河北平原土壤有机碳储量及固碳机制研究

Research on organic carbon storage and sequestration mechanism of soils in the Hebei Plain

利用2005年多目标区域土壤地球化学调查及20世纪70年代末全省第二次土壤普查土壤有机碳数据,对河北平原土壤有机碳密度及碳储量的时空变化规律、固碳机制及固碳潜力等问题进行了研究。结果表明,全省第二次土壤普查时土壤有机碳储量124.86Mt,2005年为176.08Mt,26年中增加了41.02%,表现出"碳汇"效应。据不同土类有机碳含量最大值估算,河北平原尚有188.6Mt的固碳潜力。稳定的Corg/N比、较高的N、P、Se含量等土壤理化环境条件以及农业施肥、秸杆还田、浅耕、免耕等农业管理措施促进了土壤有机碳的积累;而干旱碱性富钙、盐渍化、高硅钾的沙性土壤环境以及人为对自然湿地的扰动则会使有机碳丢失。

Based on soil organic carbon data obtained by multi-purpose regional geochemical survey in 2005 and the Second Soil Survey over the whole province in 1970s, this paper studies the issues such as temporal and spatial variation of soil organic carbon density and soil organic carbon reserves, mechanism of soil carbon sequestration, and soil carbon sequestration potentials in the Hebei Plain. The results showed that the soil organic carbon density in the plain was 2.21 kg/m^2 , which was significantly lower than that nationwide. The soil organic carbon storage was 124. 86 Mt in the period of the Second Soil Survey in 1979, and 176.08 Mt in 2005, which increased by 41.02% over the 26 years, showing the effect of a ＂carbon sink＂. The soil carbon sequestration potential was 188. 6Mt according to the maximum value of organic carbon content of different types of soils. The factors including the soil physical and chemical properties, such as the stable soil organic carbon-nitrogen ratio, the high soil nitrogen, phosphorus, selenium content etc. , and agricultural management measures, such as the agricultural fertilizer application, the straw-returning, shallow tillage, no-tillage etc. , promoted the accumulation of soil organic carbon. On the opposite side, factors such as droughty climate, abundant calcium, alkali-saline, high silicon and kalium sandy soils and the natural wetland environment dis turbed by people, induced the loss of soil organic carbon.