The Effects of Saline Water Irrigation on Soil Salinity and Physiology of Greenhouse Tomato

Abstract

【Objective】 Saline groundwater is a complementary water resource for irrigation in Xinjiang, but its application needs calculated management. The aim of this paper is to study the impact of saline water irrigation on soil salt content and physiology of greenhouse tomatoes. 【Method】 The experiment was conducted in southern Xinjiang, and the crop was drip-irrigated using water with salinity at 2 g/L (T1), 4 g/L (T2), 6 g/L(T3) and 8 g/L (T4), respectively. Fresh water irrigation was taken as the control (CK). The irrigation amount and irrigation frequency in all the treatments were the same. In each treatment, we measured soil salt content and physiological indexes of the crop. 【Result】 Vertically, soil salt content decreased along the depth, regardless of the treatments; horizontally, soil salt accumulated in soil 20~40 cm away from the emitter. At the end of the growth period, salt accumulated predominantly in 20~60 cm soil layer. Salt accumulation area increased with the increase in irrigation water salinity. Irrigating with water salinity in 2~4 g/L promoted tomato growth and thickened its stems, despite of its insignificant effects on dry biomass. Increasing water salinity to 6~8 g/L inhibited crop growth. When water salinity was 2 g/L, the total chlorophyll and carotenoid contents in the crop maximized. When water salinity was greater than 4 g/L, a large amount of active oxygen accumulated in organs exceeded the scavenging capacity of the protective enzymes. Irrigation when water salinity was in 2~4 g/L improved both fruit yield and quality. 【Conclusion】 Considering salt distribution and plant growth, groundwater with salinity in the range of 2 to 4 g/L can be used as a complementary water resource to irrigate greenhouse tomatoes in southern Xinjiang.

Keywords

• tomato
• salt water
• plant growth
• leaf physiology
• yield
• quality