Effects of water stress on processing tomatoes yield, quality and water use efficiency with plastic mulched drip irrigation in sandy soil of the Hetao Irrigation District

Processing tomatoes are major cash crops in the Hetao Irrigation District, Inner Mongolia, China. Conventional irrigation practices have resulted in ecological and environmental problems due to the specific climate and groundwater conditions. Field experiments were conducted to investigate the effects of water stress on processing tomatoes yield, quality, and water use efficiency with plastic mulched drip irrigation in sandy soil of the Hetao Irrigation District. Tomatoes were irrigated at 40%, 60%, 70%, 80% and 100% of crop evapotranspiration (ETc). Results showed that soil water content and salt concentration mainly varied in the upper 60 cm soil layer. Dry aboveground biomass and yield increased with increased ETc to 80 or 100%. The highest yield was obtained with 80% ETc treatment both years (70 and 81 t/ha). Increasing water stress led to the increase of soluble solids content and Vitamin C. Actual evapotranspiration (ETa) ranged from 188 to 323 mm in the two seasons, and increased quadratically when the irrigation depth increased to 80% ETc. The highest water use efficiency (WUE) was found at 60% ETc treatment in 2013 and 80% ETc treatment in 2014. Comprehensive analysis of yield, WUE and ETa, irrigated at 80% ETc was recommended as the optimal irrigation strategy in the sandy soil of the Hetao Irrigation District.