秸秆直接还田与燃烧后还田对冬小麦田NO排放的影响  

Effects of direct straw return and burning ash amendment on soil NO fluxes in a winter wheat cropland

作　　者：苏媛媛 王艳强[3] 梅宝玲 姚志生[2] SU Yuanyuan;WANG Yanqiang;MEI Baoling;YAO Zhisheng(School of Ecology and Environment,Inner Mongolia University,Huhhot 010021,China;State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry,Institute of Atmospheric Physics,Chinese Academy of Sciences,Beijing 100029,China;Institute of Mountain Hazards and Environment,Chinese Academy of Sciences,Chengdu 610041,China)

机构地区：[1]内蒙古大学生态与环境学院,呼和浩特010021 [2]中国科学院大气物理研究所大气边界层物理和大气化学国家重点实验室,北京100029 [3]中国科学院水利部成都山地灾害与环境研究所,成都610041

出　　处：《清华大学学报（自然科学版）》2021年第12期1462-1471,共10页Journal of Tsinghua University(Science and Technology)

基　　金：国家自然科学基金项目(41675144,41977282)。

摘　　要：为减少秸秆燃烧所造成的大气污染,国家鼓励农民施行秸秆直接还田措施。但是,秸秆还田会改变多种土壤理化因素,引起碳氮生物地球化学过程发生变化,进而可能改变环境污染性气体一氧化氮(NO)的产生和排放。为了探究秸秆不同还田方式如何影响冬小麦田NO排放,该文依托紫色土农业生态试验站的秸秆不同还田方式长期试验平台(2005年—),采用静态暗箱-化学发光法对农民常规施肥(NPK)、常规施肥+秸秆直接还田(NPK+SR)和常规施肥+秸秆燃烧后还田(NPK+SB)以及不施肥对照(CK)处理下的NO排放通量及辅助因子进行了一个完整生长季(2016年10月至2017年5月)观测。结果表明,各施肥处理下较高的NO排放均出现在施肥后1~2周内,与土壤无机氮含量变化趋势基本一致。在整个小麦生长季,土壤无机氮,尤其铵态氮(NH_(4)^(+))浓度是NO季节变化动态的关键控制因子,二者呈显著线性正相关关系。与NPK相比,NPK+SB并未明显影响NO季节排放量,而NPK+SR却显著抑制了NO季节排放量的49.0%。基于施肥处理与CK处理之间NO排放量的差异,NPK、 NPK+SB和NPK+SR处理的NO直接排放系数分别为0.33%、 0.32%和0.15%。此外,与NPK相比,NPK+SB和NPK+SR提高了作物的氮肥利用效率,从而分别增加了小麦籽粒产量的18.9%和15.8%。依据土壤NO排放和小麦产量相结合的指标(即NO排放强度), NPK+SB比NPK显著降低了NO排放强度的19.7%,而NPK+SR比NPK+SB又进一步显著减少了NO排放强度的45.6%。因此,对于紫色土冬小麦田来说,秸秆直接还田处理是一种较好的优化施肥管理方式,可以同时满足保障粮食安全和减少大气环境污染性气体NO排放。Returning straw to the soil rather than burning it can reduce negative environmental impacts such as air pollution. However, the incorporation of straw into the soil changes the soil physico-chemical properties, the biogeochemical C and N cycles and the associated environmental pollutant nitric oxide(NO) production and release. This study assessed how the soil NO fluxes respond to different methods of straw return in a winter wheat cropland. The assessment was based on measurements of the NO fluxes and auxiliary variables throughout the entire wheat-growing season(from October, 2016 to May, 2017) in a long-term purplish soil experimental platform with conventional fertilization(NPK), conventional fertilization + direct straw return(NPK+SR) and conventional fertilization + burning ash amendment(NPK+SB) as well as no nitrogen application as a control(CK) using a static opaque chamber and chemiluminescent analysis. The results showed pronounced NO peak fluxes with the fertilized treatments within the first 1-2 weeks after basal fertilization, which is comparable to the temporal trend of the soil mineral nitrogen. Thus, soil mineral nitrogen, specifically the soil ammonium(NH_(4)^(+)) concentration, is the key factor controlling the NO flux variations with soil NO fluxes strongly positively correlated with soil NH_(4)^(+)concentrations. In comparison to NPK, NPK+SB did not significantly affect seasonal NO emissions, while NPK+SR greatly inhibited seasonal NO emissions by 49.0%. When the control emissions were deducted as background emissions, the direct NO emission factors were estimated to be 0.33%, 0.32% and 0.15% for NPK, NPK+SB and NPK+SR, respectively. Besides, both NPK+SB and NPK+SR treatment improve crop nitrogen use efficiency, and consequently enhancing wheat grain yields by 18.9% and 15.8%, respectively, comparing with NPK. The yield-scaled emissions(i.e., NO emission intensity) of NPK+SB were 19.7% less than those of NPK. Direct incorporation of the straw into the soil instead of burning further reduced th

关 键 词：NO排放 排放系数 小麦田 秸秆还田 秸秆燃烧 

分 类 号：X511[环境科学与工程—环境工程]