Enhancing Moringa stenopetala leaf yield and nutritional composition under supplemental irrigation in arid regions of Eastern Ethiopia

Moringa stenopetala is a nutrient-dense tree crucial for combating micronutrient deficiencies in arid regions. This study investigated the effects of supplemental irrigation on leaf biomass yield and nutritional composition of M. stenopetala in the Kobo district, eastern Ethiopia. A randomized complete block design was employed with irrigation intervals of 10, 15, and 30 days, plus a rain-fed control. Leaf harvests occurred at 21 and 26 months after planting. Irrigation at 10- and 15-day intervals significantly increased dry leaf biomass yield compared to the control, with the 10-day interval yielding the highest (0.77 and 0.56 t/ha in first and second harvests, respectively). These intervals also improved growth parameters like plant height and branch number. Proximate and mineral analysis revealed that the leaves were rich in fat (11.7-13.8%), ash (5.9-6%), and fiber (9.7-10.6%), and contained substantial amounts of iron and zinc. Notably, the nutritional composition remained consistent across irrigation treatments and aligned with WHO standards, despite variations in biomass. Anti-nutritional factors (phytate and tannin) were present but did not vary significantly with irrigation. We conclude that while supplemental irrigation significantly enhances leaf biomass production, it does not alter the fundamental nutrient profile of M. stenopetala leaves. For optimal leaf production, irrigation every 10 days is recommended where water is abundant; otherwise, a 15-day interval is a viable, water-efficient alternative.