大气CO_(2)浓度升高背景下秸秆还田对小麦土壤氮矿化的影响  

Effects of Straw Return on Nitrogen Mineralization in Wheat Soil under Elevated CO_(2)Concentration

作　　者：杨净 王紫芊 来夏萱 郝兴宇[1] 宗毓铮[1] 张东升 史鑫蕊 李萍[1] YANG Jing;WANG Ziqian;LAI Xiaxuan;HAO Xingyu;ZONG Yuzheng;ZHANG Dongsheng;SHI Xinrui;LI Ping(College of Agriculture,Shanxi Agricultural University,Taigu,Shanxi 030801;Maize Research Institute,Shanxi Agricultural University,Xinzhou,Shanxi 034000)

机构地区：[1]山西农业大学农学院,山西太谷030801 [2]山西农业大学玉米研究所,山西忻州034000

出　　处：《核农学报》2024年第11期2228-2236,共9页Journal of Nuclear Agricultural Sciences

基　　金：中央引导地方科技发展资金项目(YDZJSX2022A041);山西省基础研究计划青年科学研究项目(20210302124656);山西农业大学农学院研究生实践创新计划项目(2023YCX40)。

摘　　要：为探讨小麦土壤氮矿化对CO_(2)浓度升高、秸秆还田及其交互作用的响应,本研究利用人工控制气候室设置2种CO_(2)浓度处理CK(CO_(2)浓度为400μmol·mol^(−1))、EC(CO_(2)浓度为600μmol·mol^(−1)),3种秸秆处理:秸秆不还田(R)、秸秆掺入(I)、秸秆覆盖(M),测定小麦土壤理化性质、碳氮相关酶活性;通过为期35 d的室内培养试验,分析土壤硝态氮、铵态氮含量动态变化和净氮矿化速率等。结果表明,培养35 d后与秸秆不还田相比,两种秸秆还田方式均增加了土壤碳氮有效性,秸秆掺入和秸秆覆盖处理土壤净硝化速率在两种CO_(2)浓度处理下分别平均增加0.76和0.55 mg·kg^(-1)·d^(-1)。3种秸秆处理方式中,以秸秆掺入土壤净矿化速率最大;秸秆覆盖土壤净氨化速率较低,导致其净矿化速率低于秸秆掺入。与CK相比,CO_(2)浓度升高使土壤无机氮含量平均下降8.1%,土壤氮矿化量平均降低14.98 mg·kg^(-1)。与CK相比,CO_(2)浓度升高下秸秆还田使土壤无机氮含量增加74.2 mg·kg^(-1),主要是由于土壤硝态氮含量增加了73.8 mg·kg^(-1),导致土壤净硝化速率提高了0.57 mg·kg^(-1)·d^(-1);CO_(2)浓度升高下土壤净氨化速率整体下降,其中秸秆覆盖下降幅度较大,导致其净氮矿化速率低于CK。综上,CO_(2)浓度升高下秸秆还田增加了土壤氮的可利用性,其中秸秆覆盖提高了土壤氮固持能力,减少了氮素淋失,秸秆掺入增加了土壤氮矿化,可提供更多无机氮以供作物利用。本研究为未来气候变化背景下选择适宜秸秆还田措施以维持土壤供氮潜力提供了理论依据和技术支持。To investigate the response of soil nitrogen mineralization in wheat to elevated CO_(2)concentration,straw return,and their interaction,the study was set up two CO_(2)concentrations[CK(400μmol·mol-1 of CO_(2)concentration),EC(600μmol·mol^(−1) of CO_(2)concentration)],and three straw return methods[straw removal(R),straw incorporation(I),straw mulching(M)]in the controlled climate chamber.The soil physical and chemical properties,and the carbon and nitrogen related enzymes activities were measured.Soil nitrate,ammonium contents,and net nitrogen mineralization rate were analyzed through 35 days incubation experiment.The results showed that:compared with straw removal,straw incorporation and mulching increased soil carbon and nitrogen availability,and increased the net nitrification rates by 0.76 and 0.55 mg·kg^(-1)·d^(-1),respectively.Among the three straw return methods,straw incorporation had the highest net mineralization rate,while straw mulching had a lower net mineralization rate due to a lower net ammonification rate.Elevated CO_(2)concentration decreased soil nitrogen availability by 8.1%,resulting in a 14.98 mg·kg^(-1)decrease in soil nitrogen mineralization.Compared with the control,straw return under elevated CO_(2)concentration increased the soil inorganic nitrogen by 74.2 mg·kg^(-1),due to the increased nitrate by 73.8 mg·kg^(-1),which led to an increase of 0.57 mg·kg^(-1)·d^(-1)in the soil net nitrification rate,but it decreased the net ammonification rate.The soil net ammonification rate under straw mulching decreased significantly,resulting in a lower net nitrogen mineralization rate than the control.In conclusion,straw return under elevated CO_(2)concentration increased the availability of soil nitrogen.Straw mulching improved soil nitrogen immobilization and reduced nitrogen leaching.Straw incorporation increased soil nitrogen mineralization,thus providing more inorganic nitrogen for crop utilization.This study provided theoretical basis and technical support for maintaining soil nitr

关 键 词：CO_(2)浓度升高 秸秆还田 小麦土壤 氮矿化 

分 类 号：S512.1[农业科学—作物学] S153