SEQUENTIAL ADOPTION OF SITE-SPECIFIC TECHNOLOGIES AND ITS IMPLICATIONS FOR NITROGEN PRODUCTIVITY: A DOUBLE SELECTIVITY MODEL

This paper analyzes the sequential decision to adopt two site-specific technologies, soil testing and variable rate technology (VRT), and their impact on nitrogen productivity in four Midwestern states. The results indicate that while farm location was a key variable influencing the adoption of soil testing, human capital and innovativeness of farmers had a significant impact on the adoption of VRT. A double selectivity model applied to correct for sample selection bias shows that gains in nitrogen productivity due to the two adoption decisions are largest for farms with below average soil quality and statistically insignificant for farms with above average soil quality. These findings have implications for the targeting of public policies designed to promote adoption to reduce nitrate pollution.