Five-year controlled-release/stable nitrogen fertilization reduces field nitrogen loss without increasing carbon dioxide emissions in a vegetable rotation system

Journal article, 2025

Controlled-release/stable nitrogen (N) fertilizers can improve vegetable yields and achieve lower greenhouse gas emissions, resulting in cost-effective and environmentally friendly vegetable production. However, there has been limited research on the controlled-release/stable N fertilization in long-term fixed-position vegetable rotation fields. In this study, a five-year field experiment was conducted to examine the effects of long-term controlled-release/stable N fertilization in reducing greenhouse gas emissions and increasing lettuce yield. Six distinct treatments were employed for N fertilization: the control without N fertilizer (CK), normal local farming practices with application of urea fertilizer at 400 kg N ha^-1 (T1), optimized application of urea at 320 kg N ha^-1 (T2), optimized application of urea at 320 kg N ha^-1 with supplementation of 1.0 kg ha^-1 3,4-dimethylpyrazole phosphate (DMPP) as N inhibitor (T3), application of polyurethane-coated urea at 320 kg N ha^-1 (T4), and application of polyurethane-coated urea at 320 kg N ha^-1 with supplementation of 1.0 kg ha^-1 DMPP (T5). The results showed that the T3, T4, and T5 treatments using controlled-release/stable N fertilization emitted about 12.2%–56.7% less average annual cumulative nitrous oxide (N2O) and 1.31%–10.0% less carbon dioxide (CO2) than the T2 treatment. Nitrous oxide and CO2 emissions from the T4 and T5 treatments were considerably lower than those from the T3 treatment. No significant seasonal or interannual variability was observed in N2O and CO2 emissions. The observed phenomena were attributed to the fluctuations in soil ammonium- and nitrate-N contents. The findings in this study revealed that long-term controlled-release/stable N fertilization resulted in reduced field N loss, benefitting vegetable yields without increasing CO2 emissions and highlighting the application potential of this technique for sustainable agricultural production.