Grain Yield and Economic Returns of Sesame (Sesamum indicum L.) Induced by In-situ Moisture Conservation and Sulfur Fertilization on Vertisol of Western Tigray, Ethiopia

A field experiment was conducted in 2015 and 2016 to evaluate the effects of in-situ moisture conservation using tied-ridging and conventional flatbed tillage practices combined with five sulfur fertilizer rates (0, 10, 20, 30 and 40 kg ha-1). The experiment was lied out in a split plot design with three replications under rain-fed conditions. A newly released improved variety of sesame“Setit 1” was used as a test crop. Most of the agronomic data were collected at harvest. The collected data were analyzed using GenStat16 EdSP. The marginal rate of return was also estimated from the total revenue and total variable cost. Results show that there was a significant (P < 0.05) difference due to the combined effects of tied ridges and sulfur fertilizer rates on grain yield, days to 90% maturity, number of branches per plant, plant height, and number of capsules per plant except the days to 50% flowering in 2015. But, in 2016 there was no significant (P > 0.05) difference by the combined effect. The highest grain yield of 889.3 kg ha-1 as well as the corresponding highest net revenue of 14,239.4 Ethiopian Birr was recorded at 40 kg S ha-1 under tied ridges, but this was statistically not significant (P > 0.05) with the grain yield of 857.6 kg ha-1obtained using 30 kg S ha-1combined with tied ridges in 2015. However, in 2016 the significant difference resulted were due sulfur fertilizer but not due to the combined effect of tillage practices and sulfur fertilizer, hence calculating partial budget analysis is not necessary for statistically non-significant results. Therefore, sulfur fertilizer rate at 30 kg ha-1combined with tied ridges is most economically feasible technologies for the farmers to increase sesame productivity at Kafta Humera district.