The Combined Effect of Irrigation and Fertilization on Soil Water, Nutrient Transport, Yield and Water Use Efficiency of Greenhouse Tomato

Abstract

【Objective】 Greenhouse vegetable production relies on irrigation and fertilization. Improving their use efficiency can reduce the operational costs and environmental impact. The objective of this paper is to find their optimal combination for greenhouse tomato production. 【Method】 The experiment consisted of three irrigation treatments: conventional drip irrigation at 4 800 m3/hm2 (W1), reducing W1 by 25% (W2), and 50% (W2); and three fertilizations: high fertilization at 7 200 kg/hm2 (F1), and reducing F1 by 30% (F2), and 60% (F3). In each treatment, we measured soil water distribution, and yield and water use efficiency of the tomato. 【Result】 Fertilization and irrigation were strongly interacted in their impact on tomato yield, soil water and nutrients. Compared to W1+F1, W2+F2 and W3+F2 reduced the fruit yield by 16.26% and 6.54%, and increased water use efficiency by 11.62% and 66.56%, respectively. Soil water content in the 0~20 cm soil layer exhibited oscillation in the range of 13.33%~24.53%, but overall showed a declined trend as the crop grew. With the decrease in irrigation and fertilization, the gradient of soil water content at the depth of 60 cm became steeper. The average soil water content under W2+F2 and W3+F2 was 16.53% and 16.84%, respectively. Soil organic matter and bioavailable nutrients were more abundant in the later growth stage than in the middle growth stage. Soil organic matter and bioavailable phosphorus, potassium in root zone were comparable in all treatments, both decreasing with the decrease in fertilization when the irrigation amount was the same. When the fertilization was the same, a moderate reduction in irrigation amount could reduce the downward movement of alkali-hydrolyzed nitrogen, bioavailable phosphorus and potassium, thereby increasing nutrients in the root zone. 【Conclusion】 Among all the treatments we compared, the optimal irrigation and fertilization to give the best yield and water use efficiency was drip-irrigation with 2 400~3 600 m3/hm2 of water, and fertilization with 3 600 kg/hm2 of liquid organic fertilizer and 1 440 kg/hm2 of water-soluble fertilizer.

Keywords

• irrigation and fertilization coupling
• facility fruit tomato
• yield
• soil water content
• soil nutrients