Variabilidad espacial en las propiedades químicas del suelo en un sistema de producción con cerdos en pastoreo.

Outdoor swine production is an alternative for family farmers, but recent research has shown that they can negatively alter soil chemical properties. To study the causes of degradation and management alternatives, it is necessary to have local information on the type and distribution of impacts. The aim of this work was to study the spatial variability of soil chemical characteristics in the surface layer (0-12 cm) of a Brunosol (Canelones, Uruguay) under an outdoor swine production system in comparison with a control soil (without pigs). Sampling was made in a grid (5x5 m) in 4 plots to map spatial variability. Based on this, a second sampling was performed in a control area and 6 plots (1500 m2 each), with 3 different management areas (service, grazing and intermediate) per plot (n = 24). We measured organic carbon (SOC), NO -N, NH -N, P 3 4 (Bray) and in solution, pH and electrical conductivity (EC). In the service area, the concentration of nitrate-N, available P, P in solution and EC increased significantly in relation to the control, whereas NH and SOC decreased. In the grazing area, available 4 P increased, while NH , COS and pH decreased. Spatial 4 variability of N, phosphorus and CE was influenced by the distance to the service. The system generated spatial heterogeneity, increasing ecological risks associated with N and P losses and decrease in SOC.