TOWARD INCREASING NUTRIENT-USE EFFICIENCY IN RICE CROPPING SYSTEMS - THE NEXT-GENERATION OF TECHNOLOGY

Rice production must increase dramatically to meet the demand projecte d for 2025. If the technologies that affect nutrient utilization by th e rice crop remain unchanged, that production increase will require al most 300% more than the present application rate of N alone in irrigat ed environments. This is an undesirable amount economically and enviro nmentally. The nutrient-use efficiency of rice cropping systems must b e improved, along with yield potential of rice cultivars, in order to improve profitability of rice production and prevent environmental deg radation in irrigated areas. Part of the projected demand for rice wil l be met through production increases in rainfed environments, where y ields need to double from their present average of 2.0 t ha(-1). The p roductivity of these systems is governed by interactions between water availability and the nutritional status of the crop. Cultivar improve ment for tolerance to abiotic stress must be combined with management approaches that improve nutrient-use efficiency in such rainfed enviro nments. (C) 1998 Elsevier Science B.V.