Caracterização de propriedades edáficas em áreas sob manejo orgânico e natural na região serrana do Estado do Rio de Janeiro

Abstract

This work was accomplished in Nova Friburgo, highland region of Rio de Janeiro State. It was studied two rural properties whose producers use organic and natural management of the soil. The natural management differs from the organic for not using crop rotation and organic fertilization with animal dejections. The two rural properties present distinct soil classes; therefore, a comparison among the two soil management systems was not possible. The study had as main objective to evaluate the degree of modification of soil properties in areas submitted to organic and natural management. In each area soil samples were collected under crop areas and control. In natural management, the control was a fallow area. In organic management, the control was a secondary forest area. The results showed that in the area under natural crop management levels of Ca, Ca+Mg, P and pH in water were statistically higher, when compared to the control. For H+Al, the highest values occurred in the reference area, when compared to cultivated areas. In the organic management, higher values of Ca, Ca + Mg, Na, K and P were observed in the crop area in all depths. However, for H + Al and NO3-, the higher values were found in the control area. A degradation of the soil physical properties in the area under natural management was indicated by variation in aggregate stability and soil bulk density, but the organic management has benefited those properties. The selected and evaluated variables were capable to discriminate the different management systems studied by the main components analysis.