sewage sludge is a residue from waste water treatment plants and vinasse is a main effluent from alcohol distilleries. the main differences between them are observed in the nitrogen (n) and potassium (k) contents. sewage sludge is poor in k, and the vinasse in n. this research was carried out to evaluate sewage sludge and vinasse effects on the nitrogen contents of the plant-soil system and the effects of their application on planted-cane and 1st. ratoon-cane under field conditions, on a typic haplustox, in pontal, state of s？o paulo, brazil, using the sugarcane cultivar sp81-3250. a randomized blocks experimental design was used with 13 treatments and three replications. the results were organized in a 3 × 2 × 2 factorial scheme (three residue forms, two application modes and two rates of n or k) and a control treatment (mineral fertilization). sewage sludge provided the highest n plant contents and the highest residual n soil contents. sewage sludge and vinasse can replace mineral fertilization for both planted-cane and 1st. ratoon-cane.