CAJ | 학술논문

为探讨日光温室黄瓜—番茄种植体系内N2O排放动态变化及其对不同氮水平的响应规律，采用密闭静态箱法，研究了常规氮量（黄瓜季1200 kg/hm2，番茄季900 kg/hm2）、比常规氮量减25%（黄瓜季900 kg/hm2，番茄季675 kg/hm2）、减50%（黄瓜季600 kg/hm2，番茄季450 kg/hm2）以及不施氮对日光温室土壤N2O排放的影响。结果表明，温度是影响日光温室土壤N2O排放强度的重要因素，4－10月（平均气温为27.4℃）的N2O排放通量最高达818.4μg/(m2·h)；而2－3月（平均气温15.1℃）以及11－12月（平均气温14.7℃）期间的N2O排放通量最高仅为464.5μg/(m2·h)，比4－10月的N2O排放峰值降低了43.2%。N2O排放峰值在氮肥追施后5 d内出现，N2O排放量集中在氮肥施用后7 d内，可占整个监测期（271 d）排放量的64.7%～67.8%。施氮因增加了土壤硝态氮含量而引起N2O排放爆发式增长，0～10 cm土壤硝态氮含量与N2O排放量呈指数函数关系（P<0.01）。日光温室黄瓜—番茄种植体系内的N2O排放量为0.99～9.92 kg/hm2，其中75.6%～90.0%由施氮造成。与常规氮用量相比，氮减量25%和50%处理的N2O排放量分别降低了40.4%和59.3%，总产量却增加4.9%和7.4%。综上所述，合理减少氮用量不仅可显著降低日光温室土壤N2O排放，而且不会引起产量的降低。该研究为日光温室蔬菜生产构建科学合理的施氮技术及估算中国设施农田温室气体排放量提供参考。
위탐토일광온실황과—번가충식체계내N2O배방동태변화급기대불동담수평적향응규률，채용밀폐정태상법，연구료상규담량（황과계1200 kg/hm2，번가계900 kg/hm2）、비상규담량감25%（황과계900 kg/hm2，번가계675 kg/hm2）、감50%（황과계600 kg/hm2，번가계450 kg/hm2）이급불시담대일광온실토양N2O배방적영향。결과표명，온도시영향일광온실토양N2O배방강도적중요인소，4－10월（평균기온위27.4℃）적N2O배방통량최고체818.4μg/(m2·h)；이2－3월（평균기온15.1℃）이급11－12월（평균기온14.7℃）기간적N2O배방통량최고부위464.5μg/(m2·h)，비4－10월적N2O배방봉치강저료43.2%。N2O배방봉치재담비추시후5 d내출현，N2O배방량집중재담비시용후7 d내，가점정개감측기（271 d）배방량적64.7%～67.8%。시담인증가료토양초태담함량이인기N2O배방폭발식증장，0～10 cm토양초태담함량여N2O배방량정지수함수관계（P<0.01）。일광온실황과—번가충식체계내적N2O배방량위0.99～9.92 kg/hm2，기중75.6%～90.0%유시담조성。여상규담용량상비，담감량25%화50%처리적N2O배방량분별강저료40.4%화59.3%，총산량각증가4.9%화7.4%。종상소술，합리감소담용량불부가현저강저일광온실토양N2O배방，이차불회인기산량적강저。해연구위일광온실소채생산구건과학합리적시담기술급고산중국설시농전온실기체배방량제공삼고。
Nitrous oxide (N2O) is one of the most important greenhouse gases contributing to global warming and depletion of the stratospheric ozone layer. Arable land with nitrogen fertilizer application is one of the major sources of N2O emission, and the nitrogen fertilizer rate in greenhouse vegetable field is higher than that in farmland in China. However, few studies have measured N2O emissions from solar greenhouse vegetable fields, especially in cucumber-tomato rotation system. In order to identify the annual dynamic of greenhouse soil N2O emissions and investigate the impacts of nitrogen application rate on N2O emissions, the closed static chambers method was used in cucumber-tomato rotation system in greenhouse in the Northern Plain of China. The study included four nitrogen treatments, traditional nitrogen rate (cucumber, 1200 kg/hm2; tomato, 900 kg/hm2), reduced by 25% (cucumber, 900 kg/hm2; tomato, 675 kg/hm2) and 50% (cucumber, 600 kg/hm2; tomato, 450 kg/hm2), and a control (no N application). Results showed that temperature was an important factor affecting the N2O emission intensity in greenhouse. The highest of N2O fluxes was 818.4μg/(m2·h) occurred from April to Oct., when the average of air temperature and soil temperature were 27.4℃and 26.1℃, respectively. While N2O fluxes was 464.5 μg/(m2·h) occurred from Feb. to March (average air temperature=15.1℃, average soil temperature=15.0℃) and Nov. to Dec. (average air temperature=14.7℃and average soil temperature=13.7℃), this was significantly lower than that from April to Oct. Compared to the N2O flux from April to Oct., there was a 43.2%reduction in N2O fluxes from Feb. to March and Nov. to Dec. The peak of N2O emissions occurred in the first five days after topdressing of urea. The N2O emission occurred most in the first seven days after urea topdressing, which accounted for 64.7%-67.8% of total emissions during the 271 d study period. Soil moisture was not a limiting factor on N2O fluxes in greenhouse cucumber and tomato fields, because the soil water content was suitable (water filled pore space of 40.0%to 66.6%) and fertilization was usually followed by irrigation in the experiment. N2O emission increased drastically with an increasing in soil nitrate content after nitrogen application, and there was an exponential relationship between N2O emission fluxes and 0-10 cm soil nitrate content (P<0.01). Compared to traditional nitrogen rate,N2O flux peaks reduced by 40.4%and 59.3%when the nitrogen rate was decreased by 25% and 50%, respectively. The cumulative N2O emissions were 0.99-9.92 kg/hm2 in the cucumber-tomato rotation system, of which 50.5%-56.9% was from cucumber growing season. Taking N2O emissions from the N0 treatment as the background emissions, the annual N2O emission factors of nitrogen input were 0.29%-0.43% during the cucumber and tomato growth period, increasing gradually with the nitrogen application rates. About 75.6%to 90.0%of the N2O emissions were caused by nitrogen application in greenhouse vegetable fields. Less N2O emissions were produced when less nitrogen fertilizer was used. Compared to the traditional nitrogen rate treatment, cumulative N2O emissions of minus 25% and 50% nitrogen compared to traditional treatment were reduced by 40.4%and 59.3%. At the same time, the decreased nitrogen rate increased the total yield by 4.8% and 7.4%. In summary, for present solar greenhouse vegetable production in the North China Plain, appropriate reduction of nitrogen application rate can significantly reduce the N2O emissions without any negative effect on yield. The research provides a reference for nitrogen management for greenhouse vegetable production and fills the information gap for N2O emission from greenhouse under current management practice in China.