Variations of leachate CO2 and N2O concentrations on typical cultivated and natural hillslopes in southeastern hilly area of China
Variations of leachate CO2 and N2O concentrations on typical cultivated and natural hillslopes in southeastern hilly area of China
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DOI：
10.1016/j.agee.2022.108140
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发表时间：
2022-11
期刊：
影响因子：
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通讯作者：
Fei Liu;Yongwu Wang;Q. Zhu;X. Lai;K. Liao;Changqiang Guo
中科院分区：
文献类型：
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作者：
Fei Liu;Yongwu Wang;Q. Zhu;X. Lai;K. Liao;Changqiang Guo
与土壤-大气界面的排放相比，人们对溶解在土壤水中并通过地下水流迁移的温室气体了解甚少。2019年9月至2022年2月，在中国东南部丘陵区的茶园（TG）山坡（耕作）和竹林（BF）山坡（自然植被）上监测了渗滤液CO2和N2 O浓度。在TG山坡上，渗滤液CO2和N2 O浓度分别为1.07至9.83 mg C L− 1和0.32至11.74 μg N L−1，而在BF山坡上，它们分别为0.64至25.95 mg C L− 1和0.23至5.68 μg N L−1。在两个山坡上，渗滤液CO2浓度在夏季最大，而在冬季最低。在TG坡地上，渗滤液N2 O浓度最高值出现在春季，最低值出现在夏季，而在BF坡地上，渗滤液N2 O浓度最高值出现在秋季，最低值出现在冬季。在这两个山坡上，土壤温度，降水量在过去的15天，和基质电位呈正相关的渗滤液CO2浓度，但不相关的渗滤液N2 O浓度。土壤含水量与渗滤液CO2和N2 O浓度均呈正相关，与地下水位埋深呈负相关。TG坡面淋滤液中总无机氮和土壤中总无机氮含量与淋滤液中N2 O含量呈正相关，而BF坡面淋滤液中总无机氮和土壤中总无机氮含量与淋滤液中N2 O含量无相关性。渗滤液CO2和N2 O浓度的空间变异主要受土地覆被、地形属性（坡度、海拔）、土壤粒径分布、容重和土壤有机质含量的影响。本研究的结果补充了土壤水溶解的CO2和N2 O在耕地和自然植被覆盖的知识。需要进一步的研究来量化地下水中CO2和N2 O的损失及其对土壤CO2和N2 O总损失的贡献。
Greenhouse gases dissolved in the soil water and transported through subsurface flow were poorly understood in comparison to their emissions at the soil-atmosphere interface. In this study, leachate CO2and N2O concentrations were monitored on a tea garden (TG) hillslope (cultivated) and a bamboo forest (BF) hillslope (naturally vegetated) from September 2019 to February 2022 in the south-eastern hilly area of China. Leachate CO2and N2O concentrations ranged from 1.07 to 9.83 mg C L−1and from 0.32 to 11.74 μg N L−1, respectively, on the TG hillslope, while they ranged from 0.64 to 25.95 mg C L−1and from 0.23 to 5.68 μg N L−1, respectively, on the BF hillslope. On both hillslopes, leachate CO2concentrations were the greatest in summer, while they were the lowest in winter. On the TG hillslope, the highest and the lowest leachate N2O concentrations were observed in spring and summer, respectively, while on the BF hillslope, they were observed in autumn and winter, respectively. On both hillslopes, soil temperature, precipitation during the previous 15 days, and matrix potential were positively related to the leachate CO2concentrations but not related to the leachate N2O concentrations. Soil water content was positively related to both leachate CO2and N2O concentrations, while such relationships with groundwater table depth were negative. Leachate total inorganic nitrogen and soil total inorganic nitrogen concentrations were positively related to the leachate N2O concentration on the TG hillslope, while such relationships were not observed on the BF hillslope. Spatial variations of leachate CO2and N2O concentrations were mainly influenced by land covers, terrain attributes (slope, elevation), soil particle size distribution, bulk density and soil organic matter content. The findings of this study supplemented the knowledge of soil water dissolved CO2and N2O in the cultivated and naturally vegetated land covers. Further researches are needed to quantify the CO2and N2O losses through subsurface flow and their contributions to the total soil CO2and N2O losses.