Aggregation and organic matter under alfisol soil tillage for Eucalyptus plantation

Abstract

Aggregation can suffer permanent or temporary changes to cyclical variations induced by management practices for soil and plant growth. The study evaluated the temporal and spatial variation of the stability of water stable aggregates and its relationship with the organic matter content in an Hapludalf in Santa Maria municipality, Rio Grande do Sul State, Brazil. The treatments were four tillage systems for deployment of Eucalyptus grandis: no-tillage, chisel, chisel tillage plus harrowing and rotary tiller. Soil samples were collected in the layer of 0.00 to 0.05 m for determination of the density, and stability in water of stable organic matter aggregates contents of the soil. Chisel, chisel tillage plus harrowing and rotary tiller resulted in lower structural stability of water stable aggregates. The negative effects of tillage on Hapludalf with sandy loam texture are reduced after 12 months, demonstrating its ability to restore the structure and aggregation. The soil tillage evaluated did not increase the carbon content and that was not influenced by the state of aggregation. The early growth of Eucalyptus was favored by the intensification of soil tillage.