Sulfur or Sulfur Plus Nitrogen Increases Beef Production on California Annual Range

Abstract

A 6-year study was conducted to evaluate the response of California annual range to triennial applications of sulfur only and sulfur plus nitrogen fertilizer. Range response was evahtated in terms of length of the green season, steer weight gain, total beef production and steer days of grazing/ha. Neither fertilization treatment consistently lengthened the green season nor infhtenced steer weight gain compared to nonfertilized range. Steer days of grazing and total beef production/ha were greatest on sulfur plus nitrogen-treated range, intermediate on sulfur only-fertilized range and least on nonfertilized range. Sulfur only-fertilized range increased beef production about 60 kg/ha compared to nonfertilized range, and range fertilized with sulfur plus nitrogen increased beef production nearly 50 kg/ha more than sulfur onlyfertilized range. On California’s annual range, most of the herbage is produced between early February and mid-April, when soil moisture is generally abundant and rising temperatures foster rapid plant growth. Forage selected by cattle during this time of the year is well balanced nutritionally and produces the most rapid animal weight gains. However, as annual herbage matures and dries, generally during mid-June, the rate of animal weight gain drops rapidly. Wagnon et al. (1958) found that without supplements, weaner and yearling steers gained weight only during the green season; they maintained weight through the dry-forage season and lost weight during the winter season. Conrad (1950) and Martin (1958) reported a widespread sulfur deficiency in several soils derived from a wide variety of parent materials at many locations throughout California. Bentley (1946) found that pit-run gypsum increased herbage production on the San Joaquin Experimental Range. Fertilization with sulfur every third year increased annual herbage yields, grazing capacities (Bentley et al. 1958), and steer gains (Wagnon et al. 1958) over those on nonfertilized range. Bentley and Green (1954) noted the first marked response to sulfur fertilization was a stimulation of legume growth. Grass production increased the year after stimulation of legumes and the beneficial effects held over for a few years after sulfur fertilization. Martin (1958) reported that soil nitrogen deficiency was at least as widespread in California as sulfur deficiency. The first year after treatment, cattle weight gains were greater on nitrogen-fertilized range than on nonfertilized range, but less than where both nitrogen and sulfur had been provided (Martin and Berry 1970). Similar though reduced responses were reported the second year after treatment. Triennial applications of sulfur or sulfur plus nitrogen increased herbage yields and grazing capacity of annual ranges (Conrad et al. 1966). Woolfolk and Duncan (1962) reported that herbage production, grazing use, and animal weight gain were greatest on annual range fertilized with sulfur and nitrogen. Fertilization with sulfur alone was less beneficial. Benefits of range fertilization included earlier range readiness, increased herbage production, and increased herbage protein content (McKell et al.