Effects of Different Irrigation and Fertilization Practices on Nitrogen Balance and Yield on Greenhouse Eggplant (Solanum melongen L.) in Mollisols

Abstract

ABSTRACT Balancing the nitrogen (N) budgets of agricultural production is crucial to maintaining yield and reducing the environmental pollution, especially in vegetable systems. Here, a systematic study was conducted on eggplant (Solanum melongena L.) yield, N uptake, N leaching and N balance in response to regular fertilization and irrigation (WF), reducing 20% of chemical fertilizers (W + 80%F), reducing 20% of irrigation amount (80%W+F), and biochar addition (WF+B) in a greenhouse eggplant system in Northeastern China. The results showed that compared with WF, 80%W+F treatment decreased eggplant yield, N uptake and N leaching by 11%, 23% and 14%, respectively. However, it increased N surplus by 30%. W + 80%F not only decreased N surplus by 4% and improved N balance, but also maintained eggplant yield and N uptake. WF+B significantly increased eggplant yield and N uptake, however, it sharply increased N surplus by 141% and caused N imbalance. Therefore, these results demonstrated that reducing chemical fertilizers by 20% would be the most suitable management practice for maintaining eggplant yield and reducing N surplus in greenhouse vegetable systems.