A site-specific nutrient management (SSNM) research project was started in Thailand in 1997 by Professor Dr. Tasnee Attanandana and colleagues. The project focused on a lowcost technology with high efficiency and the protocols that can easily be followed by farmers. Soil classification was prepared in a simple way so that Thai farmers can identify their own soil. A soil test kit has been invented which allows farmers to analyze soil nutrients (NPK) by themselves. DSSAT and PDSS models were used to generate nitrogen (N) and phosphorus (P) requirements, and a specific model for potassium (K) requirement was developed. Nutrient requirement data from crop modeling was processed by simple formulas to generate fertilizer recommendation that provides the highest return under specific conditions. After the experimental trials, the project led to the steps of technology transferring and programming of SSNM for maize (SimCorn) in 2001. After the success of SSNM for maize, in 2005, the project expanded into SSNM for rice (SimRice) and sugarcane (SimCane). During this time, the project emphasized the independency of farmers. In 2008, the Land Development Department generated the Onfarm program following the policy of the Ministry of Agriculture and Cooperatives. The Onfarm program used the data from the SSNM projects together with the fertilizer recommendation based on soil test by the Department of Agriculture. As a result, the Onfarm program recommended fertilizers for major crops in Thailand. At present, a new research team is conducting the SSNM for chili.