Spatiotemporal Analysis of Land and Water Productivity Using WaPOR Data: A Case of Wonji Shoa Sugarcane Plantation, Ethiopia

Abstract

As competition for limited land and water resources grows, along with the need to feed a constantly increasing population, innovative methods are required to monitor the performance of irrigation systems and enhance land and water productivity. The Ethiopian government faces the challenge of boosting sugarcane yields in Wonji Shoa while simultaneously reducing water usage. Hence, this research analyzed the spatiotemporal distribution of land productivity, biomass water productivity, and irrigation performance indicators in Wonji Shoa. WaPORWP python library is used for assessing spatiotemporal land and water productivity, as well as other irrigation performance indicators using WaPOR data with 30m resolution from 2009-2022. The analysis covered six indicators: water consumption, uniformity, adequacy, beneficial fraction, land and water productivity, and productivity gaps differentiated by irrigation methods. The WaPOR data were first validated agronomically by examining the biomass response to water, and then the data were used to systematically analyze seasonal indicators for the period 2009-2022 on ???11,000 ha. The yield estimates based on WaPOR were found to be comparable to those measured on estates measured. Consequently, the average difference between WaPOR yield and observed yield was 24.68%, with a standard deviation of 19.52%. The analysis of ETact temporal variation revealed that water consumption increased during cropping seasons, indicating that the goals of the ABWAP for reducing water use have not been met. The highest water consumption rate was found in furrow-irrigated areas, whereas center-pivot irrigated areas had the lowest consumption and demonstrated the best performance in achieving irrigation uniformity. Furrow and sprinkler irrigation methods have a higher beneficial fraction than center pivot methods, and furrow irrigation has the highest adequacy levels compared to other methods. Although there were no noticeable changes in land productivity over time, differences in irrigation methods were observed among the fields. Furrow irrigation achieved the highest biomass production (120.4 tons/ha/year), while center pivot irrigation produced the lowest output (110.5 tons/ha/year). The temporal variation of water productivity decreased over time and the performance in irrigated areas reveals an average WPb of 8.33 ??? , with sprinkler-irrigated areas ranking the highest at 8.53 ??? . Some areas exhibit both higher and lower WPb values, indicating the potential for improvement in underperforming portions. A 13-year average production gap of 39.0 tons/ha/year was observed in certain areas using furrow and sprinkler irrigation methods, while other areas experienced a gap ranging from 76.2 to 113.2 tons/ha/year. The water productivity gap ranges from 0.014 ???????????? ??????3 ??? /???????????????????????? in furrow irrigated areas to 1.26-3.8 ???????????? ??????3 ??? /???????????????????????? in areas using sprinkler and center pivot systems.Closing the biomass gap at Wonji Shoa could increase biomass production from 119.9 ton/ha/year to 162.4 tons/ha/year, resulting in an additional 466,947.5 tons/year and closing the WPb raising the WPb from 8.3 3 ??? to 8.5 3 ??? . Zonal analysis from 2009-2022 reveals significant variations in crop yield, water productivity, and yield gap across various zones. Zones 4, 7, and 8 showed high efficiency in water use and better agricultural performance, whereas zones 13 and 18 struggled. This research contributes to a better understanding of RS-based evaluations, providing an economical solution for conducting extensive analyses to pinpoint areas with varying productivity levels and compare irrigation practices across different schemes and cropping seasons. The findings can be useful in identifying opportunities for enhancement by determining the conditions necessary for achieving optimal land and water productivity.