Abstract

FERNANDEZ, Romina et al. Effect of perennial pastures in physical and biological ertility in mollisols of the semiarid pampas region. Cienc. suelo [online]. 2020, vol.38, n.1, pp.133-148. ISSN 1850-2067.

The objective of the study was to characterize soil porosity in different land uses and to determine if physical-hydric indicators under mixed rotation (annual crops-pastures) will approach to the levels of land use with permanent grassland (baseline) in loam soils of Semiarid Pampas Region. Three different land uses were selected on petrocalcic Paleustolls, corresponding to long-term trials: permanent grassland of weeping grass considered as baseline soil (LL), perennial pastures of fescue + wheatgrass (F+A) and Lucerne + wheatgrass (A+A) and an agricultural use (Ag). On each soil use, indicators such as organic matter, bulk density, maximum bulk density, relative compaction, critical moisture content, total porosity, macroporosity, penetration resistance, infiltration and quantity of roots were determined. The values of the indicators evaluated in the two perennial pastures (F+A and A+A), were closer to the values of LL than to the Ag use, and particularly the A+A pasture was the closest to the reference situation. Land use had a greater incidence in the 0-6 cm depth in most of the indicators, although the results show the important contribution under the A+A use in total porosity, macropores, bulk density and roots at greater depth (6-12, 12-18 cm). These results demonstrate the potential of perennial pastures, especially if they include leguminous species, in the recovery of physical and biological fertility in soils that are in degradation process.

Keywords : long-term trials; baseline values soils; physical-hydric indicators.

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