Aerated Irrigation Enhances Nitrogen Use Efficiency and Soil Respiration in Greenhouse Tomato
摘要
High nitrogen input is commonly used in greenhouse tomato production to boost yields, but this practice leads to nitrogen waste and environmental issues. This study investigates how aerated irrigation can sustain plant nitrogen accumulation and yield with lower nitrogen input. In this study, a completely randomized experiment with two factors at three levels each was carried out with greenhouse tomato crops grown on a clay loam soil. The effects of aerated irrigation on soil respiration and the dynamic changes of plant nitrogen accumulation and growth characteristics of tomato plants under different nitrogen inputs were analyzed. Subsurface drip irrigation was conducted at the aeration rates of 5 mg·L− 1 (A1, conventional irrigation water), 15 mg·L− 1 (A2), and 30 mg·L− 1 (A3), with nitrogen application at 160 kg·ha− 1 (N1), 240 kg·ha− 1 (N2), and 320 kg·ha− 1 (N3). The results showed that aerated irrigation increased soil respiration rate, facilitated root growth and vitality, and was beneficial to nitrogen uptake. However, at the same aeration level, increasing the nitrogen application rate (from N2 to N3) did not lead to a further significant increase in plant nitrogen accumulation. By increasing the nitrogen accumulation rate, the plants shortened the rapid nitrogen accumulation period, increased the aboveground biomass accumulation, and thus increased the yield. The plant nitrogen uptake in aeration treatments was enhanced by 3.96–25.66% under various nitrogen levels, whereas soil nitrate-N concentration was decreased by 21.97–28.68% in the root zone. The multi-criteria compromise decision method VIKOR was used to select the optimal irrigation scheme. Under the treatment of aeration of 15 mg·L− 1 and nitrogen application of 160 kg·ha− 1, tomato quality, yield, and nitrogen use efficiency were comprehensively optimal. The research results can provide a theoretical basis and practical guidance for nitrogen fertilizer reduction production under greenhouse tomato aerated irrigation.