The objective of this work was to evaluate nitrate leaching caused by applications of sewage sludge and mineral fertilizer in a Typic Haplustox cultivated with mayze. N aplication rates in five crops, in the treatment with mineral fertilizer (AM), were 51, 90, 100, 90 and 100 kg ha-1. In the sludge treatments (L0N, L1N, L2N, L4N and L8N), the rates of available N applied to each crop were equivalent to zero, one, two, four, and eight times those of AM. N-NO3- leaching occurred in all treatments, following the order AM<L0N<L1N<L2N<L4N<L8N. Mean total losses of N-NO3- in treatments L1N, L2N, L4N and L8N reached 430, 1,020, 2,400 and 3,970 kg ha-1, respectively (28, 42, 54 and 45% of the total N applied, respectively). Treatments L2N, L4N and L8N showed the greatest soil solution N-NO3- concentrations during the fourth crop, with peak values varying between 86 mg L-1 (treatment L2N) and 464 mg L-1 (treatment L8N). In treatments AM, L0N and L1N, soil solution N-NO3- concentrations during the fourth crop varied from 5 to 9, 19 to 36, and 33 to 71 mg L-1, respectively.
soil solution; contamination; biosolid; nitrogen losses
