南方典型红壤区不同水保措施下坡面产流产沙及稀土迁移特征

以南方典型红壤区福建省长汀县水土保持科教园5种水土保持措施为研究对象,采集坡面产流产沙及稀土迁移数据,以期揭示南方红壤区水保措施的减水减沙效益及对稀土迁移的阻控效应。结果表明:(1)全坡面种草、封禁、低效马尾松施肥、乔灌草混交、人工补植马尾松5种水土保持措施的年均减流率和年均减沙率分别为65.41%,69.29%,63.42%,86.19%,72.59%和91.87%,84.21%,81.54%,94.13%,81.75%。(2)各降雨量下,5种水土保持措施径流和泥沙的稀土迁移强度分别比对照小区低85.13%,94.86%,66.89%,95.46%,93.10%和89.92%,80.38%,70.18%,93.38%,92.73%;且中雨时,各水保措施下径流和泥沙的稀土迁移强度最高。(3)除全坡面种草措施外,其余4种水土保持措施下径流的轻稀土迁移强度比重稀土迁移强度低55.68%,40.38%,85.76%,85.94%;而5种水土保持措施下泥沙的重稀土迁移强度则比轻稀土迁移强度低82.29%,81.25%,78.38%,75.35%,77.05%。综上,5种水土保持措施均有较好的减水减沙效益和稀土阻控效应,其中乔灌草混交措施的效果最佳。研究结果为充分发挥水保措施在生态修复和稀土迁移中的作用提供科学依据和实证支撑。

Characteristics of Slope Runoff and Sediment Yield and REEs Migration Under Different Soil and Water Conservation Measures in a Typical Red Soil Region of Southern China

Five kinds of soil and water conservation measures in a typical red soil region in Changting County of Fujian Province were studied, the data of slope runoff, sediment yield and rare earth elements(REEs) migration were collected to reveal the benefits soil and water conservation measures on runoff and sediment reduction and rare earth migration resistance . The results showed that: (1) The average annual runoff reduction rates and the average annual sediment reduction rates of five kinds of soil and water conservation measures (the whole slope coverd by grass, closed forest, low-effect masson pine fertilization, mixture of trees with shrubs and herb, enrichment planting masson pine) were 65.41%, 69.29%, 63.42%, 86.19%, 72.59% and 91.87%, 84.21%, 81.54%, 94.13%, and 81.75%, respectively. (2) Under the rainfall, the REEs migration intensity of runoff and sediment were 85.13%, 94.86%, 66.89%, 95.46%, 93.10% and 89.92%, 80.38%, 70.18%, 93.38%, and 92.73% lower than those in control plot under five kinds of soil and water conservation measures, respectively, of which, the peak occurred in in moderate rain. (3) The LREE migration intensity of runoff were 55.68%, 40.38%, 85.76% and 85.94% lower than HREE migration intensity under five kinds of soil and water conservation measures except the whole slope covered by grass, and the HREE migration intensity of sediment were 82.29%, 81.25%, 78.38%, 75.35% and 77.05% lower than LREE migration intensity under 5 five kinds of soil and water conservation measures. In summary, five kinds of soil and water conservation measures have markedly benefits of runoff and sediment reduction and REE resistance, especially for of the mixture of trees with shrubs and herb. The results provide scientific basis and empirical support for making the best use the role of soil and water conservation measures applying in ecological restoration and rare earth migrations.