POLICY IMPLICATIONS OF RANKING DISTRIBUTIONS OF NITRATE RUNOFF AND LEACHING FROM CORN PRODUCTION BY REGION AND SOIL PRODUCTIVITY

The purpose of this study was to understand the implications of farm-t o-farm and regional variations in N runoff and leaching for targeting specific policies to reduce nutrient contamination. To do this, we est imated distributions of nitrate runoff and teaching for individual soi ls on nearly 150 farms in three farm production regions of New York an d ranked the distributions according to second degree stochastic domin ance criteria (SSD). Based on these rankings, it was evident that crop land across farms and regions of New York is so heterogeneous that it is impossible to target policies to reduce nitrate contamination based on farm or regional characteristics. A much clearer ranking was found when soils were grouped by productivity group as measured by corn (Ze a mays L.) yield. Based on the estimated elasticities of nitrate runof f and leaching with respect to N application, one can target those are as where contamination problems are most severe by focusing on soils w ith potential yields greater than 125 bu/acre. For it to make sense to target lower productivity soils, the productivity of additional N app lication at the margin on the highest yielding soils would have to be about double that of the lower yielding group. Evidence indicates that the ratios of productivities are less than unity in all three product ion regions.