State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F University, Yangling, Shannxi Province, 712100, PR China; Institute of Soil and Water Conservation, CAS and MWR, Yangling, Shaanxi Province, 712100, PR China.
State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F University, Yangling, Shannxi Province, 712100, PR China; Institute of Soil and Water Conservation, CAS and MWR, Yangling, Shaanxi Province, 712100, PR China.
Sci Total Environ. 2018 Jun 1;626:842-850. doi: 10.1016/j.scitotenv.2018.01.156. Epub 2018 Feb 19.
Beryllium-7 (Be), as a potentially powerful tracer, was widely used to document soil redistribution and identify sediment sources in recent decades, but the quantity and distribution of Be in vegetation, soil, sediment and runoff on the Loess Plateau have not been fully described. In this study, we measured Be in vegetation, soil, sediment and runoff on the northern Loess Plateau of China and analyzed its variations during the rainy season to assess the potential of the Be method for documenting soil redistribution and identifying sediment sources in a wide range of environments. The results indicated that vegetation, soil, and sediment samples showed higher levels and larger variations of Be activities during the rainy season. The drying plants showed Be mass activity that was more than three times higher than that of living and semi-decomposed plants. Be mass activity in plants and sediment was much higher than in the soil. Be activity in runoff water with a few submicron suspended particles varied slightly and was far lower than in plant, soil and sediment samples. The cumulative precipitation generally determined Be inventory held by plants and soil. An inverse relationship was found between the Be mass activity in sediment and the sediment amount. Globally, approximate 30% of the total Be was held by plants in both the herbaceous and subshrub plots. Approximate 10% of the total Be was lost with sediment from the bare plot. A very small proportion of Be (1.18%-3.20%) was lost with runoff, and the vast majority of Be was retained in the slope soil at the end of rainy season. Vegetation cover and soil erosion significantly affected the spatial distribution and variations of the Be inventory in soil, providing a necessary condition for the development of a Be method to document soil erosion on slopes with vegetation.
铍-7（Be）作为一种潜在的强大示踪剂，在最近几十年中被广泛用于记录土壤再分布并识别沉积物来源，但黄土高原植被、土壤、沉积物和径流水体中 Be 的数量和分布尚未得到充分描述。本研究测量了中国黄土高原北部植被、土壤、沉积物和径流水体中的 Be，并分析了雨季 Be 的变化，以评估 Be 方法在广泛环境中记录土壤再分布和识别沉积物来源的潜力。结果表明，雨季植被、土壤和沉积物样品的 Be 活度水平较高且变化较大。干燥植物的 Be 质量活度比活体和半分解植物高 3 倍以上。植物和沉积物中的 Be 质量活度远高于土壤。含有少量亚微米悬浮颗粒的径流水体中的 Be 活性变化不大，远低于植物、土壤和沉积物样品中的 Be 活性。累积降水量通常决定了植物和土壤中 Be 的储量。发现沉积物中 Be 质量活度与沉积物量呈反比关系。在草本和亚灌木样地中，全球约有 30%的 Be 总量被植物所固定。裸地的沉积物中约有 10%的 Be 流失。很少一部分 Be（1.18%-3.20%）随径流水流失，绝大部分 Be 在雨季结束时保留在坡面土壤中。植被覆盖和土壤侵蚀显著影响土壤中 Be 储量的空间分布和变化，为利用 Be 方法记录植被坡面土壤侵蚀提供了必要条件。
