Recently, discussion had reemerged over the value of integrated pest and crop management training, through intensive approaches such as farmer field schools or participatory training, as a development approach (Feder et al, 2004). This paper develops a model of human capital accumulation through participatory research and tests several hypotheses on the effectiveness of this approach to increase the adoption of soil conservation and fertility management innovations and improve farm productivity in southeast Asia. Bivariate Probit models with treatment effects are estimated using full information maximum likelihood (Evans and Schwab, 1995: Trost and Lee, 1984) and covariates related to changes in land allocation and productivity, measured before project and after project intervention, are investigates. We follow Greene (1998) to control for simultaneity between adoption and impact by using the predicted adoption decision from the second set of regressions to calculate productivity differentials. Overall, we find that treatment affects associated with the participatory research activities are significant and positive in explaining the differential adoption rates of intercropping, hedgerows, contour ridging, the usage of farm yard manure and chemical fertilizer. The positive relationship between the adoption of soil conservation and fertility management techniques and participation, given very limited productivity impact, may indicated the "value" of the participatory approach to illustrate the social costs of land degradation, sensitize participants towards internalizing these costs, and demonstrate the importance of long-run strategies to preserve land productivity, or both. Secondly, we find that there are additional benefits to participatory research activities that are not embodied in the adoption of soil conservation or fertility management techniques.