The response of forage sorghum [Sorghum bicolor (L.) Moench] to three
irrigation treatments in a semiarid environment was studied in the fie
ld for two seasons. Treatments were light frequent, moderate less freq
uent, and heavy infrequent irrigation, where irrigation water at 8 mm
day(-1) was delivered every 7, 10, and 13 days, respectively. These ir
rigation regimes meant heavier water inputs with increasing irrigation
frequency. Plant heights and leaf area indices of forage sorghum were
higher in the frequently watered plots than in plots where irrigation
water was delivered less frequently. Averaged over the two seasons, m
aximum dry matter (DM) yields were 16.3, 11.8, and 10.5 tonnes ha(-1)
for frequent, intermediate, and infrequent irrigation regimes, respect
ively. Light, frequent irrigation resulted in a significantly higher w
ater use efficiency (WUE) compared to the other two regimes, thus incr
easing the return from irrigation. These results suggest that in such
semiarid environments, DM yields and WUE of forage sorghum could be in
creased by combining light irrigation with a short interval.