Physical attributes of soil fertilized with sewage sludge and with calcium and magnesium silicates

This study aimed to evaluate the effect of sewage sludge and calcium and magnesium silicate on the physical attributes of a Cambisol cultivated with sunflower. The treatments were arranged in a factorial (4 x 2) + 1, corresponding to four doses of sewage sludge (0, 6.25, 12.5 and 18.5 t ha-1, in dry basis), two doses of calcium and magnesium silicate (0 and 240 g m-1) and an additional treatment with chemical fertilizers. The experimental design was randomized blocks with three replications. After 150 days of fertilization, were collected soil samples at depth of 0-20 and 20-40 cm for the evaluation of bulk density, particle density, total porosity, water dispersible clay, flocculation index, aggregate stability index, mean weight diameter, geometric mean diameter and soil penetration resistance. The additional treatment, corresponding to chemical fertilizer, did not differ from the corresponding treatments with sewage sludge fertilizer and calcium and magnesium silicate in relation to soil physical attributes. For calcium and magnesium silicate, also were not found differences in soil physical characteristics between dose zero and 240 g m-1. On the other hand, the application of sewage sludge to soil decreased the water dispersible clay and increased the soil total porosity, the clay flocculation index and wet aggregate stability index. There was no influence of sewage sludge on the other attributes physical of soil.

Biosolids; organic matter; soil bulk density; aggregate stability

Universidade Federal de Viçosa Av. Peter Henry Rolfs, s/n, 36570-000 Viçosa, Minas Gerais Brasil, Tel./Fax: (55 31) 3612-2078 - Viçosa - MG - Brazil