Abstract

SANZANO, G. Agustín et al. Effect of crop residue and superficial soil properties on hidric erosion in soybean monoculture. Rev. ind. agríc. Tucumán [online]. 2008, vol.85, n.1, pp.23-30. ISSN 1851-3018.

In a soil management trial that conducted for 23 years in Monte Redondo, Tucumán, runoff and infiltration coefficients, soil losses, total organic carbon and available phosphorus were evaluated using a rainfall simulator. Before the rainfall simulations, some surface soil properties, such as organic carbon, bulk density, aggregate stability, hydraulic conductivity and basic infiltration were also evaluated. The treatments were: no-tillage cropping systems with 0%, 40% and 80% crop residues (SD₀, SD₁ and SD₂ respectively); chisel plowing (LV) before sowing and natural vegetation (MN) as the blank treatment. Total organic carbon, aggregate stability and basic infiltration decreased significantly from MN to LV. Even though there were no differences in bulk density and hydraulic conductivity between LV and SD₀, they differed significantly when compared with MN. Runoff coefficients were significantly higher in LV when compared with no-tillage systems; however, there were no differences between crop residue rates in the no-tillage treatments. Soil losses in SD₁ and SD₂ were 48% and 62% lower than in SD₀. Aggregate stability was the surface soil property that had the highest relationship with soil losses in the treatments without crop residue ( R²=0.92). Cumulative infiltration after an hour of rain was 24.2 mm in the SD₀ treatment, 15.3 mm in LV and 34.7 mm in MN. In the LV treatment total organic carbon and available phosphorus concentrations were almost twice higher than in SD₀, while SD₁ and SD₂ showed soil losses even three times lower than SD₀.

Keywords : Runoff; Erosion; Crop residues; Aggregate stability.

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