Optimizing N fertilizer use for sesame under rain fed and irrigation conditions in Northern Ethiopia

Inappropriate use of fertilizers is one of the major production constraints in sesame. Studies on N fertilizer optimization on sesame were conducted at Humera Agricultural Research Center (HuARC) under rain fed and irrigation conditions. Thirteen (13) N doses were evaluated in a Randomized Complete Block Design (RCBD) during 2016–2018 for rainfed conditions and 2017 to 2019 for irrigation conditions. The study was conducted with objective to optimize N fertilizer use for sesame. In the rainfed condition, the results demonstrated a prolonged duration to reach 50% flowering with higher nitrogen (N) application rates. The application of 52.5–110 ​kg ​N ha⁻¹ resulted in significantly higher seed yield, while lower (18 ​kg ​N ha⁻¹) and higher (156 ​kg ​N ha⁻¹) doses of N led to reduced seed yield. Under irrigation conditions, superior seed weights and maximum seed yield were observed at 64 and 75 ​kg ​N ha-1, whereas lower N doses resulted in diminished seed yield. The agronomic efficiency of N fertilizer (N-AE) was found to be highest at the rate of 64 ​kg ​N ha⁻¹ under both growing conditions. The partial budget analysis revealed that applying 64 ​kg ​N ha⁻¹ for rainfed cultivation and between 64 and 75 ​kg ​N ha⁻¹ for irrigated sesame production yielded greater net profit, MRR, and residual ranking. Therefore, it is recommended to apply a rate of 64 ​kg ​N ha⁻¹ for rainfed sesame cultivation and between 64 up to 75 ​kg ​N ha⁻¹ for the irrigated sesame inorder to increase the productivity of this crop.