EDAFOLOGÍA, VOL 14. (1, 2, 3), PP 25-34 2007
EFECTO DEL SISTEMA DE LABOREO Y MANEJO DE RESIDUOS SOBRE LA ESTABILIDAD DE LOS AGREGADOS EN UN OXISOL (BRASIL)
Taboada Castro1, M. M., Alves2 M. C., Whalen3, J., Taboada Castro1, M. T.
1Universidad de A Coruña. Facultad de Ciencias. A Zapateira. CP. 15071.
A Coruña. 2Universidade Estadual Paulista. Faculdade de Engenharia. Ilha Solteira-SP,
Brasil. 3McGill University. Faculty of Agricultural and Environmental Sciences.
Montreal. Canadá.
E-Mail: [email protected]
Tillage systems and inadequate management of crop residues may cause temporary or permanent changes in soil structure. In this survey was assessment the influence of the tillage and crop residues management on structural stability in a soil of savanna transformed in agricultural land. During five years was established a crop rotations consisting of beans/cover crops/soybeans under two management systems: conventional tillage (CT) and no-tillage (NT). we assesment the influence of tillage and management of crop residues on the structural stability, using the size distribution of water stable aggregates and by the mean weight diameter(WMD). In all treatments, the largest proportion of aggregates was in the class > 4mm, although LC and NL decreased between 13 and 56% compared to the natural soil. Tillage systems differed in the ability of soil aggregation. The MWD in conventional tillage was significantly higher than in no-tillage systems. This fact was related to the time of sampling and also with phenomena of compression. Among the cover crops crotalaria (Crotalaria juncea), guandu (Cajanus cajan) and millet (Pennisetum americanum) showed positive effects on the stability of aggregates when are cultivated under no-tillage systems.
Key Words: aggregate stability, conventional tillage, no-tillage, cover crops.