Assessment of Water Productivity and Economic Viability of Greenhouse-Grown Tomatoes under Soilless and Soil-Based Cultivations

Water scarcity has necessitated the adoption of water-saving techniques in both protected and non-protected farming. This study aimed to evaluate the performance of a water-saving soilless cultivation technique and compare it to conventional soil-based cultivation in protected farming. The soilless technique utilized local gravel and a mixture of peat moss, humin-substrate, and perlite in a 4:3:1.5 ratio. During the tomato growth cycle, three irrigation regimes were imposed using drip irrigation: 8 Lh-1 design discharge (D1) emitters, 6 Lh-1 design discharge (D0.75) emitters, and 4 Lh-1 design discharge (D0.5) emitters for both cultivation methods. Vegetative growth, fruit yield, and water consumption were measured and water productivity was determined. Additionally, an economic assessment was conducted by estimating and comparing economic coefficients for both cultivation methods. Estimated coefficients included revenues, net profit, benefit-cost ratio, breakeven levels of production and prices, revenues over variable cost, and revenues on investment. The tomato fruit yield under soil-based cultivation surpassed the yield under soilless cultivation. Water productivity under soilless cultivation was nearly double (24.3 kg m-3) that of soil-based cultivation (15.5 kg m-3). Soilless cultivation saved 50% of the irrigation water applied by the conventional soil-based method, conserving energy and protecting the soil from deterioration. Revenues and net profits, driven by higher yield and lower variable costs, favored soil-based cultivation. The economic assessment demonstrated that both cultivation methods were economically viable. However, the soil-based cultivation method was more profitable due to its higher fruit yield. Overall, the results of this study suggest that the soilless cultivation technique is a feasible option for water-saving cultivation. However, the soil-based cultivation method remains more profitable due to its superior fruit yield. The soilless cultivation technique offers significant water savings but needs further improvements to achieve comparable economic returns to traditional farming.