Toward increasing nutrient-use efficiency in rice cropping systems: the next generation of technology

Rice production must increase dramatically to meet the demand projected for 2025. If the technologies that affect nutrient utilization by the rice crop remain unchanged, that production increase will require almost 300% more than the present application rate of N alone in irrigated environments. This is an undesirable amount economically and environmentally. The nutrient-use efficiency of rice cropping systems must be improved, along with yield potential of rice cultivars, in order to improve profitability of rice production and prevent environmental degradation in irrigated areas. Part of the projected demand for rice will be met through production increases in rainfed environments, where yields need to double from their present average of 2.0 t ha(-1). The productivity of these systems is governed by interactions between water availability and the nutritional status of the crop. Cultivar improvement for tolerance to abiotic stress must be combined with management approaches that improve nutrient-use efficiency in such rainfed environments. (C) 1998 Elsevier Science B.V.