Daily decisions of actions in cotton production management involve the question how much increase in net return would result if the particular proposed action were implemented. Crop simulation offers a way to quantify the benefit.

Transfer of crop simulation to the cotton farm was implemented by placing a personal computer and a user oriented version of GOSSYM on two cooperating farms in 1984. Fertilization and irrigation decisions were aided by the model. Farmer reaction was positive.

The farmers focused or yield-determining attributes of the crop system. Differences in crop performance due to hypothesized actions are important, not absolute performance per se. Personal computers and crop simulation software were very valid media for transferring to the farm basic research findings. The inclusion of crop simulation in expert systems for use in answering questions in cotton production is obvious.