The environmental benefits of agroforestry system are well documented in many regions of the globe. However, works documenting the advantage of this kind of soil management system on soil quality in the cearense semi-arid region are very scarce. The aim of this work was to evaluate the impact of agroforestry and conventional systems on the physical and chemical soil characteristics, after five years of experimentation in the semi-arid region, Ceará, Brazil. The experiment consisted of seven treatments: agrosilvopasture (AGP), silvopasture (SILV), traditionally cultivated in 1998 and 1999 (TR98), traditionally cultivated in 2002 (TR02), intensive cropping (CI), and two native forests (MN-1 and MN-2). Soil samples were collected at four depths: 0-6, 6-12, 12-20 and 20-40cm. Soil quality was evaluated by the following physical and chemical characteristics analyzed: granulometry, clay dispersion, aggregate stability, exchangeable elements, soil pH and total organic carbon (COT). The treatments AGP, TR98 and CI reduced the COT content due to intensive soil management. Chemical characteristics, such as exchangeable cations, CEC, and pH varied as a function of clay content in SILV and MN-2, whereas in CI and TR98, there was reduction in these characteristics due to the intensive soil management. The AGP treatment seems to improve the nutrient cycle, however, the intensive soil management, and the consequent reduction in COT content also originated reduction in aggregate stability. Results allowed to recommend the SILV treatment in order to maintain soil quality and food production in the cearense semi-arid region.
Organic matter; semi arid; nutrient cycling; soil quality
