技術特定型環境支援における経済評価の方法: さとうきび栽培における赤土流出問題を事例として

This research firstly analyze theoretically the efficiency of the technique oriented environmental payment, hiring a certain countermeasure technique is subsidized, to the polluter. We reveal that if the polluter type relative to the opportunity cost and the amount of pollution reduction of a technique is hidden information, environmental payment above will fail to attain the socially optimal technique choice for all polluter in some case. Secondly, using additive DEA, we verify the 36 sugarcane farmers' individually and socially rationality in choosing the countermeasure technique for red clay outflow from their farmland in Okinawa, Japan. We find that 1) green manure crop/cover crop and ratoon sugarcane cultivation practice have been already established as a basic techniqe from the managerial point of view in consolidated farmlands in a flat area, 2) for majority of farmers, ratoon sugarcane cultivation practice is preferable to green manure crop/cover crop from the social point of view, 3) in the study area, there is no feasible solution to make all type of farmers choose socially optimal technique through the technique oriented environmental payment. It is recommended that the payment for the green manure crop/cover crop in consolidated farmlands in a flat area should be expired as a normative technique in the survey area in order to reduce the adverse technique selection by farmer like not to choose ratoon sugarcane cultivation practice but green manure crop/cover crop.