Nitrogênio e água como fatores de produtividade do trigo no cerrado

Two experiments were carried out at Embrapa Rice and Beans, located at the municipality of Santo Antonio de Goias, Goias state, Brazil, under no-tillage in the soybean straw, to evaluate the effects of irrigation management and nitrogen doses on the grain yield and its components of two wheat cultivars. In the first experiment, the irrigation was started at soil-water tension of 40 kPa, and in the second one, at soil-water tension of 60 kPa. For both experiments, a randomized block design with subdivided plots, with four replications, was used. In the plots were established five doses of nitrogen (0, 50, 100, 150, and 200 kg ha-1) and, in the subplots, the cultivars EMBRAPA 22 and EMBRAPA 42. Soil-water tension of 60 kPa was more adequate for management of irrigation in wheat, since it did not affect its grain yield and quality and used less water. The dose of nitrogen that promoted maximum technical efficiency was 73 kg ha-1. The crude protein content increased as nitrogen increased. The increase of irrigation frequency and nitrogen decreased the hectoliter-grain weight.