TITLE:
Evaluation of Crop Yield Response to Water Use Efficiency in the Chauru Irrigation Scheme, Tanzania
AUTHORS:
Bigilimana Thomas, Edmund Mutayoba, Eunice Makungu
KEYWORDS:
Water Use Efficiency, Crop Yield, AquaCrop, Deficit Irrigation, Full Irrigation, Rice Production, Chauru Scheme
JOURNAL NAME:
Journal of Geoscience and Environment Protection,
Vol.13 No.9,
September
16,
2025
ABSTRACT: It was reported by this paper that diverse irrigation management strategies, crop yield, and the water use efficiency (WUE) impact of those strategies were outlined in the Chauru Irrigation Scheme, Pwani Region. Additionally, with water scarcity on the rise, the allocation of water in agriculture must be done in a manner that is compatible with the sustainability of food production. This research primarily aims to measure the relation between the amount of irrigation water used, the actual evapotranspiration, and crop yield; at the same time, it looks for the water use efficiency (WUE) that comes out from the different scenarios. Concrete activities were undertaken in the field to perform trials on rice (paddy) in 2024 over the representative blocks of the scheme at full irrigation (100% ETc) and at deficit irrigation (85% ETc and 70% ETc), with both rainfed and farmer practice treatments for certain growth stages besides farmer practices. The field research includes the collection of information on yield, irrigation water used, precipitation, soil water content, and meteorological parameters that are further processed by employing crop simulation models like Aqua Crop. According to the results, the 85% ETc treatment gave a crop yield equivalent to full irrigation (6.2 t/ha) but with 15% less water, resulting in a higher crop WUE (1.18 kg/m3) compared with full irrigation (1.03 kg/m3). Treatment 70% ETc achieved the highest crop water use efficiency (1.31 kg/m3), although it showed a slight decrease in yield (5.5 t/ha). Both rainfed and farmer practice treatments had the lowest yields and crop WUE values; the vulnerability of the system to unmanaged water supply and rainfall variability is evident. In this case, the results of the research at hand confirm that moderate deficit irrigation could keep the yields high and increase water productivity a lot at the same time. Under controlled experiments, the Chauru Irrigation Scheme exhibited technical efficiency in water delivery and yield support capacity. However, the gap between the best treatments and farmer practices seems to reveal the possibility of improving on-farm water management. Incorrect timing, uneven distribution of water, and the absence of an irrigation schedule that is properly followed are the main reasons for sub-optimal WUE under actual farmer plot conditions.