摘要：Multiple studies have estimated factors influencing cover crop adoption which include control weed population (Ngouajio et al. 2002), increased soil health (Santhi Wicks and Richard Howitt, 2005), and increased productivity (Johannes M. S. Scholberg, Santiago Dogliotti, Lincoln Zotarelli, Corey M. Cherr, Carolina Leoni and Walter A. H. Rossing, 2010, Jason Bergtold, Jason Fewella, and Patricia Duffy, 2010). An externality of adoption of cover crops that has not been explored is its potential impact on the amount of nitrogen use by farmers. Using a 2009 survey of conventional and organic corn farmers in 7 states of the US, we estimate the factors affecting adoption of cover crops and its impact on nitrogen use. While nitrogen used by farmers is considered as left censored variable, adoption of cover crop is considered as an endogenous dummy variable. The resulting system is a two stage Limited Dependent Variable (LDV) model defined by the amount of nitrogen used by farmers, with endogenous dummy variable that investigates whether the farmer adopts cover crops. We conclude that farmers adopting cover crop technologies, that increase production efficiency, tend to decrease nitrogen fertilizer use. Further, this decrease is significantly higher among organic corn producers compared to conventional corn farmers.
关键词：Cover Crop Adoption;Nitrogen Management;Limited Dependent Endogenous Variable Model
