An adventure in applied science - IRRI books - International Rice ...

180 History of the International Rice Research InstituteBeginning in 1974, IRRI scientists (agricultural economists, agronomists,and statisticians) undertook a yield constraints project to study the basicreasons for the yields gaps just described. As a first step, they worked outmethodologies 1 for measuring the biological and socioeconomic restraints.Next, IRRI invited cooperating scientists from six countries to a workshopto create an International Rice Agroeconomic Network (IRAEN). By early1975, the group had produced the design of the experiments and set theprocedures for studying the factors constraining rice yields in farmers' fields.The results of these coordinated studies in the Philippines, Indonesia,Thailand, Taiwan, Bangladesh, and Sri Lanka have been published in twovolumes. The first, Constraints to High Yields on Asian Rice Farms: an InterimReport, was published in 1977 and a final volume, Farm-level Constraints to HighRice Yields in Asia: 1974-77, appeared in 1979.Since 1977, studies of constraints — conducted jointly by IRRI’s Departmentsof Agricultural Economics, Agronomy, and Irrigation Water Management— have been continued in the Philippines.Many important conclusions have been derived from both the investigationsby the network scientists and the more detailed work in the Philippines,but only a few of them can be mentioned here. Perhaps the most uniformconclusions reached from the various environments under study were thefollowing:• The yield gap between what the farmers obtained and what resultedfrom a high level of management on the same farms was usually greaterin the dry season than in the wet;• Fertilizer response was always higher in the dry season than in the wet,provided of course that there was sufficient irrigation water in the dryseason; and• Among the three inputs — fertilizer, insect control, and weed control —the most uniform and largest response was from fertilizer, the secondfrom insect control, and the lowest from weed control.Somewhat regrettably (considering its vital role), water management wasnot a variable studied in this project. Although in the study sites selected, eitherpump or canal irrigation was obtainable, mention nevertheless was made thatat several sites, reliable interpretations of yield data were impossible becauseof inadequate water supply. Realizing that around the world water control isthe single most important factor affecting the yield of wetland rice, IRRI since1980 has included that factor as a variable.One of the key aspects of the constraints study is that it brought togethereconomists, agronomists, and statisticians from six countries to work on acommon project.Agricultural engineering and the International Agricultural Machinery Network( IAMN ). In 1972, there were three senior scientists in the Agricultural Engi-1The methodology part of this study was published by IRRI in 1978 in a booklet entitled AHandbook on the Methodology for an Integrated Experiment-Survey on Rice Yield Constraints, by DeDatta, Gomez, Herdt, and Barker.