Economics of Gypsum and Elemental Sulfur as Fertilizers on Subclover-Grass Pastures in Northern California

Abstract

Sulfur deficiencies are widespread on the rangeland soils of California and the application of sulfur-bearing fertilizers has been widely recognized as a promising range improvement on these soils. Considerable work has been done on the management and ecological aspects of sulfur fertilization of California rangeland; however, little or no economic analysis of this improvement exists. Using existing data from subclover-grass pastures in northern California to derive aggregate production functions, optimal application rates of sulfur applied as elemental sulfur and gypsum were determined using standard marginal analysis. Both elemental sulfur and gypsum proved to be profitable means of increasing both winter and total yearly production when either harvested hay or grazed forage (AUM's) were considered as products. Using 1981 material costs and product prices applied to total yearly hay production, the optimum rate of sulfur applied as gypsum with 3 years residual was 251 kg/ha for an increased profit of $101/ha/yr over unfertilized pastures. The optimum rate of elemental sulfur was 147 kg/ha for a profit increases of $93/ha/yr. When total yearly grazed forage was considered the product, optimum application rates were 195 kg/ha of sulfur as gypsum and 126 kg/ha for elemental sulfur yielding profit increases of $46/ha/yr and $48/ha/yr, respectively. Optimal application rates and profits were lower for both hay production and grazed forage when winter production was optimized.