HERBICIDE TREATMENT EFFECTS ON PROPERTIES OF MOUNTAIN BIG SAGEBRUSH SOILS AFTER 14 YEARS

Soil properties under stands of vegetation dominated by mountain big sagebrush (Artemisia tridentata ssp. vaseyana) and grass were examined 14 yr after spraying with 2,4-dichlorophenoxy acetic acid (2,4-D) to control sagebrush. Changes in only a few soil chemical properties were found after conversion to grassland. Phosphorus and K were apparently redistributed from depth to the surface 5 cm of soil by grass-dominated vegetation. No changes attributable to vegetation conversion were found for total C, Na, Mg, cation exchange capacity, base saturation, pH, bulk density, or potential net N mineralization rates at any depth. Essentially, control of big sagebrush, in the absence of grazing, had no effect on site fertility.