Efectos de las pasturas perennes en la estructura de molisoles, de la región semiárida pampeana

Abstract

El presente trabajo tiene como objetivo evaluar la condición estructural de suelos influenciados por distintas prácticas de uso. El estudio se desarrolló en la Región Semiárida Pampeana sobre Paleustoles petrocálcicos, se seleccionaron suelos de textura franca, bajo 3 usos diferentes que corresponden a ensayos de larga duración: pastura permanente de pasto llorón (LL) (60 años) el cual fue considerado como línea base o de referencia; pasturas perennes: festuca+agropiro (F+A) y agropiro+alfalfa (A+A); y por último un suelo bajo uso agrícola.

Current agricultural production systems mainly use annual crops with a high proportion of oilseeds in the rotation. This implied less root contribution and lower residue biomass on the soil surface, which led to organic carbon losses and weakened soil structures. The objective of the study was to evaluate the structural condition of soils influenced by different land use. The study was carried out in the Semi-arid Pampean Region on petrocalcic Paleustolls, loamy texture soils, under 3 different uses were selected that correspond to long-term trials: permanent pastures of weeping lovegrass (LL) (60 years) which was considered as baseline or reference; perennial pastures of fescue+wheatgrass (F+A) and wheatgrass+alfalfa (A+A); and finally, a land under agricultural use. Aggregate size distribution, organic matter content, weight of a thousand aggregates, aggregate porosity, structural stability, and erodible fraction were determined. These structural quality indicators showed that both perennial pastures (F+A and A+A) were closer to LL values than to agriculture. Therefore, including perennial pastures in the rotation (both grasses and legumes), contributed significantly to the structural properties determining soil quality, improving its physical and biological fertility.