Inorganic Geochemistry, Centre for Environmental Geochemistry, British Geological Survey, Nottingham, NG12 5GG, UK.
School of Geography, Earth and Environmental Sciences, University of Plymouth, Plymouth, Devon, PL4 8AA, UK.
Environ Geochem Health. 2024 Jul 29;46(9):338. doi: 10.1007/s10653-024-02084-2.
Climate change poses an immediate threat to tropical soils with changes in rainfall patterns resulting in accelerated land degradation processes. To ensure the future sustainability of arable land, it is essential to improve our understanding of the factors that influence soil erosion processes. This work aimed to evaluate patterns of soil erosion using the activity of plutonium isotopes (Pu) at sites with different land use and clearance scale in the Winam Gulf catchment of Lake Victoria in Kenya. Erosion rates were modelled at potential erosive sites using the MODERN model to understand small-scale erosion processes and the effect of different management practices. The lowest soil redistribution rates for arable land were 0.10 Mg ha yr showing overall deposition, resulting from community-led bottom-up mitigation practices. In contrast erosion rates of 8.93 Mg ha yr were found in areas where steep terraces have been formed. This demonstrates the significance of community-led participation in effectively managing land degradation processes. Another key factor identified in the acceleration of soil erosion rates was the clearance of land with an increased rate of erosion over three years reported (0.45 to 0.82 Mg ha yr) underlining the importance vegetation cover plays in limiting soil erosion processes. This novel application of fallout plutonium as a tracer, highlights its potential to inform the understanding of how soil erosion processes respond to land management, which will better support implementation of effective mitigation strategies.
气候变化对热带土壤构成了直接威胁，降雨模式的变化导致土地退化进程加速。为确保耕地的未来可持续性，必须提高我们对影响土壤侵蚀过程因素的理解。本研究旨在通过在肯尼亚维多利亚湖温亚马湾流域不同土地利用和清理规模的地点使用钚同位素（Pu）的活性来评估土壤侵蚀模式。使用 MODERN 模型在潜在侵蚀点模拟侵蚀速率，以了解小尺度侵蚀过程和不同管理实践的影响。可耕地的最低土壤再分配率为 0.10 Mg ha yr，总体呈沉积状态，这是社区主导的自下而上缓解实践的结果。相比之下，在形成陡峭梯田的地区发现的侵蚀速率为 8.93 Mg ha yr。这表明社区主导的参与在有效管理土地退化过程方面的重要性。另一个加速土壤侵蚀速率的关键因素是土地清理，据报道，三年内的侵蚀速率增加（0.45 至 0.82 Mg ha yr），这突显出植被覆盖在限制土壤侵蚀过程中的重要性。这种沉降钚作为示踪剂的新应用，突出了它在了解土壤侵蚀过程如何响应土地管理方面的潜力，这将更好地支持实施有效的缓解策略。
