Biofertilization of Tifton 85 with Sludge from Sewage Treatment Station of Whey Industry

The high concentration of N, P and other components present in sludge from wastewater treatment plants make it economically interesting the application in agricultural crop, as soil biofertilizer. The objective of this study was to evaluate the influence of the application of biological sludge, from an effluent treatment plant, in Tifton 85 crop, observing the performance of the sludge as biofertilizer and, finally, evaluating the bioaccumulation of nutrients and metals in the leaf tissue of plants biofertilized with the sludge. The experiment was carried out in completely randomized design (CRD), with application of five doses of dehydrated sludge, being the applied doses of 0, 10, 20, 30 and 40 m³ ha^-1, in six replicates. After 47 days of application of sludge, the forages were cut to 12 cm from soil, stored and dried, for further determination of dry mass and bioaccumulated contents of P, K, Ca, Mg, Cu, Zn, Fe, Mn, Pb and Cr. The application of sludge to soil did not present negative influences on the development of Tifton 85 forage, having contributed significantly to the increase of N, P and CP. However, at sludge doses above 50 mg kg^-1, Mn leaf contents reduced Fe absorption by plants. There was no significant absorption of metals such as Cr, Cd and Pb by the plant.