Transplanting tef boosts yield, nutrient, and water use efficiencies under optimal nitrogen uses in semiarid areas

Tef (Eragrostis tef) in Ethiopia has low nutrient use efficiency, with transplanting potentially improving nitrogen use, water efficiency, and yield compared to conventional broadcasting. This study evaluates the combined effects of different planting methods and nitrogen fertilizer levels on the yield, nutrient, and water use efficiency of irrigated tef crops. Four planting methods (broadcasting, row planting, pelleting, and transplanting) were tested alongside five nitrogen levels (0, 46, 92, 138, and 184 kg/ha) over two consecutive years. Analysis of variance revealed significant effects of planting methods, nitrogen levels, and their interactions on key variables, including lodging index, biomass yield, grain yield, nutrient use efficiency, water use efficiency, and economic water productivity (p < 0.05). Transplanted tef demonstrated remarkable improvements: a 650% reduction in lodging index, a 94% increase in shoot biomass, an 80% increase in grain yield, and a 78% improvement in agronomic use efficiency compared to broadcasting. Additionally, transplanting maintained low lodging levels even with higher nitrogen applications, unlike other methods where lodging increased with increased nitrogen levels, and reduced yields. Transplanted tef with 92 kg/ha of nitrogen showed the highest nitrogen use efficiency and economic returns, offering the greatest yield benefits per unit of nitrogen applied. These results suggest that transplanting, combined with optimized nitrogen levels, significantly enhances productivity, water use efficiency, and economic returns while reducing environmental impacts. This approach offers practical solutions for improving tef farming practices, particularly in regions with similar agroecological conditions.