Nitrogen fertilization of wheat grown under no-tillage after different cover crops

The performance of irrigated wheat grown under no-tillage in succession to different cover crops were evaluated in relation to nitrogen topdressing fertilization. The experiment was carried out at Embrapa Rice & Beans, in the municipality of Santo Antonio de Goias, GO, on a Dystrophic Red Latosol. The treatments applied to the main plots were seven cover crops: (Brachiaria brizantha (Hochst. ex. A. Rich.) Stapf.) cv. Marandu; B. brizantha associated with corn (Zea mays L.); pigeon pea (Cajanus cajan (L.) Millisp); millet (Pennisetum glaucum (L.) R. Br.); Panicum maximum (Jacq.) cv. Mombaca; sorghum (Sorghum bicolor (L.) Moench); and (Stylosanthes guianensis (Aubl.) Sw.) cv. Mineirao. The bean crop was seeded on the cover crop mulches to study the response of wheat to nitrogen topdressing fertilization. Four nitrogen doses, 0, 30, 60, and 120 kg ha(-1), in the form of urea, were used. Wheat grain yield on corn associated with B. brizantha, pigeon pea, sorghum, and S. guianensis mulches showed a quadratic response to nitrogen fertilization. The response was linear on B. brizantha and millet mulches and there was no response on P. maximum mulch. The highest responses of wheat grain yield to nitrogen topdressing fertilization were obtained when wheat was grown in succession to sorghum and B. brizantha cv. Marandu.