Production and water use efficiency of three old world bluestems

Abstract

Information on water use efficiency (WUE) of forage grasses is needed to select appropriate species for improved productivity in semi-arid environments. Three old world bluestem species - [Bothriochloa bladhii (Retz) S.T. Blake 'WW-B. Dahl'], [Bothriochloa ischaemum (L.) Keng. var. ischaemum (Hack.) 'WW-Spar'], and [Bothriochloa caucasica (Trin.) C.E. Hubbard 'Caucasian'] - were surface drip-irrigated with zero (dryland) and low, medium, and high levels to determine dry matter (DM) yield and WUE in 2001, 2002, and 2003 in Lubbock, TX. Water applied in the high irrigation level equaled 100% of grass reference evapotranspiration (ETo); low and medium levels were calculated as 33 and 66% of irrigation applied in the high level; the dryland treatment received no irrigation. Maximum DM yield was obtained with B. caucasica under high irrigation (18.0 Mg ha-1) vs. B. bladhii (15.2 Mg ha-1) and B. ischaemum (12.6 Mg ha-1) averaged over all years. The WUE of B. caucasica under low, medium, and high irrigation was higher than B. ischaemum in 2001 (P < 0.05), and B. ischaemum and B. bladhii in 2003. Maximum and minimum WUE of all treatment combinations and years were 24 and 6 kg DM ha -1 mm-1 in B. caucasica with low irrigation and B. bladhii under dryland, respectively. Results showed that differences exist in WUE among species of Bothriochloa under irrigation. On the basis of WUE and potential DM yield, B. caucasica may be better suited for forage production in the Texas High Plains than either B. bladhii or B. ischaemum. © Crop Science Society of America.