Dispelling misperceptions regarding variable rate application

Economic principles drive producers' variable and uniform rate nitrogen (N) application decisions. Output price, N price, N application cost, soil productivity and spatial variability of soil types determine the optimal application rates and therefore technologies. Variable rate application may lead to greater N application on less productive soils and increased overall farm N usage; it also may be economically superior to use uniform rate, even with modest spatial variability or soil productivity differences. These findings have implications on economic evaluation, policy making and environmental considerations that extend beyond this example of nitrogen on corn production and may be generalized to other crops and inputs.