Fig. 6. Digestible dry matter production per dollar (U.S. $) irrigation water invested as influenced by irrigation levels of low, medium, and high, and averaged across Bothriochloa caucasica, B. ischaemum, and B. bladhii. Data were also averaged across years 2002 and 2003. Means with the same letter within one water treatment are not different (P > 0.05).