Optimum Windbreak Spacing in Great Plains Agriculture

Integer programming techniques were used to determine the optimal windbreak pattern for corn and soybean production over a 70-year planning horizon. Field windbreaks provide numerous benefits to agricultural producers, including increased crop yields, erosion control, and wildlife habitat. However, windbreaks involve costs of establishment, maintenance, removal, localized yield reductions, and a loss of income resulting from cropland dedicated to windbreaks. As with any farm investment, windbreaks must be economically viable if they are to be adopted by producers. In addition to the direct costs of establishment, maintenance, and removal, yield increases must be large enough to replace opportunity costs of yield losses due to cropland removed from production and yield reductions in the area immediately adjacent to the windbreak. The economic viability of windbreaks is examined here by comparing the yield benefits resulting from climatic protection to total costs. A key question in determining economic viability is how closely windbreaks should be spaced. Assuming a conservative growth rate and tree height (20 feet in 40 years), the optimal spacing was approximately 386 feet, or 13 times the height of the windbreak. The net return results for the optimum pattern were 7.61 % and 9.23% over unprotected production for corn and soybeans, respectively, assuming windbreak maturity is reached at 40 years. Net returns increased as the time required for windbreaks to reach maturity decreased. For taller windbreaks, the optimal spacing remains at 13 times windbreak height, but the absolute distance between windbreaks increases and the number of windbreaks required for optimal protection decreases