喀斯特石漠化治理区土壤CH4和CO2排放研究

本研究采用静态密闭箱-气相色谱法,于2016年12月到2017年11月对重庆市南川石漠化治理示范区4个岩溶碳汇试验区(金银花地JYH、人工造林地杨树林YSL、坡改梯PGT、经济作物花椒林地HJ)及3个对照区(荒地HD、非坡改梯FPGT、弃耕地QGD)的土壤甲烷、二氧化碳的浓度及排放通量进行原位观测,探讨我国南方喀斯特石漠化地区甲烷和二氧化碳浓度分布和时空排放规律,及岩溶区土壤温度、土壤含水率等环境因子对甲烷、二氧化碳排放的影响。结果表明:不同植被类型下土壤CO_2的浓度范围为5 003. 64～19 163. 23 mg/m~3,土壤CH_4的浓度范围为5. 35～7. 46 mg/m~3。土壤CO_2的排放通量具有随季节变化土壤CO_2排放通量随季节明显变化,在一定范围内土壤温度及土壤含水率都与CO_2排放通量呈显著正相关关系。土壤CH_4释放速率没有明显的季节变化规律,在个别月份出现显著变化表现为巨大的源与汇,主要是受到土壤温度、土壤含水率及土壤微生物的共同影响。

Study on Soil CH4 and CO2 Emissions from Karst Rocky Desertification Control Area

In this study, the soil methane and carbon dioxide concentration and release flux in 4 karst carbon sink test areas (YH, YSL, PGT, HJ) and 3 controlled areas (HD, FPGT, QGD) were observed from December 2016 to November 2017 in the demonstration area of Chongqing Nanchuan desertification control. The distribution of methane and carbon dioxide in the rocky desertification area of Karst in southern China and its temporal and spatial emission rules, and the effects of environmental factors such as soil temperature and soil water content on methane and carbon dioxide emissions in karst areas are discussed. The results showed that under different vegetation types the soil CO₂ concentration range was 5 003.64~19 163.23 mg/m³, and the soil CH₄ concentration range was 5.35~7.46 mg/m³. Soil CO₂ emission fluxes changed significantly with seasons. In a certain range, soil temperature and soil moisture content were positively correlated with CO₂ emission fluxes. There was no obvious seasonal variation in soil CH₄ release rate, and significant changes in individual months showed a huge source and sink, mainly affected by soil temperature, moisture content and soil microorganisms.