Resumo

FERNANDEZ, Romina; LUCAS, Milagros María Rosa; PAINEMILLA, Lorena de los Angeles  e  QUIROGA, Alberto. Effect of perennial pastures on the structure of molisoles, of the semiarid pampas region. Part II. Cienc. suelo [online]. 2021, vol.39, n.2, pp.84-105. ISSN 1850-2067.

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.

Palavras-chave : structural stability; perennial pastures; long-term trials.

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