Site-Specific Nutrient Management (SSNM): An Approach for Optimizing Nutrient Use in Rice Production.
Mirasol F. Pampolino1, Christian Witt2, and Roland J. Buresh1. (1) IRRI, DAPO Box 7777, Metro Manila, Philippines, (2) PPI/PPIC and IPI, 126 Watten Estate Rd, Singapore, 287599, Singapore
Site-specific nutrient management (SSNM) is a low-tech, plant-based approach for managing the nutrient requirements of rice. The SSNM approach provides principles and tools for supplying rice with nutrients as and when needed to achieve high yields while optimizing use of nutrients from indigenous sources. The SSNM approach involves three steps. The first step is to establish an attainable yield target, which is location and season-specific depending upon climate, rice cultivar, and crop management. The yield target reflects the total amount of nutrients that must be taken up by the crop. The second step is to ensure effective use of existing nutrients such as from soil, organic amendments, crop residue, manure, and irrigation water. The third step is to apply fertilizer to fill the deficit between crop needs and indigenous supply and to maintain soil fertility. The SSNM concept for rice was developed in the mid-1990s. It was then evaluated and refined in about 200 irrigated rice farms in Asia through partnerships with national agricultural research and extension systems. In the last five years, the initial SSNM concept was simplified to provide farmers and extension workers with easy-to-follow tools and guidelines for applying N, P, and K fertilizers. The SSNM approach is now being widely promoted through expanded partnerships with research and extension organizations, nongovernment organizations, and the private sector. A web site on SSNM (www.irri.org/irrc/ssnm) features the principles for making N, P, and K recommendations, local recommendations developed for major rice-growing areas, tools and techniques for implementing SSNM (such as the leaf color chart, nutrient omission plot technique, zinc addition plot technique, and software), publications, and training materials.