Competition between Schizachyrium scoparium and Prosopis glandulosa

A competition experiment was carried out in a greenhouse with Schizachyrium scoparium (Michx.) Nash (little bluestem) and seedlings of Prosopis glandulosa Torr. (honey mesquite). The effect of S. scoparium density on the growth of P. glandulosa and the effect of a single P. glandulosa seedling on the growth of various densities of S. scoparium were examined. When P. glandulosa was grown with S. scoparium, there was a significant decrease in P glandulosa above-, belowground, and total dry weight at all S. scoparium densities tested. In contrast, P. glandulosa did not cause a significant reduction in S. scoparium dry weight. Root: shoot ratios for both P glandulosa and S scoparium increased almost three times from lowest to highest grass density. The number and length of flowering stalks of S scoparium per plant decreased with increasing density. The presence of P glandulosa caused a slight nonsignificant reduction of the number and length of S. scoparium flowering stalks. Establishment of P. glandulosa and other woody legumes would probably be low in high glass density and highly productive grasslands.