Balancing high yields and low N.sub.2O emissions from greenhouse vegetable fields with large water and fertilizer input: a case study of multiple-year irrigation and nitrogen fertilizer regimes

• Published in: Plant and soil 2023-02, Vol.483 (1-2), p.131
• Main Authors: Ding, Wuhan, Zhang, Guilong, Xie, Haikuan, Chang, Naijie, Zhang, Jing, Zhang, Jianfeng, Li, Guichun
• Format: Article
• Language: English
• Subjects: Case studies; Crop yields; Emissions (Pollution); Environmental aspects; Irrigation; Nitrogen fertilizers; Nitrous oxide; Vegetables
• ISSN: 0032-079X
• DOI: 10.1007/s11104-022-05730-9

Background and aims Greenhouse vegetable production is commonly associated with substantial nitrous oxide (N.sub.2O) emissions, low nitrogen (N)and irrigation water use efficiency (NUE and IWUE) due to excess N input and frequent flooding irrigation, so it is crucial to develop irrigation and fertilization strategies to alleviate N.sub.2O emissions while ensuring vegetable productivity. Methods An experiment spanning three crop rotations of cucumber and celery in a greenhouse was conducted in North China Plain (NCP). It included four treatments, i.e., no N fertilizer (CK), farmers' conventional fertilization (FP), conventional fertilization rate with drip fertigation (FPD), and reduced N fertilizer rate with drip fertigation (RFPD). Results The mean annual area-scaled, yield-scaled N.sub.2O emissions and direct N.sub.2O emission factors (EF.sub.d) of FP were 36 kg N ha.sup.-1, 175 g N t.sup.-1 and 1.3%, respectively. FPD significantly reduced N.sub.2O emissions by over 25% (both in area- and yield-scaled), enhanced IWUE by 37%, and had no significant negative effects on vegetable yield or NUE. RFPD also significantly mitigated both area- and yield-scaled N.sub.2O emissions by about 45%, improved IWUE by 40% and NUE by 25%, while maintaining vegetable yield. Quadratic curves were fitted to the boundary points of ln-transformed N.sub.2O emissions against soil temperature and water-filled pore space (WFPS), with the maximum N.sub.2O losses occurring at 19.5 â or 68%. N.sub.2O emissions responded to IWUE and NUEs following an exponential (R.sup.2 = 0.71, P < 0.001) and a linear-plateau model (R.sup.2 = 0.67, P < 0.001), respectively. Conclusions Drip irrigation with reduced N fertilizer rate is a suitable agronomic practice to simultaneously mitigate N.sub.2O emissions and improve both IWUE and NUE while maintaining vegetable yield from typical greenhouse cucumber-celery fields in NCP.