碳氮同位素结合稳定同位素模型解析沉积土壤碳源

[目的]研究辽西褐土丘陵区典型小流域不同土地利用方式下经侵蚀沉积过程沉积土壤碳来源,为合理调控小流域土壤侵蚀造成的土壤碳流失提供科学参考.[方法]通过对辽西丘陵沟壑区小流域野外取样,研究小流域沉积土壤碳的来源并量化其贡献.通过GIS结合GPS技术对小流域4种不同土地利用类型(耕地、林地、草地、沟渠)表层土壤及小流域拦沙...

Contribution of Carbon Sources in Sedimentary Soils Combining Carbon and Nitrogen Isotope with Stable Isotope Model

【Objective】To study the sources of deposited soil organic carbon (SOC) under different land use patterns in a typical small watershed in the brown soil hilly area of western Liaoning through eroded sedimentation, and to provide a scientific reference for the reasonable control of soil carbon loss caused by soil erosion in the small watershed. 【Method】Through field sampling of small watersheds in the hilly and gully area of western Liaoning, the sources of deposited soil carbon in the small watersheds were studied and their contribution was quantified. Using GIS and GPS technology to analyze the surface soil of 4 different land use types (cropland, forest, grassland, gully) in the small watershed and 3 locations of the check dam in the small watershed (S1 in front of the dam, S2 in the middle of the dam, S3 behind the dam) 0-100 cm soil profile was sampled to analyze the carbon source of the sedimentary soil based on a mixed carbon and nitrogen isotope model.【Result】Using¹³C and¹⁵N isotopic characteristics and their elemental composition qualitative and quantitative identification of soil organic carbon in eroded sediments in the hilly and gully area of western Liaoning was carried out. The SOC loss was primarily from cropland, accounting for 58.75%, followed by gully (25.49%), forest (9.2%), and grassland (6.49%). 【Conclusion】 The stable isotope SIAR mixing model, as a reliable fingerprint tool, could be successfully employed to estimate the contribution of various C sources within a complex ecosystem, The research results can provide theoretical references for soil protection and nutrient loss control in small watersheds affected by water erosion, and for maintaining the sustainability of the ecosystem.