Response of deficit irrigation on soil CO2 and N2O emissions in greenhouse tomato fields

Abstract

<b>Abstract.</b> Deficit irrigation is an important factor regulating gas emissions in greenhouse vegetable systems. However, information regarding the response of soil CO₂ and N₂O emissions and yield to deficit irrigation is limited. In our study, a three-year field experiment was implemented in a solar greenhouse to investigate the effect of deficit irrigation on soil CO₂ and N₂O emissions and tomato yield. Three irrigation treatments were designed: full irrigation (FI), 20% deficit irrigation (DI20, 80%FI), and 40% deficit irrigation (DI40, 60%FI). Compared with the FI treatment, deficit irrigation decreased soil CO₂ and N₂O emissions by 0.6%−14.3% and 0.9%−44.2%, respectively. The integrative global warming potential of CO₂ and N₂O under the FI treatment was increased by 10.3% and 0.4% compared with DI40 and DI20 treatments, respectively. Soil temperature, urease, and catalase activity were major factors influencing CO₂ flux, where N₂O flux was soil water and NO₃^− content. Tomato yield for the FI treatment (34.36 t ha^−1) was significantly increased, by 24.3% and 21.0% compared with the DI40 and DI20 treatments, respectively. Considering the yield and greenhouse effect, FI was recommended as the best irrigation mode. This study provides a reference for formulating greenhouse tomato irrigation management that obtains gas reduction and high yields.