widely cultivated with eucalyptus and pastures. Infiltration rate and cumulative infiltration assessments were performed with the mini disk infiltrometer. Density and porosity in undisturbed soil samples, and organic carbon content were determined from 0.0 to 0.30m deep. The experimental design was randomized and consisted of four treatments (Cerrado-C, Eucalyptus 02 years-EU2, Eucalyptus 15 years-EU15 and Pasture-P), which evaluations were conducted in a grid of 36 points, divided into 4 blocks with 9 replications, per treatment. We compared the four analyzed areas. The Cerrado, which is a preserved area, presented higher infiltration rate (ŷ (C)=-2800ln (x) +8,623.9; R²=0.9465), higher organic carbon content (9.5 g dm -³), lower density (1.26 g cm ³), and higher total porosity (47.90%). Whereas the Eucalyptus (both 2 and 15 years) and Pasture's areas showed similar behavior, characterized by lower infiltration rates (ŷ(EU2)=-362.5ln(x)+1,051.6; R²=0.9772, ŷ(EU15)=-180.6ln(x)+523.59; R²=0.9064 e ŷ(P)=-429.37ln(x)+757.67; R²=0.9237), lower organic carbon 1 Mestranda em Agronomia, UNESP, Ilha Solteira -São Paulo.ALVES, M.C.; CABENA, M.S.V. Infiltração de água em um Podzólico Vermelho-Escuro sob dois métodos de preparo, usando-se chuva simulada com duas intensidades. Revista Brasileira de Ciência do Solo, Viçosa, V.23, p.753-761, 1999. ALVES SOBRINHO, T.; VITORINO, A.C.T.; SOUZA, L.C.F.; GONÇALVEZ, M.C.;CARVALHO, D.F. Infiltração de água no solo em sistemas de plantio direto e convencional.