不同管理措施对华北平原冬小麦田土壤CO2和N2O排放的影响研究

The Effect of Management Practices on the Emission of CO_2 and N_2O from the Winter Wheat Field in North China Plain

选文研究了不同农作管理措施--有机肥与化肥配施、秸秆还田、以及不同耕作方式(常规耕作、旋耕、免耕)等对华北平原冬小麦地土壤CO2与N2O排放的影响。研究结果表明:1)冬小麦生育期土壤CO2排放通量主要受土壤温度的影响,CO2排放通量与5cm土壤温度呈指数关系或二次抛物线关系;CO2排放主要发生在返青后,返青后到成熟期的排放量平均占小麦生育期总排放量的64.1%。2)在施用化肥的情况下适当配施有机肥,并未引起土壤CO2排放的显著增加;秸秆还田没有显著增加冬小麦生育期内的土壤CO2排放量;与常规耕作相比,旋耕使冬小麦生育期土壤CO2累积排放量有一定程度降低,免耕使土壤CO2累积排放量显著降低,冬小麦生育期旋耕和免耕处理的土壤CO2累积排放量分别是常规耕作的98.2%与84.6%。3)冬小麦生育期间的N2O排放峰主要发生在施肥后(包括基肥和追肥后),追肥后第10 d开始的近一个月内累积排放的N2O占全生育期总排放量的一半。4)基肥合理配施有机肥降低了返青拔节期单施化肥引起的短期N2O排放通量高峰;秸秆还田没有显著增加冬小麦生育期内的土壤N2O排放量;旋耕与常耕对土壤N2O排的影响差异不显著,免耕处理比常规耕作使土壤N2O排放通量显著降低,免耕处理的土壤N2O累积排放量是常规耕作的77.0%。

The effect of different management practices, including amendment of manure with fertilizers, straw incorporation, tillage method （conventional tillage, rotated tillage, No-tillage）, on the emission of soil CO2 and N2O from the winter wheat field in the North China Plain was studied. The results showed that： （1） The emission flux of CO2 from the winter wheat field was mainly controlled by the soil temperature, and the relationship between soil temperature and CO2 flux could be described using exponential or quadratic parabola equation. The emission peak happened mainly from reviving to mature period at the later spring and early summer season, and the accumulated CO2 emission in the this period accounted for 64.1% of total CO2 emission in the winter wheat growth period. （2） Appropriate amendment of manure with fertilizers did not significantly result in the increase of soil CO2 emission. Incorporation of straw did not obviously cause the increase of soil CO2 emission either. Compared with the conventional tillage method, the soil CO2 emission of rotated tillage treatment showed slightly decrease of CO2 emission （which was 98.2% of that under conventional tillage condition） and the No-tillage significantly decrease the soil CO2 emission （which was 84.6% of that under the conventional tillage condition）. （3） The N2O emission peak in the winter wheat growth period mainly occurred just after the application of nitrogen fertilizer （both base application and the topdressing）, and the accumulated N2O emission during the one month period since 20 days of topdressing accounted for half of the total emission in the whole winter wheat period. （4） Appropriate amendment of manure with chemical nitrogen fertilizer could reduce the emission flux of higher peak which occurred just after the topdressing. Incorporation of straw did not result in the increase of N2O emitted from the winter wheat field. Rotated tillage did not cause obvious difference of accumulated N2O emission, while No-tillage decreased the accumulated N2O emission significantly by 77.0%.