Biological properties, humic acids and heavy metals availability in Ferralitic soil under differents agricultural uses

Abstract

The biological properties and the organic matter of the soil can reflect the imbalance of a certain atmosphere, the sustainability of the agricultural practices and to predict processes of contamination. The objective of this work was to evaluate the effect of three different agricultural uses (fruit-bearing, cane of sugar and potato) in soil moisturized Red Ferralitic, on the properties biological basal breathing, microbial mass and the metabolic quotient. The organic carbon was also evaluated, as well as the optic coefficient E₄/E₆, the threshold of clotting and the content of groups functional acids in the sour extracted humic of those soils. Also, the contained pseudototal of cations of heavy metals was determined Cd²⁺+, Cu²⁺+, Ni²⁺+, Pb²⁺and Zn²⁺. The results demonstrated that the uses of cane of sugar and of potato, they showed the lowest values in basal breathing and microbial mass, with high metabolic quotient, what indicates an unfavorable effect of the intensity of the practices agricultural employees on the microbiota edaphic. The organic carbon showed significant differences among the management. In the humic acids structural modifications were detected, reflected in the threshold of clotting and in the optic coefficient E4 /E6, as well as in the content of groups functional acids. The contained pseudototal of heavy metals was superior in the uses of bigger quantity of cultural activities, especially in the corresponding to the cultivation of the potato, where the Cd²⁺is in relatively high concentrations, that which constitutes a given risk its low limit of tolerance in foods.