Some plants for mulching have the capacity to increase the availability of nutrients in the soil - nitrogen in particular - for crop succession, thus producing positive effects on the interaction between mineral fertilizer and green manure. As a result, there is a greater possibility to obtain higher incomes than by using each one separately. The objective of this study was to evaluate the effect of antecedent crops, levels and sources of nitrogen on yield compounds and foliar nitrogen content of maize by means of no-tillage system. These were constituted by crops preceding maize, i.e., black oat, wheat, pasture turnip, hairy vetch and one fallow treatment during winter. Subplots were established by four levels of nitrogen (0; 50; 100 and 200 kg ha -1 of N), which were applied as cover. Sub-subplots were represented by two sources of nitrogen (ammonium sulfate and urea). Results showed that antecedent crops had some influence upon yield, mass of 1000 grains and foliar nitrogen content of maize. The highest yield of maize was obtained after the winter rest, the pasture turnip and also in the absence of nitrogen fertilizer application as cover. Maximum yield of maize was also obtained when sowing was done after wheat and black oat, in nitrogen levels of 140 and 137 kg ha -1, respectively. The nitrogen sources utilized had some influence only upon the index of harvest, the number of grains per ear and the foliar nitrogen content.
