水土保持通报2023，Vol.43Issue(6)：106-114,9.DOI:10.13961/j.cnki.stbctb.2023.06.014
不同水分条件下土壤N2O排放的动力学方程模拟
Simulation of Soil N2O Emissions Under Different Soil Moisture Conditions by Using Mixed Dynamic Equation
摘要
Abstract
[Objective]Soil moisture has an important impact on N2O emissions.This study attempted to simulate the cumulative process of soil N2O emission under different soil moisture conditions by using a mixed dynamic equation,and to analyze the influence of soil water on N2O production pathway and its variation rule in order to provide theoretical and practical guidance for reducing N2O gas emissions through improving soil management.[Methods]Soil N2O emission characteristics,the dynamics of ammonium and nitrate nitrogen content,and oxygen consumption were studied under different soil moisture conditions[40％water-holding capacity(WHC),60％WHC,80％WHC,100％WHC,and flooded].[Results]① TheN2O emission rates reached maximum values at 24 h.Emissions from the flooded treatment[3.46 μg/(kg·h)]were 54.5-178.9 times greater than from the other treatments.② The cumulative emission of soil N2O increased with increasing incubation time,and the rapid rise stage occurred in the first 48 h for the flooded treatment.The rapid rise stage occurred in the first 96 h for other treatments.The cumulative N2O emissions for soil under the flooded treatment(44.6 μg/kg)were 67.1,29.2,20.8,and 10.4 times greater than under 40％ WHC,60％ WHC,80％ WHC and 100％ WHC,respectively,at the end of incubation.③ Except for the coefficient of determination(R2)of 0.878 for the pseudo-second-order dynamic equation under the flooded treatment,all coefficients of determination were greater than 0.920 for all dynamic equations under all soil moisture treatments.The denitrification process accounted for 9.3％～13.2％ of the N2O emissions,and the nitrification process accounted for 86.8％～90.7％ of the N2O emissions at the initial 24 h of incubation.At the end of incubation(480 h),the denitrification process accounted for 37.8％～47.5％ of the N2O emissions,and the nitrification process accounted for 52.5％～62.2％ of the N2O emissions.[Conclusion]The higher the soil moisture content,the greater the emission of N2O,and an emission rate pulse appeared at 24 h.N2O was mainly generated by denitrification under flooded conditions.N2O was mainly generated by nitrification under the 40％～100％ WHC conditions.The mixed dynamic equation was able to well simulate the cumulative emission process of soil N2O during the incubation experiment,and can be used to distinguish the amount and proportion of N2O emissions occurring by denitrification and nitrification processes.These results provide a new idea and method for studying the pathways of soil N2O production and emission.The results need to be further verified by field experiments and isotope tracing methods etc.关键词
N2O排放/土壤水分/动力学方程/硝化作用/反硝化作用Key words
N2O emission/soil moisture/dynamic equation/nitrification/denitrification分类
资源环境引用本文复制引用
唐坤,郑艺欣,赵成政,段淑方,高明霞,冯浩,孙本华..不同水分条件下土壤N2O排放的动力学方程模拟[J].水土保持通报,2023,43(6):106-114,9.基金项目
国家重点研发计划项目"黄土高原旱作适水改土与产能提升技术模式及应用"(2021YFD1900700) （2021YFD1900700）
高等学校学科创新引智计划项目(B12007) （B12007）
