Abordagem das correlações: condutividade hidráulica saturada, carbono orgânico e atributos físicos do solo em sistema silvipastoril no semiárido

Abstract

Understanding the dynamics of water in the soil is of paramount importance for the development of agricultural and silvopastoral systems. In this context, the saturated hydraulic conductivity (Ksat) is relevant to conclude about the flux and transport of water and sediments, and for soil water management strategies. As this parameter is influenced by the physical properties of the soil, it is also used to evaluate the effects of soil management, being fundamental for hydrological modeling studies. Thus, this research aims to analyze the existing correlations between Ksat, organic carbon and soil physical attributes in a silvopastoral system, through Pearson's linear correlations, to evaluate the interfering factors in soil water flow in a silvopastoral system (SSP). The study was developed in Serra Talhada, Sertão Pernambucano, and controlled through an experimental design in randomized blocks. A fragment of native forest of the caatinga biome was used as a reference area. Deformed and informed soil samples were collected between the depths of 0-0.10, 0.10-0.20, 0.20-0.30 and 0.30-0.40 m, for the province of Ksat, density , total porosity, macro and microporosity, granulometry, clay dispersed in water, particle density, total organic carbon, humic fractions, light organic matter and labile carbon. Simple correlations were shown as averages and applied between physical-hydric attributes and organic carbon. The textural classification did not change between the two areas, but the SSP showed the highest values of soil density and microporosity, and the highest macroporosity caused by animal trampling. The Ksat in the SSP is high and better than in the Caatinga area, due to the performance of the mesquite root system and the deposit of organic matter along the soil profile. The SSP showed a higher carbon stock only in the first soil layer evaluations (0 - 10 cm) due to the contribution of SOM from the feces of animals that graze in the area. Significant correlations were observed between organic carbon and its fractions with soil texture, demonstrating that granulometry is related to the level of transformation of soil organic matter. The results obtained for saturated hydraulic conductivity did not show a significant association with the fractions of soil organic matter, but the influence of physical attributes and SOM on soil aggregation and consequently on the flow of water in the porous medium is clear.