Water Use by Forage Species¹

Abstract

Abstract Forage production on the High Plains of Western United States might be done more economically if research provided more water‐use information for species. A study was made to determine (1) water‐use efficiency and (2) ability to use available soil water during a harvest growing period. Forages common to the area were evaluated in both greenhouse and field environments. The legume species evaluated were ‘Alsike’ clover ( Trifolium hybridum ), ‘Dawson’, ‘Fremont’, ‘Ladak’, ‘Team’, ‘Travois’, and ‘Vernal’ alfalfa ( Medicago sativa L.), ‘Lutana’ cicer milkvetch ( Astragalus cicer L.), and ‘Remont’ sainfoin ( Onobrychis vicaefolia Scop.). Pasture grasses evaluated were ‘Fawn’ tall fescue ( Festuca arundinacea Schreb.), Garrison creeping foxtail ( Alopecurus arundinaceus Poir), ‘Latar’ orchardgrass ( Dactylis glomerata L.), ‘Grennar’ intermediate wheatgrass [ Agropyron intermedium (Host) Beauv. L.], thickspike wheatgrass [ A. dasystachyum (Hook) Scribn.] and ‘Regar’ bromegrass ( Bromus biebersteinii Roem & Schult.); while range grasses were blue grama [ Bouteloua gracilis (H.B.K.) Lag], crested wheatgrass [ Agropyron desertorum (Fisch. ex Link) Schult.], slender wheatgrass [ A. trachycaulum (Link) Malte], western wheatgrass ( A. smithii Rydb.), and green needlegrass ( Stipa viridula Trin.). The study was made on Altvan soil, a fine, sandy, clay loam belonging to the mixed mesic family of aridic arguistolls. Water use was monitored by gravimetric method and by tensiometers in the first and second studies, respectively. Transpiration in the greenhouse during a crop growing period ranged from 7.2 cm for the milkvetch to 15.5 cm for Regar bromegrass. Blue grama had the highest water‐use efficiency of all species but was able to utilize only a relatively small amount of the available water in forage production. Growing the plants in a field environment increased evapotranspiration by 100 to 200% compared with that in the greenhouse. Thickspike wheatgrass appeared to be capable of adapting to either a semiarid or humid climate but range grasses studied were unable to use large amounts of available water.