Effect of Drip Irrigation and Fertigation on Soil Water Dynamics and Productivity of Greenhouse Tomatoes

The proficient supply of water and nutrients is a key factor for successful vegetable production under greenhouses. This field experiment was conducted during 2018-2019 under a completely randomized design to evaluate the effects of drip irrigation and nutrient schedule on soil water dynamics and the productivity of greenhouse tomato. The experiment consisted of two irrigation schedules, i.e., I-1 (irrigation applied from week 1 to 2 on the basis of 100% pan evaporation (E-pan), week 3 to 8 on the basis of 40% of E-pan, week 9 to 14 on the basis of 60% of E-pan, week 15 to 20 on the basis of 80% of E-pan, week 21 to 24 on the basis of 100% of E-pan) and I-2 (irrigation applied on the basis of 100% of E-pan throughout the crop period) with a five-nutrient schedule, viz., F-1 (100% NPK applied through the conventional method), F-2 (100% N applied through fertigation + PK through the conventional method), F-3 (100% NK applied through fertigation + P through the conventional method), F-4 (100% NPK applied through fertigation) and F-5 (50% NPK applied through the conventional method + 150% NPK applied through fertigation). The soil moisture content (SMC) and its depletion were measured during growing season. The tomato yield was significantly higher under I-2. However, water use efficiency (WUE) was significantly higher under I-1 treatment. Among the nutrient schedules, the yield and WUE were significantly higher in F-5 treatment. The net returns were highest under F-5 and lowest under F-1. The Benefit:Cost ratio was highest in F-4 and lowest under F-1. The irrigation level I-2 (irrigation applied on the basis of 100% of E-pan throughout the crop period) with fertigation treatment F-4 (100% NPK applied through fertigation) was the best strategy for obtaining the maximum productivity of tomato under the greenhouse. It can be concluded that the drip-based fertigation enhances the crop yield and net returns and therefore may be promoted to increase the income of the farmers.