Soil Properties in Creosotebush Communities and their Relative Effects on the Growth of Seeded Range Grasses

Abstract

AbstractSoils were collected to 15 cm along the four cardinal directions at three locations around 10 creosotebush [Larrea tridentata (DC.) Cov.] plants at five sites in the southwestern United States. The sampling locations were: (i) at the canopy center, (ii) along the outer canopy edge, and (iii) in open areas between plant canopies. A portion of the soil from each sampling location was analyzed for particle size distribution, pH, EC, CaCO3, Ca, K, Na, Mg, NO‐3‐N, organic C, available P, and Mn. The remaining soil from each sampling location was seeded with either Lehmann lovegrass (Eragrostis lehmanniana Nees) or blue panicgrass (Panicum antidotale Retz.). Grass seeds were germinated and grown for 42 d in a greenhouse. Nitrate was significantly (∝ = 0.05) lower in open areas between creosotebush canopies than near the shrub canopy center at all sites. Grass seedling growth decreased as the distance from the canopy center increased and seedling growth was highly correlated with nitrate concentrations. Spatial distribution patterns for the other measured soil properties did not occur in a consistent fashion across all sampled sites. The action of mechanical tillage to limit creosotebush competition, and corresponding dilution of NO‐3‐N in the soil volume, may reduce the probability of establishing perennial grasses.