Effects of water and nitrogen coupling on economic yield and water and nitrogen use efficiency of cabbage

In order to explore the effects of different water and nitrogen coupling on economic yield, economic benefit, nitrogen use efficiency and water productivity of cabbage, and optimize the water and nitrogen management measures in the field of cabbage. This study takes Zhonggan 15 as the research object, and sets two irrigation modes（conventional irrigation（W1）and water-saving irrigation（W2, 70% of conventional irrigation)). Four nitrogen application levels（0 kg·hm⁻²（N0）, 119.94 kg·hm⁻²（N1）, 239.88 kg·hm⁻²（N2）, 359.82 kg·hm⁻²（N3））were used to analyze the effects of different water-nitrogen coupling on economic yield and economic benefit, nitrogen use efficiency and water productivity of cabbage. The results showed as follows: ① Nitrogen application rate and irrigation mode had significant effects on economic yield, nitrogen use efficiency and water productivity of cabbage（p＜0.05）. The economic yield and water productivity increased first and then decreased with the increase of nitrogen application rate. Under the same nitrogen application rate, the nitrogen use efficiency was higher under water-saving irrigation mode. ②The economic yield, economic benefit and water productivity of cabbage treated with W2N2 were the highest, which were 16.11 t·hm⁻², 16544.73 yuan·hm⁻² and 4.88%, respectively, and significantly increased by 14.34%, 11.50% and 64.31% compared with W1N1 treatment, respectively. Therefore, the optimal water-nitrogen coupling mode for cabbage formation is as follows: water-saving irrigation mode, irrigation amount is 330 t·hm⁻², nitrogen application amount is 239.88 kg·hm⁻². Appropriate and moderate water-nitrogen coupling mode has the potential of increasing production, high efficiency and saving water.