EFFECT OF PERENNIAL PASTURES ON THE STRUCTURE OF MOLISOLES, OF THE PAMPEAN SEMIARID REGION. PART II

Abstract

The purpose of this study was to characterize indicators that reflect the structural stability in soils influenced by different land uses. To determine if these indicators related to the stability structure under the mixed rotation approach (annual crops-pastures) are close to the levels of the indicators under the use with permanent grass pasture, considering the structural parameters of this soil as a baseline. Three different land uses were selected on petrocalcic Paleustolls, corresponding to long-term trials, permanent grassland of weeping grass (LL) considered as baseline soil, perennial pastures of fescue + wheatgrass (F+A) and Lucerne + wheatgrass (A+A) and agricultural use (Ag). Organic matter content and its fractions, aggregate size distribution, mean weight diameter, aggregate porosity, structural stability and erodible fraction were determined. Results showed that the relative values ​​of the indicators evaluated in the two perennial pastures (F + A and A + A), were found closer to LL values than to Ag use. Perennial pastures (both grasses and legumes) contributed significantly to the structural properties determining soil quality, improving physical and biological fertility.