不同耕作措施下土壤N_2O排放及其农学效率  

Soil N_2O emission and its agronomic efficiency under different tillage

作　　者：许艳艳[1,2] 武兰芳[1] 李彬彬[1] 丘清燕[1,2] 秦越[1,2] 

机构地区：[1]中国科学院地理科学与资源研究所生态系统网络观测与模拟重点实验室,北京100101 [2]中国科学院大学,北京100049

出　　处：《中国生态农业学报》2015年第11期1349-1358,共10页Chinese Journal of Eco-Agriculture

基　　金：国家自然科学基金项目(31271675);国家科技支撑计划课题(2013BAD05B03)资助~~

摘　　要：为评价不同耕作措施下华北平原农田土壤N2O排放及其农学效率,通过设置常规耕作秸秆还田（CT＋）、常规耕作无秸秆还田（CT＋）、免耕秸秆还田（NT＋）、免耕无秸秆还田（NT？）4个处理田间定位试验,采用静态箱？气相色谱法测定分析了连续3个小麦生长期的表层土壤N2O排放及其主要相关因子,同时测定了小麦产量与氮吸收量等相关指标。结果表明：在4个处理下,小麦生长期内表层土壤N2O排放动态基本一致,而土壤N2O累积排放量却存在显著差异,而且耕作方式与秸秆还田存在显著的互作效应。在常规耕作和免耕措施下,单位面积土壤N2O累积排放量均表现为秸秆还田土壤显著高于无秸秆还田土壤,CT＋和NT＋分别比CT？和NT？高26.2%和74.6%;在无秸秆还田条件下,土壤N2O排放量表现为常规耕作比免耕高42.4%。相关分析表明,土壤N2O排放通量与地下5 cm土壤温度、土壤孔隙充水率（WFPS）之间呈显著正相关关系,与土壤溶解性有机氮（DON）含量之间呈显著负相关关系。利用农学效率指标度量N2O排放量时可知,虽然小麦籽粒产量和氮肥偏生产力在各处理间没有达到显著性差异,但每生产1 kg小麦籽粒表层土壤N2O排放量为0.18--0.73 g N2O-N,每投入1 kg氮素表层土壤N2O排放量为5.1--18.0 g N2O-N,处理间存在显著差异;与单位面积土壤N2O排放量表现一致,单位籽粒产量N2O排放量和单位氮素投入N2O排放量均表现为无论是常规耕作还是免耕措施,秸秆还田土壤均显著高于秸秆不还田土壤,在秸秆不还田条件下,常规耕作土壤均显著高于免耕土壤。总之,免耕是有效减少土壤N2O排放的一种耕作措施。Cultivated land soil is regarded as an important source of N2 O emission that is affected by farming practices. To determine effects of tillage and crop residues management on soil N2 O emission and it＇s agronomic efficiency on the North China Plain, a field experiment was carried out, which contained 4 treatments with 3 replications. The 4 treatments were conventional tillage with crop residues incorporation to soil（CT＋） and without crop residues incorporation to soil（CT-）, no-tillage with crop residues mulching（NT＋） and without crop residues mulching（NT-）. During the field experimentation soil N2 O emissions at soil/atmosphere interface were sampled and analyzed by using static chamber-Gas Chromatography（GC） method in continuous 3 wheat growth seasons; meanwhile, the primary related factors with N2 O emission were also investigated and analyzed. The results showed that the dynamic changes of soil N2 O emission during wheat growth were similar but the cumulative N2 O emissions were significantly different under 4 treatments and, the interactive effect between tillage and crop residues management was significant. The cumulative N2 O emission per unit area under CT＋ and NT＋ were higher than those under CT？ and NT？ by 26.2% and 74.6%, respectively, and CT？ treatment emitted 42.4% more N2 O than NT？treatment. The soil N2 O emission was greatly influenced by soil temperature and soil moisture. The correlation analysis indicated that there was a significant positive correlation between soil N2 O emission and both soil temperature at 5 cm depth soil and water filled pore space（WFPS）, while there was a significantly negative relation between soil N2 O emission and dissolved organic nitrogen（DON）. When assessing soil N2 O emission in relation to crop productivity expressed as above-ground N uptake（i.e. yield-scaled and nitrogen input-scaled N2 O emission）, the soil N2 O emissions per kilogram grain yield were 0.18？0.73 g N2O-N and per kilogram nitrogen input were 5.1？

关 键 词：土壤 N2O排放 耕作措施 秸秆还田 农学效率 

分 类 号：X712[环境科学与工程—环境工程]