With the increase of corn cultivation under the no-tillage system, various cover crop species have been evaluated to obtain a soil cover that benefits corn under succession and no-tillage. The objective of this work was to evaluate the effect of three sowing densities of black oat (Avena strigosa Scheig) and common vetch (Vicia sativa) in associated crops and as isolated crops and three levels of nitrogen fertilization (N), applied on corn (0, 60 and 160 kg ha-1 of N). Dry matter yield of the cover crop species was similar in associated systems and as isolated crops. The increase in the amount of N applied and the increase in the proportion of common vetch seeds in the associated systems increased the amount of N accumulated by corn plants. There was no interaction between the amount of N applied and the soil cover systems for corn grain yield. Without N fertilization, corn grain yield increased 321 kg ha-1 for each 10% of substitution of oat for common vetch in the associated systems. With 60 kg ha-1 of N, the response was quadratic. With the 160 kg ha-1 of N, there was no effect of soil cover on corn grain yield. Grain yield of corn cultivated after oat as isolated crop or associated with common vetch increased linearly with the increase of the amount of N fertilizer applied in corn. Under succession, using common vetch as an isolated crop, there was no response of corn grain yield to N fertilization.
no-tillage; corn yield; nitrogen