华北典型冬麦区农田氧化亚氮通量

FLUX OF NITROUS OXIDE ON TYPICAL WINTERWHEAT FIELD IN NORTHERN CHINA

本工作在华北典型冬麦区测定了小麦返青后各生育期间的氧化亚氮通量。在施肥和不施肥的小麦地和苜蓿地进行了通量测量,初步考察了施肥、浇水、地温等对通量的影响。在土壤相同的条件种植苜蓿和小麦的农田通量值相近似。施肥、浇水和地温增高都增大通量值。而小麦生长后期,尽管地温增高,通量值却逐渐下降,这与土壤速效氮耗竭有关。同时,讨论了土壤中产生氧化亚氮的机制和实验结果,并提出今后工作设想。

Nitrous oxide flux has been studied on a typical winter wheat field in northern China(37°54′N,114°42′E).Gaseous samples were collected from a sampling chamber of 1 × 1 × 1m3 settled on the field and analysed with an eletron capture detector gas chro-matography. The measurement schedule coincided with major biological phenomena of the winterwheat growth in fertilized and unfertilized field. For comparison measurement was performed also in alfalfa field. The effects of fertilization,irrigation, soil temperature on flux were studied.It is shown that all of these factors are conducible to the emission of nitrous oxide from the soil, with the similar soil the fluxes on winterwheat and alfalfa farmland do not have obvious difference between each other. Diel variability of fluxes shows that there is positive correlation between the fluxes and soil temperatures. The fluxes at different situation variate in a range of 2-46μgN/m2·h.Mechanism of nitrous oxide production in the soil is considered too. Further research on monitoring and modeling is needed.