• Effects of Sulfur Fertilization on Productivity and Botanical Composition of California Annual Grassland

      Caldwell, R. M.; Menke, J. W.; Duncan, D. A. (Society for Range Management, 1985-03-01)
      Changes in botanical composition and productivity of total herbage and 14 categories of annual range plants caused by elemental sulfur fertilization, range site, and precipitation were studied. Total herbage production on the wetter and more fertile swale sites was not affected by sulfur fertilization, but production on adjacent open upland and rocky, brushy upland sites usually increased with added S. Herbage production increased 28% or 1,400 kg/ha on fertilized open upland sites and 51% or 1,800 kg/ha on fertilized rocky, brushy upland sites during the wettest year sampled. Over the 3 years sampled, the most desirable grass, soft chess, averaged 68, 22, and 66% higher production (438, 287, and 388 kg/ha increases, respectively) on fertilized versus control range units for swale, open upland, and rocky, brushy upland range sites, respectively. Likewise, the less desirable but important early-forage species, ripgut brome, increased 164% or 544 kg/ha on swales and 205% or 437 kg/ha on rocky, brushy uplands with fertilization; only a 16% increase or 98 kg/ha occurred on open upland sites. Grass responses were offset by decreased forb production, while the proportion of legumes remained nearly the same. Upland sites benefited from sulfur fertilization by exhibiting both increased clover and other legume production in the wettest year. Filaree was unaffected by sulfur fertilization.