Simulation of Soil N2O Emissions Under Different Soil Moisture Conditions by Using Mixed Dynamic Equation
Journal Title: Bulletin of Soil and Water Conservation - Year 2023, Vol 43, Issue 6
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 The N2O 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.
Authors and Affiliations
Kun Tang, Yixin Zheng, Chengzheng Zhao, Shufang Duan, Mingxia Gao, Hao Feng, Benhua Sun
Keywords
Related Articles
- EP ID EP762752
- DOI 10.13961/j.cnki.stbctb.2023.06.014
- Views 12
- Downloads 0
Experimental Research on Strength of Root-Soil Composites and Their Nonlinear Characteristics
[Objective] A nonlinear failure criterion of root-soil composites and the nonlinear characteristics of root-soil composites was studied combining with the strength of root-soil composites under three root content conditi...
Effects of Different Land Utilization Methods on Soil Aggregate Stability and Organic Carbon Content in Alpine Grassland
[Objective] The soil aggregate stability and differences in organic carbon distribution for Bayanbulak alpine grassland, Xinjiang Wei Autonomous Region under different land utilization methods were analyzed in order to p...
Ecological Protection Effects Provided by Sand Barriers in a Grassland Mining Area
[Objective] The wind protection effectiveness of different sand barriers and their effects on surface soil particle size composition, soil nutrients and vegetation growth werer studied in order to provide a theoretical b...
Effects of Winter Irrigation on Soil Water-heat-salt Migration and Crop Growth During Freezing-Thawing Period in Qingtongxia Irrigation District of Ningxia
[Objective] The effects of winter irrigation on soil water-heat-salt migration and crop growth during the freezing-thawing period were analyzed in order to provide a scientific basis for controlling soil salinization, an...
Response of Soil and Water Conservation Ecosystem Service Value to Land Use Type at Anjiagou Watershed in Dingxi City
[Objective] The ecosystem service value of different land use types at Anjiagou watershed in Dingxi City, Gansu Province was quantitatively determined in hilly and gully regions of the Yellow River basin from 2005 to 202...