Growth and yield components of tomato as influenced by nitrogen and phosphorus fertilizer applications in different growing seasons

Tomato is an important cash crop in Central Rift Valley of Ethiopia. However, the yield is constrained by poor soil fertility management and lack of appropriate/adequate fertilizers rates recommendation. Experiments were conducted at Melkassa on station with the objectives of evaluating effect of N and P fertilizer applications on growth and yield, and determining optimal requirements for tomato. The experiments were conducted under both cool season furrow irrigated and rain-fed conditions with variable fertility status of the fields. The treatments consisted of four rates of nitrogen (0, 50, 100 and 150 kg N ha-1) and four rates of P (0, 46, 92 and 138 kg ha-1). The experiments were laid out in a CRBD in a factorial arrangement and replicated three times using Melkashola variety. Data on growth and canopy characteristics such as plant height and stem diameter, main lateral branch length, canopy width and depth were measured from selected plants. Some of the growth and yield components such plant height, canopy diameter, canopy width, stem diameter, lateral branch length, total dry mass above the ground per plot, shoot fresh and dry weight, marketable and unmarketable fruit yield and total yield at harvest were measured were assessed. Maximum fruit yield was estimated from regression lines of applying 105 kg N ha-1 and 85 kg P ha-1 under furrow irrigated experiment (continuously cultivated field). However, the highest fruit yield was from application of 40 kg N ha-1 and 10 kg ha-1 for the rainfed experiment (relatively fertile field). Thus, results of both experiments were averaged to propose on farm verification of N and P requirement of tomato, N 73 kg ha-1 and P 48 kg ha-1 around Melkassa and similar soil types.Keywords: furrow irrigated, rain-fed, season, tomato, inorganic N and P fertilize