Soil quality under integrated crop-livestock system in the Pampa Biome

Abstract

The increasing level of soil degradation has promoted the adoption of agricultural management that combines agricultural production to soil conservation. In this context, Integrated Crop-Livestock Systems have been successfully adopted, because they occupy the available resources in agroecosystems, concomitant to the improvement of soil quality. This study aimed to evaluate the soil quality in family farmers under integrated crop-livestock systems in the South Region of Rio Grande do Sul state, defining physical, chemical and biological indicators to detect the effect of the different management practices adopted in different use systems: native grazed field, ryegrass pasture and corn. Soil samples were collected in the layers from 0-0.05, 0.05-0.10 and 0.10-0.20 m to quantify the bulk density, total porosity, diameter weighted average, total organic carbon, total nitrogen, carbon of the coarse fraction, carbon associated with minerals, carbon of the free light fraction, carbon of the free occlude fraction, carbon of the heavy fraction, microbial biomass carbon and basal soil respiration. The factorial analysis applied to the 12 soil quality indicators, showed that the “Organic Matter Factor” was the one that most contributed to the total variation of the data in the three layers evaluated, being the most sensitive to detect the effects of the different management practices used. The indicators that compose the “Organic Matter Factor” are more associated to the native grazed field system, those that compose the “Aggregation Factor”, “Compression Factor” and “Microbial Carbon Factor” are more associated to the ryegrass pasture system. The indicators basal soil respiration, carbon of the free light fraction and total porosity are more related to the corn system. And finally, the bulk density is related to the three use systems evaluated.