Aerated irrigation increases tomato production by improving soil nitrogen availability

Soil nitrogen (N) is the main limiting nutrient for plant growth, which is sensitive to variations in the soil oxygen environment. To provide insights into plant N accumulation and yield under aerated and drip irrigation, a greenhouse tomato experiment was conducted with six treatments, including three fertilization types: inorganic fertilizer (NPK); organic fertilizer (OM); chemical (75% of applied N)+organic fertilizer (25%) (NPK+OM) under drip irrigation (DI) and aerated irrigation (AI) methods. Under AI, total soil carbon mineralization (Cmin) was significantly higher (by 5.7–7.0%) than under DI irrigation. Cmin in the fertilizer treatments followed the order NPK+OM>OM>NPK under both AI and DI. Potentially mineralizable C (C0) and N (N0) was greater under AI than under DI. Gross N mineralization, gross nitrification, and NH4+ immobilization rates were significantly higher under the AINPK treatment than the DINPK treatment by 2.58–3.27-, 1.25–1.44-, and 1–1.26-fold, respectively. These findings demonstrated that AI and the addition of organic fertilizer accelerated the turnover of soil organic matter and N transformation processes, thereby enhancing N availability. Moreover, the combination of AI and organic fertilizer application was found to promote root growth (8.4–10.6%), increase the duration of the period of rapid N accumulation (ΔT), and increase the maximum N accumulation rate (Vmax), subsequently encouraging aboveground dry matter accumulation. Consequently, the AI treatment yield was significantly greater (by 6.3–12.4%) than under the DI treatment. Further, N partial factor productivity (NPFP) and N harvest index (NHI) were greater under AI than under DI, by 6.3 to 12.4%, and 4.6 to 8.1%, respectively. The rankings of yield and NPFP remained consistent, with NPK+OM>OM>NPK under both AI and DI treatments. These results highlighted the positive impacts of AI and organic fertilizer application on soil N availability, N uptake, and overall crop yield in tomato. The optimal management measure was identified as the AINPK+OM treatment, which led to more efficient N management, better crop growth, higher yield, and more sustainable agricultural practices.