Response of Tomato (Solanum lycopersicum L.) to Irrigation and N-fertilizer Levels in Semi-arid Parts of Tigray, Ethiopia

Increasing crop productivity can be achieved through the proper use of water and fertilizer. In Tselemty district, Tigay, Ethiopia, a field experiment was conducted during the irrigation seasons of 2019 and 2020 to identify the optimal nitrogen rate and irrigation depth for maximizing tomato yield. The study involved factorial combinations of three irrigation depths (75% ETc, 100% ETc, and 125% ETc) and three nitrogen rates (75%, 100%, and 125% of the recommended amount). These treatments were laid out in a randomized complete block design (RCBD) with three replications. Data were collected on various growth and yield-related factors for tomatoes, including plant height, number of fruits per plant, fruit length, fruit diameter, marketable yield, and unmarketable yield. The collected data were analyzed using R software to determine statistical significance. The results showed that changing the rates of nitrogen fertilizer and the amounts of irrigation had little effect on the growth and yield of tomatoes. Likewise, the marketable yield remained largely unaffected by the different treatments of nitrogen and irrigation. Therefore, it is advisable for tomato farmers in the region to use a combination of 100% of the evapotranspiration crop (ETc) and 100% of the recommended nitrogen fertilizer when resources allow. When water and fertilizer are limited, using 75% of ETc along with 75% of the recommended nitrogen fertilizer can improve water use efficiency while keeping yield levels stable in dryland irrigated agriculture.