Effect of Soil Physicochemical and Irrigation Scheduling on Yield and water productivity of Irrigated Maize (Zea Mays) at Haiba Irrigation Scheme, Tigray, North Ethiopia

Abstract

In Tigray, traditional soil and water management practices have significantly undermined government efforts to achieve food security, particularly in areas with limited soil fertility and water resources. In such contexts, the application of soil fertility amendments and the adoption of appropriate irrigation techniques become critical priorities. This study aimed tevaluate the effects of soil physicochemical properties and irrigation scheduling on the yield and water productivity of irrigated maize (Zea mays) at the Haiba Irrigation Scheme, thereby contributing to sustainable agricultural and soil and water management practices in the highlands of semi-arid Ethiopia. Soil samples were collected and analyzed for key physicochemical properties, including texture, pH, electrical conductivity, organic matter content, and essential nutrient levels. Concurrently, field trials were conducted to assess different irrigation schedules, notably conventional and regulated deficit irrigation strategies, during the critical growth stages of maize. The crop water requirements were estimated using CROPWAT 8 software, allowing for a comparative analysis of scientific (CropWat) and traditional farmers' irrigation scheduling methods based on yield, crop water productivity (CWP), irrigation water productivity (IWP), and economic water productivity (EWP) during the 2019 cropping season. The experiment employed a randomized complete block design (RCBD) across three sites with three replications, incorporating two treatments. Statistical analyses were performed using Minitab and SPSS software. Results indicated that yield and yield components, along with CWP and IWP metrics, were statistically higher in the CropWat scheduling treatments compared to traditional methods (p < 0.05). The total average water applied was 790 mm for the CropWat method and 886 mm for the traditional method, revealing that farmers applied 12% more water than recommended, leading to over-irrigation. The CropWat scheduling method resulted in a water savings of 96.4 mm, sufficient to irrigate an additional 0.2 hectares. Maize yields under CropWat scheduling reached 5.25 t/ha, significantly higher than the 2.32 t/ha achieved with traditional scheduling. The improved crop water productivity (CWP), irrigation water productivity (IWP), and economic water productivity (EWP) reinforce the recommendation for adopting CropWat-based irrigation scheduling at the Haiba Irrigation Scheme. For successful adoption, it is essential to improve farmers' irrigation water management skills through targeted training and technical support from experts.