Abstract:

The objective of this research was to investigate brew sorghum’s role in water requirements and water use efficiency under different irrigation conditions, a field experiment was conducted to investigate the effects of different irrigation amounts on sorghum [Sorghum bicolor (L.) Moench] growth, yield and water use efficiency in a drip irrigation system. The experiment was design the randomized complete block with three replications. The irrigation amounts were determined by the evaporation from a standard 20-cm diameter pan placed above sorghum canopy. Four irrigation amounts (no irrigation as control, 30% of water evaporation quantity on 20-cm evaporating pan, 60% of evaporation quantity and 90% of evaporation quantity) were employed. The results showed that, sorghum plant tall, stem thick and leaf area of the 90% of evaporation quantity treatment were significant higher than control treatment at the flowering stage. The sorghum biomass of the 90% of evaporation quantity treatment were increased by 9.19%, 20.92% and17.27%, and the grain yield was also increased by 8.99%, 16.89% and 19.74% respectively, as compared to the treatments of 60% evaporation quantity, 30% evaporation quantity and control. The 1000-grain weight of the 90% of evaporation quantity treatment were enhanced by 14.71%, 10.20% and 7.89% respectively, compared to the treatments of 60% evaporation quantity, 30% evaporation quantity and control. The peak value of average daily consumed water quantity was appeared at the period from larger horn stage to flowering stage. The water requirement of sorghum was in the range of 400-590 mm. As the quantity of irrigation water increases, the amount of water consumed and grain yield of sorghum were increased, whereas, the water use efficiency showed a declining trend. Compared to control treatment, the water use efficiency of the 90% of evaporation quantity, 60% of evaporation quantity and 30% of evaporation quantity was declined by 17.3%, 17.3% and 11.1%, respectively.