Drip Watering Regimes on Growth Performance, Yield, and Water Use Efficiency of Sorghum in Semi-arid Environment of Tanzania: Effects

Abstract

The inadequacy of water for crop production due to low and unreliable rainfall is the characteristic of dryland areas, including Tanzania, whose more than 60% of its arable land is prone to drought and has high frequencies of crop failure. In enhancing climate change resilience for crop production in these areas, field trials were conducted in the semi-arid environment of central Tanzania to assess the effectiveness of three drip watering regimes on the growth performance, grain yield, and water use efficiency (WUE) of sorghum. The irrigation treatments, irrigating early in the morning (EM), late in the evening (LE), and both early in the morning and late in the evening (ELE), were replicated thrice in a randomized complete block design for the two seasons. The results showed that sorghumgrain yield and growth parameters were significantly higher (p <0.05) by almost two-fold when the crop was irrigated twice a day compared to the single drip watering regimes. The maximum grain yield (13.12 t/ha) and biomass (24.91 t/ha) were recorded in sorghum irrigated twice a day in the dry and dry-wet season, respectively. While the highest WUE (4.53) was registered from the sorghum irrigated twice a day in the dry-wet season, the lowest WUE (1.97) was registered in sorghum irrigated late in the evening in the dry season. The findings suggest that, although irrigating early in the morning or late in the evening in dry-wet season results in nine times more grain yield than under rainfed condition (0.9 t/ha), it is recommended to irrigate sorghum twice a day, not only in the dry season but also during the rainfall season by supplementing hydric deficit for a higher growth performance, grain yield, and efficient water productivity.