Effect of aerated drip irrigation and nitrogen doses on N2O emissions, microbial activity, and yield of tomato and muskmelon under greenhouse conditions

Soil nitrous oxide (N2O) emissions are strongly affected by field practices, including irrigation and fertilization. This study investigated whether aerated drip irrigation (ADI) can enhance the soil environment, mitigate N2O emissions, and improve crop yields relative to conventional drip irrigation (DI). Tomato and muskmelon crops were grown in a solar greenhouse under different irrigation methods (DI and ADI) and nitrogen fertilizer rates (tomato: 0, 150, 200, and 250 kg N ha–1; muskmelon: 0, 150, and 225 kg N ha–1). The results showed that ADI increased soil temperature by 1.3–7.0 %, oxygen concentration by 1.9–3.2 %, and soil NH4+ and NO3– concentrations in the upper soil layers (0–60 cm) by 3.7–27.1 % and 3.6–51.5 % and decreased soil NH4+ and NO3– concentrations from 60 to 100 cm depth by 5.0–17.6 % and 1.9–18.9 %, relative to DI. However, ADI decreased soil moisture by 2.3–3.6 %. ADI also significantly increased soil microbial activity by 0.5–28.6 %. In addition, ADI and 150 kg N ha–1 significantly reduced yield-scaled N2O emissions (YSNES) and emission factors (EF), increasing tomato and muskmelon yields. The results of this study suggest that ADI combined with appropriate N application rates can improve soil productivity and mitigate N2O emissions.