Effects of irrigation strategies and N sidedressing on the yield and N utilization of greenhouse tomato

Greenhouse tomato experiment was conducted in Shouguang, Shandong province in order to investigate the effects of irrigation strategies and N sidedressing on fruit yield and N utilization in greenhouse tomato. Compared with conventional fertilization and irrigation practices, real-time control of rootzone N management and related target values were used to optimize N sidedressing during the growing season. Two kinds of irrigation strategies, including irrigation up to field capacity (FC) and fixed amount based on soil texture (FA), were employed with bubbler irrigation system. The results showed that under conventional irrigation practice, there were no significant differences on tomato fruit yield under optimized N management, which accounted for 48% N input of conventional N fertilization. Except for transplanting stage, two irrigation strategies (FC and FA regimes) could reduce 46% and 30% irrigation compared to conventional practices. With the same N target value, these irrigation strategies could save 14% and 10% fertilizer N in the treatment with optimized N management. The FC and FA strategies could significantly reduce apparent N loss in the soil-vegetable system; consequently, decrease the negative environmental impact due to excessive N input.