Atributos físicos e químicos do solo sob diferentes usos em unidades de produção da agricultura familiar: estudo de caso da propriedade Zanette em Chapecó, SC

Abstract

The West Santa Catarina region is characterized by the predominance of small farms, in which the predominant production systems combine annual crops and animal husbandry, including dairy cattle production, which has grown significantly in recent years. The region has clayey soils that, when intensively used and inadequately managed, are susceptible to excessive compaction. The regional topography is rugged, and the climate is characterized by high rainfall, with intense rains in the spring and early summer. This study aimed to evaluate the soil of a small farm (Propriedade Zanette) in the West of Santa Catarina, in Chapecó, where the soils have been intensively cultivated for over 35 years, with annual crops and pastures for dairy cattle production. The evaluated areas included five plots with different land uses: corn crop for silage and winter annual pasture; soybean and wheat crops; perennial pasture of Axonopus compressus, pasture of Cynodon spp. overseeded with black oat and ryegrass; native forest. In each area soil samples were collected in four trenches, at depths of 0.00-0.05, 0.05-0.10, 0.10-0.15, and 0.15-0.20 m for physical and chemical analysis, and soil penetration resistance (RP) was measured. The parameters evaluated were: pH in water (pH), organic matter content (MOS), porosity (total - PT, macro - Mac, and microporosity - Mic), soil density (Ds), saturated hydraulic conductivity (Ksat), particle size distribution, and water-dispersible clay (ADA). The native forest showed lower values of pH, Ds, Mic, PR, and ADA, and higher values of PT, Mac, Ksat, and MOS than the areas under agricultural use. The soybean crop area had the highest pH values (6.7) and DS (1.37 Mg/m³), while the Axonopus compressus grass area had the highest RP value (2.9 MPa) and the lowest Mac value (10.7%). The soils under agricultural use on the farm showed compaction, with increased RP and reduced Ksat, indicating soil management problems.