Edaphic Factors Influencing the Control of Wyoming Big Sagebrush and Seedling Establishment of Crested Wheatgrass

Abstract

The physiographic position and taxonomic identity of soils of a Wyoming big sagebrush (Artemisia tridentata spp. wyomingensis)/grassland community were determined. Surface soil materials from each identified soil were analyzed for a variety of chemical and physical properties. Areas of each soil were either burned, sprayed with 2,4-D [(2,4-dichlorophenoxy) acetic acid], or plowed for sagebrush control and seeded to crested wheatgrass (Agropyron desertorum cultivar Nordan). Spraying and plowing resulted in significantly (p=0.05) different sagebrush mortalities of 75 and 62% averaged over all soils with brush mortality being much higher on some soils than others. Burning resulted in 100% sagebrush mortality on all soils. Seedling establishment of crested wheatgrass was significantly higher on plowed than sprayed soils with 9 and 6 seedlings per meter of row, respectively. Soils of burned areas averaged 5 seedlings per meter of row on a dry year. Most seedlings were established on loamy soils regardless of the method of brush control. Multiple regression analyses of edaphic factors were used to develop equations predicting brush mortality and seedling establishment in sprayed and plowed areas. Soil series descriptions include data which could be used in making such predictions.