Estimation of Red Soil Runoff Using Monte Carlo Simulation for Preliminary Evaluation of Support for Red Soil Runoff Prevention Measures under the Condition of Insufficient Information

We got hold of the situation of red soil runoff prediction measures (RSRPM) and farmers' willingness to introduce RSRPM by the questionnaire survey and calculated the amount of red soil runoff (RSR) and the cost of the RSRPM using Monte Carlo (MC) simulation. As the results, the following was recognized. (1)The difference of the subsidy system of the RSRPM influenced the introduction of the RSRPM. Mulching and green-belt were popular for farmers. (2)Farmers' willingness to introduce the RSRPM was more than 90% in the case of the 100% subsidy and decreased in the case of the 50% and 0% subsidy. Farmers who did not have the willingness to introduce the RSRPM in the case of 100% subsidy did not have it in the case of 150% subsidy. (3) There were not differences of the change of the willingness according to the subsidy ratio between two villages. (4) The estimated value of RSR had variance under the condition of the insufficient information and the stochastic grasp of RSR by the MC simulation was effective. (5)There was not the clear relationship between the cost of the RSRPM and the estimated RSR value, but there was the pareto relationship between these values and MC simulation was effective for the preliminary planning evaluation considering the cost-effectiveness.