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 (YSNE_S) 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.