To develop and test methodology for identifying and explaining the gap between the yields obtained by the farmers and those obtained by the researchers at the same sites in Iloilo Province in the Philippines; To develop and apply procedures for identifying the physical factors that influence the adoption and efficient use of technological innovations designed to increase rice yields at farm level; To determine the economics of alternative input levels and practices. A management package concept was used to determine optimum package for maximum economic benefits to the farmers.

There is a sizeable yield gap between research and average farm yields in all rice-growing countries worldwide, with key constraints ranging from biophysical to socio-economic issues. This manual provides guidelines for the identification of biophysical constraints and suggests measures that could be taken to help boost yields in rice production.