Decomposition of cropresiduesand nutrient release patterns are important from the nutrient cycling in agricultural systems. An Incubation experiments were conducted to examine the effect of corn, soybean, mixed corn and soybean residue and biocharon N mineralization. The experiments were carried out in randomized completely design with tree aplications. The treatments consisted of corns, soybeans, a mixture of corn and soybeans residues, biocharand control. The results showed that C and N mineralization was significantly increased in soils that were applied with residues compared with no residues during the incubation periods of 20 and 40 days after incubations. Decomposition rates are influenced by the N content of the residue. Soybean residue can release Nhigher than other residues. At the end of incubation, the percentage of C organic was as follows; soybean residues (2.47%), biochar (1.90%), corn + soybeans (1.86%), corn (1.80%) and control (1.75%). The Ntotal were ocurred with soybean residues (0.47%), biochar and corn + soybeans (0.15%), maize (0.12% and control (0.09%). Therefore, it can be conclude that soybean residues can be potential source of C-organic and mineral N.
