Range Plant Yield and Species Relationships in Natural and Partially Controlled Environments

Abstract

Competition and herbage production studies were established on soil columns (1.2 m square) that were isolated from the surrounding soil by heavy plastic sheeting to a depth of 1.4 m. Some plots received only natural precipitation; some 1-1/2 times the growing-season precipitation, and some 2/3 the growing-season precipitation. These different moisture levels had no significant effect on herbage yields during the 3-year period. Plots of alfalfa yielded most. Plots containing Kochia yielded as much as those containing alfalfa the first year, but not thereafter. Crested wheatgrass consistently outyielded Russian wildrye. Adjacent natural field plantings of the same species provided evidence that both alfalfa and Kochia had roots below the plastic barrier and were obtaining moisture from adjacent soil. Alfalfa was least affected and Kochia most affected by a close (5-cm) harvest height.