Nutrient management for improving lowland rice productivity and sustainability

Rice (Oryza sativa L.) is an important food crop for a large proportion of the world's population. Total rice production will need to increase to feed an increasing world population. Rice is produced under both upland and lowland ecosystems with about 76% of the global rice produced from irrigated-lowland rice systems. The anaerobic soil environment created by flood-irrigation of lowland rice creates a unique and challenging environment for the efficient management of soil and fertilizer nutrients. Supplying essential nutrients in adequate rates, sources, application methods, and application times are important factors that influence the productivity and sustainability of rice. This review emphasizes our current, research-based knowledge of N, P, K, Ca, Mg, S, B, Fe, Mn, and Zn management in regards to the efficiency and sustainability of lowland rice production and identifies where additional research is needed to bridge information gaps. Our goal is to provide a comprehensive review describing the nutritional problems, nutrient use efficiencies, and the production strategies used for efficient nutrient use and production of lowland rice. While the soils, climatic environments, cultivars, and degree of mechanization may vary considerably among the rice producing regions of the world, the basic principles governing efficient nutrient use by flood-irrigated rice are relatively constant. A summation of best management practices should help scientists develop practical, integrated recommendations that improve nutrient use efficiency in lowland rice production systems. © 2003 Elsevier Science B.V. All rights reserved.