Effect of drip-line layout and irrigation amount on yield, irrigation water use efficiency, and quality of short-season tomato in Northwest China

Greenhouse tomato cropping with under-mulch drip irrigation is common in arid and semi-arid Northwest China. To investigate the influence of drip-line layout and irrigation amount on yield, fruit quality, irrigation water use efficiency, and comprehensive benefit of tomato production, the experiment was conducted during two cropping seasons of spring to summer in 2015 and winter in 2015 to spring in 2016. In these two cropping seasons, two drip-line layout types were conducted, including a one drip-line for each plant-row and a one drip-line for two plant-rows, with four levels of irrigation amount, i.e., 0.6, 0.8, 1.0, and 1.2 times of accumulated evaporation of a 20 cm standard pan. The results showed that one drip-line for two plant-rows outperformed one drip-line for each plant-row in achieving higher yield and irrigation water use efficiency with the same irrigation amount. In these two drip-line layouts, tomato yield increased at first and then decreased with the increase of irrigation amount; while irrigation water use efficiency decreased all the way with the increase of irrigation amount. A principal component analysis demonstrated that the combination of one drip-line for each plant-row and 1.0 times of pan evaporation obtained the highest comprehensive fruit nutritional quality among all combinations of drip-line layout and irrigation amount in spring-summer season; while the combination of one drip-line for two plant-rows and 0.8 times of pan evaporation had the highest comprehensive fruit quality in winter-spring season. To purse high comprehensive benefits, combinations of one drip-line for two plant-rows and 0.8 times of pan evaporation, and one drip-line for each plant-row and 0.6 times of pan evaporation should be recommended for spring-summer and winter spring cropping seasons, respectively. The findings of this study can provide irrigation guidance for greenhouse tomato growing in Northwest China.