Chemical properties of Yellow Latosol of the Cerrado in the Piauí state under different management systems

Abstract

The cerrado region of the Piaui State is considered the last brazilian agricultural frontier. Its sustainability depends, among others factors, of the adopted management systems. The objective of this work was to evaluate the changes in the chemical attributes of a dystrophic Yellow Latosol, under different management systems: no-tillage (NT), conventional tillage (CT) and just-deforested area (JDA), compared to native cerrado vegetation (NC). The soil samples were collected in the Progresso Farm, in Uruçuí, PI, in the 0-5; 5-10; 10-20 and 20-40cm depths. pH in water (1:2.5), Al³⁺, H + Al, Ca²⁺, Mg²⁺, K⁺, available P and organic matter (OM) were evaluated. The soil cation exchange capacity at pH 7.0 (T), sum of basis (SB), basis saturation (V) and the saturation for aluminum (m) were determined. In all the soil depths, the Al^{3 +} was lower in the NT and CT systems. NT and CT also presented the highest (p<0.05) available P and Ca and Mg exchangeable, at 0-5; 5-10 and 10-20 cm depths. There are no differences between NT and CT, except to the 10-20 cm depth, for V, SB and OM variables. Change of the native vegetation to NT and CT promoted alterations in soil chemical properties. The adoption time (3 years) of the NT was not enough to increase the fertility of the Yellow Latosol, compared to CT, in cerrado of the Piauí state.