Vegetation‐Soil Relationships on Thin or Shallow Range Sites in Western South Dakota

Abstract

AbstractLittle bluestem (Schizachyrium scoparium [Michx.] Nash) and/or big bluestem (Andropogon gerardii Vitman) stands often occur adjacent to western wheatgrass (Agropyron smithii Rydb.) stands on thin or shallow range sites and closely related sites. The purpose of this study was to identify soil properties that cause the nonrandom distribution of the grasses. Particle size, pH, organic matter, total N, total PO4, and available PO4‐P were determined on 17 soil profiles that supported different grass distributions. Soils with western wheatgrass had more plant‐available PO4‐P than soils with bluestem, but usually less organic matter. Western wheatgrass needs a large supply of available PO4‐P because it grows rapidly in the spring. The bluestems grow when temperatures are higher and the microbial‐chemical release of plant nutrients is greatest. The distribution of the grasses is related to soil properties that in turn, are perpetuated by bluestems supplying more organic matter to the soil surface layer that western wheatgrass. Sideoats grama (Bouteloua curtipendula [Michx.]) can grow under conditions intermediate to those suited for bluestems and western wheatgrass.