摘要
过量施氮可破坏农田土壤结构,增加温室气体排放量。为揭示不同施氮量对土壤团聚体和N_(2)O排放的影响,于2018—2020年基于氮肥定位试验,设置秸秆原位还田条件下施氮0(N_(0))、120(N_(120))、180(N_(180))、240(N_(2)40)、300(N_(300))、360 kg·hm^(-2)(N_(360))6个处理,研究不同施氮量对麦田土壤N_(2)O排放、土壤充水孔隙度(WFPS)、土壤温度、硝态氮、铵态氮含量、水稳性团聚体的组成及稳定性的影响。结果表明:土壤N_(2)O排放量与氮肥用量之间呈显著正相关关系,WFPS与施氮量之间无显著相关关系,0~10 cm土壤温度随氮肥施用量的增加而显著降低,土壤硝态氮、铵态氮含量与氮肥施用量间存在显著正相关关系。随氮肥施用量的增加,直径>2 mm的水稳性团聚体含量降低,直径<0.5 mm的水稳性团聚体含量增加,土壤水稳性团聚体的粒径也逐渐减小。氮肥施用量与团聚体平均重量直径(MWD)、几何平均直径之间呈显著负相关关系,但与分形维数之间并无显著相关性。MWD(x)与N_(2)O排放通量(y)之间的拟合方程为:y=3928.3e^(-2.171x)(R^(2)=0.55,P<0.001),表明当MWD减小时,N_(2)O排放量将会剧烈升高。可见,麦田施氮量的增加会降低0~10 cm土壤温度,增加土壤硝态氮和铵态氮含量,减小耕层土壤水稳性团聚体的平均粒径,降低团聚体的稳定性,增加N_(2)O的排放量。
Excessive nitrogen application would deteriorate soil structure and increase greenhouse gas emission.We set up six treatments,i.e.,N_(0),N_(120),N_(180),N_(2)40,N_(300)and N_(360)(nitrogen application rates of 0,120,180,240,300 and 360 kg·hm^(-2),all straws returned into the field in situ)in the nitrogen fertilizer experimental site to investigate the effects of different nitrogen application rates on soil N_(2)O emission,soil water-filled porosity(WFPS),soil temperature,nitrate and ammonium contents,composition and stability of water stable aggregates in winter wheat filed in 2018-2020.The results showed that there was a significant positive correlation between soil N_(2)O emission and nitrogen application rate.There was no correlation between WFPS and nitrogen application rate.Soil temperature in the 0-10 cm layer decreased significantly with the increases of nitrogen application rates.There was a significant positive correlation between nitrate and ammonium contents and nitrogen application rate.With the increases of nitrogen application rates,the content of water stable aggregates with diameter>2 mm decreased,while that of water-stable aggregates with diameter<0.5 mm increased.The particle size of soil water-stable aggregates also decreased gradually.There was a significant negative correlation between nitrogen application rate with mean weight diameter(MWD)and geometric mean diameter,while no correlation with fractal dimension.The fitting equation between MWD and N_(2)O emission flux was y=3928.3e^(-2.171x)(R^(2)=0.55,P<0.001),indicating that N_(2)O emission increased markedly as MWD decreasing.The increases in nitrogen application rate reduced soil temperature in the 0-10 cm layer,increased nitrate and ammonium contents,decreased the average particle size of soil water stable aggregates,and the stability of soil aggregates,and increased soil N_(2)O emission.
作者
陈津赛
孙玮皓
王广帅
Abubakar Sunusi Amin
高阳
CHEN Jin-sai;SUN Wei-hao;WANG Guang-shuai;Abubakar Sunusi Amin;GAO Yang(Farmland Irrigation Research Institute,Chinese Academy of Agricultural Sciences/Key Laboratory of Crop Water Requirement and Regulation,Ministry of Agriculture and Rural Affairs,Xinxiang 453002,Henan,China;Graduate School of Chinese Academy of Agricultural Sciences,Beijing 100081,China)
出处
《应用生态学报》
CAS
CSCD
北大核心
2021年第11期3961-3968,共8页
Chinese Journal of Applied Ecology
基金
国家自然科学基金项目(51879267,51679242)
财政部和农业农村部国家现代农业产业技术体系项目(CARS-03)
中央级科研院所基本科研业务费项目(FIRI20210104)资助。
关键词
冬小麦
施氮
土壤理化性质
N_(2)O
水稳性团聚体
winter wheat
nitrogen application
soil physicochemical property
N2O
water stable aggregate
