Grass Species Adaptability in the Southern High Plains: A 36-Year Assessment

Abstract

A 36-yr old species adaptation test was evaluated and the relative quality of some persisting native and introduced grass species was determined. The site was Conlen loam on the Rita Blanca National Crasshntd in Dallam County, Texas. Of the 25 species planted, only yellow bluestem (Bothriochloa ischaemum),l Caucasian bluestem (Bothriochloa caucasica), and galleta (Hilaria jamesii) tended to dominate the plots on which they were originally planted. Yellow and Caucasian bluestem had spread into plots phmted to other grasses but galleta had spread very little. Yellow bluestem was as high or higher in protein, mineral content, and digestibility (IVDMD) than the other grasses analyzed [Caucasian bluestem, galleta, sideoats grama (Bouteloua curtipendula), blue grama (Bouteloua grads), and western wheatgrass (Agropyron smithii)]. The contents of Caucasian bluestem and galleta were not signlflcantly different from those of yellow bluestem, except that galleta was lower in IVDMD, especially when mature. These 3 grasses merit consideration in range seeding programs on Conlen and similar soils in the Southern High Plains. For many years, there has been a continuing search for grasses that will increase the productivity of rangelands. Both introduced species and improved selections of native species have been investigated. On the Southern High Plains, there have been some successes with introduced species but when prolonged droughts occur, the introduced species are often replaced by annual weeds, native grasses, or persistant introduced grasses from adjacent or nearby plots. Sites of adaptation studies are often destroyed after the selections are rated and little attention is given to plants that may have invaded the test species. Although comparatively short-term adaptation studies are valuable for cursory evaluation of species, they do not evaluate long-term persistance, indicate aggressiveness of species in invading other species, nor indicate species which may become prevalent where a test species has failed. Authors are soil scientist, USDA-ARS, Conservation and Production Research Laboratory, Bushland, Texas 79012; range scientist, USDA-ARS, Southern Plains Range Research Station, Woodward, Okla. 73801. This article is a contribution from USDA, Agricultural Research Service, P.O. Drawer 10, Bushland, Texas 79012.