As a consequence of the industrial progress in the last decades a great amount and variety of residues has been generated. An alternative for the final disposition of this material has been its application to the soil. The use of these materials in the agriculture became an attractive alternative as from the point of view of recycling of nutrients as well as of the economical point of view. This research was developed with the objective of evaluating the effect of industrial sludge addition (LETRIP) in accumulation of nitrogen, nodulation and in soybean yield of Celeste cultivar in a Planossolo area (Fragiudult) of UFRRJ. The treatments were set by doses of 0, 25, 50 and 100 Mg ha-1 of sludge in a randomized block design, with three replications (12 plots). The soybean was planted from January 13th to 20th, 2005, approximately 40 days after sludge application. The total number of nodules was reduced in the doses of 25 and 50 Mg h-1 of LETRIP. Productivity greater than 4100 kg ha-1 was obtained with the highest dose of sludge and with a minimum increment of 1224 kg ha-1 when compared to the testimony, showing the potential of the residues for substituting mineral fertilizers in agricultural. However, caution is necessary when equilibrating rations between organic and mineral N (N-NH4 + N-NO3), what should be monitored with the time.
Glycine Max; biosolids; organic carbon; nitrification; leaching
