田间管理对华北平原冬小麦产量土壤碳及温室气体排放的影响

Field Managements Affect Yield,Soil Carbon,and Greenhouse Gases Emission of Winter Wheat in North China Plain

选取华北平原冬小麦为研究对象,针对(1)秸秆移除;(2)秸秆表覆;(3)免耕;(4)秸秆深施;(5)施农家肥这5种典型的田间管理,使用农田自动温室气体测定系统对冬小麦农田全生育期进行了原位长期观测,并采用13C自然丰度法对土壤碳的转化进行了监测,同时对冬小麦产量及生物量、土壤有机碳的变化进行了监测。结果表明,冬小麦产量及生物量高低顺序为施农家肥、秸秆深施、秸秆表覆、秸秆移除和免耕,而且土壤有机碳的更新也有同样的趋势;施农家肥能显著增加土壤有机碳而秸秆移除和免耕则会导致土壤有机碳的轻微下降;冬小麦甲烷的排放或吸收只占总增温潜势的不到1%,在进行统计总排放当量时基本可以忽略,N2O在总排放当量中的比例在2.55%～11.62%范围内;N2O的大量排放主要来自于拔节期及开花期,秸秆移除、施农家肥和秸秆深施会导致N2O排放在总当量中的份额增加至10%左右,而秸秆覆盖和免耕N2O排放在总排放当量中的份额只有3%左右,冬小麦农田总的温室气体排放88%以上来自于CO2的排放,特别是秸秆表覆和免耕95%以上来自土壤碳的损失而释放的CO2。总体来看,秸秆深施能保证较高的产量,减少碳的损失,增加土壤碳并产生相对较少的总温室气体排放量,是较好的固碳减排方式。

Five dominant field managements in winter wheat field in North China Plain（NCP）are chosen as treatments. That is （ 1 ）residue removal（TRR）, （2）residue mulch（TRM）, （ 3 ）No Tillage（TNT）, （4）residue incorporation （TRI）and （5）manure（TM）. Using automatic chamber and GC measurement system in the field to monitor the greenhouse gases emitted from the field during whole season, by ^13C nature abundant method to monitor carbon turnover, winter wheat yield and soil organic carbon is also been monitored. The results showed that：The treatment yield in descending order is TM, TRI, TRM, TNT and TRR respectively, same tendency with the soil organic carbon （SOC）renewing percentage. TM can more significantly increase yield and SOC, while TRR and TNT can slightly drop the yield and SOC. The methane from winter wheat field is less than 1% to total GHG emission and maybe neglectable, and N2O account for 2.55%-11.62% to total GHG emission in winter wheat field. The major N2O emission start from jointing stage and TNT, TM, TRI has higher N2O emission around 10% of total GHG emission, while TRR, TRR has lower N2O emission around 3% of total GHG emission. CO2 account for over 88% total GHG emission in winter wheat field and for TRM and TNT the portion is over 95%. In general comparison, TRI has relatively higher grain yield, SOC renewed and SOC increasing, and relatively lower GHG emission. It is a good method for carbon sequestration and GHG abatement.