Effects of irrigation threshold on the water consumption, yield, and quality of Chinese cabbage in Bashang Area

The vegetable production in Bashang Area of Hebei is facing the problem of low water use efficiency caused by extensive irrigation management. It is urgent to build a high-yield, high-quality, and water-saving collaborative precision irrigation mode. In this study, the Chinese cabbage in this area was taken as the research object, and different irrigation thresholds were set at seedling stage, rosette stage, and heading stage. Specifically, the total irrigation amounts of W1 80%−95% field capacity (FC) at seedling stage, 80%−95% FC at rosette stage, and 80%−90% FC at heading stage, W2 (80%−90% FC at seedling stage, 70%−90% FC at rosette stage, and 70%−85% FC at heading stage), and W3 (80%−100% FC at seedling stage, 60%−100% FC at rosette stage, and 60%−100% FC at heading stage) were 170.5, 135.1, and 210.4 mm, respectively. The effects of soil water threshold regulation of drip irrigation under film on crop water consumption, yield, and quality were explored. The results indicated that compared with W3 (the highest irrigation amount), W2 showed the decreases of 35.7% and 18.1% in the irrigation and evapotranspiration, respectively, with no significant reduction in the yields of untrimmed and trimmed vegetables. Compared with W3, the irrigation and evapotranspiration of W1 decreased by 39.8 and 25.3 mm, respectively, resulting in a 10.0% decrease in trimmed vegetable yield. Comparison of the three irrigation schemes showed that W2 exhibited increases of 25.2% and 20.1% in the water use efficiency and 40.8% and 53.0% in the irrigation water use efficiency compared with W1 and W3, respectively. Moreover, W2 had the best vegetable quality (nitrate content: 1422.7 mg/kg; vitamin C: 250.5 mg/kg). In general, W2 can meet the soil water demand of Chinese cabbage at different growth stages, which is consistent with the water demand law of crops. Selecting the appropriate soil water threshold and irrigation amount for precise water control enables the reduction in water consumption under the premise of ensuring the yields and quality of untrimmed and trimmed vegetables and the synergistic improvement of water use efficiency and irrigation water use efficiency. The results of this study provide an important theoretical basis and technical support for the construction of an efficient water-saving production system of Chinese cabbage in Bashang Plateau in cold and arid regions.