野外可攜式風洞
要點：
1. 評估了初級土壤組分（即砂粒、粉粒和黏粒）與二級土壤組分（團聚體）對風蝕的敏感性。
2. 確認了兩個粒度值53μm與300μm可作為團聚體分級的臨界值。
3. 微團聚體組分和大團聚體組分與侵蝕速率成反比關係。
4. 檢測到粒度範圍75-150μm是最易侵蝕的土壤組分。
5. 粉粒與黏粒在微團聚體和大團聚體組分中佔優勢，而在中等團聚體中則以砂粒為主。
摘要：土壤粒度分布（PSD）在風蝕研究和泥沙輸移模擬中發揮著重要作用。現有研究很少關注在自然條件下不同土壤組分對風蝕的敏感性問題。本研究旨在使用可攜式風洞裝置測量乾旱半乾旱地區60個非擾動土壤的原位風蝕速率。初級（即黏粒、粉粒和砂粒）和16種二級（團聚體）土壤顆粒粒度等級的作用於風蝕速率有關。此外，土壤主要組分（即微團聚體，中等團聚體和大團聚體）之間臨界值得以確定。研究結果表明，黏粒與粉粒組分及表層的巖石碎屑組分與風蝕速率成反比，呈冪函數關係；而砂粒組分呈正比例的指數關係。微團聚體、中等團聚體和大團聚體的粒度範圍分別為<53μm、53-300μm和>300μm。風蝕速率與中等團聚體組分呈正比關係，而與微團聚體組分和大團聚體組分呈反比關係。此外，75-150μm這一較窄土壤粒度範圍的組分被檢測為最易侵蝕的土壤組分。初級土壤顆粒在主要的團聚體組分中的分布存在差異，因而在中等團聚體中，砂粒佔優勢；在微團聚體和大團聚體中，粉粒，尤其是黏粒佔優勢。研究結論：與細小的初級顆粒（黏粒）相關的土壤大團聚體（>300μm）的存在可以顯著降低風蝕速率，而不是含有較少團聚體的沙質土壤。
關鍵詞：團聚體分級；可蝕性組分；粒度分布；風洞
圖11. 16個粒度區間團聚體的質量百分比與初級顆粒組分（即黏粒、粉粒和砂粒）之間的相關性
原文網址：
https://www.sciencedirect.com/science/article/pii/S0016706119305671
https://doi.org/10.1016/j.geoderma.2019.113936
Thefractionation of soil aggregates associated with primary particles influencingwind erosion rates in arid to semiarid environments
Highlights:
1. Thesusceptibility of primary and secondary soil fractions to wind erosion wasassessed.
2. The boundariesof 53μm and 300μm were recognized for aggregates fractionation.
3. Erosion rate wasinversely proportional to micro- and macro-aggregate fractions.
4. The size rangeof 75–150μm was detected as the most erodible soil fraction.
5. Silt and clayprevailed in micro and macro fractions, whereas sand in meso-aggregates.
Abstract:Soil particle size distribution (PSD) plays an important role in wind erosionstudies and sediment transport modeling. Few studies have been done focusing onthe susceptibility of different soil fractions to wind erosion under naturalconditions. This study was performed to measure in-situ wind erosion ratesusing a portable wind tunnel facility on 60 undisturbed soils of arid tosemiarid regions. The effects of primary (i.e. clay, silt, and sand particles)and 16 secondary (aggregate) size classes were attributed to wind erosionrates. Moreover, the boundaries between major fractions of the soils (i.e.micro-aggregates, meso-aggregates and macro-aggregates) were determined. Theresult showed that clay and silt particles and also surface rock fragment wereinversely proportional to wind erosion rates as power functions, whereas sandcontent showed a positive exponential relationship. The size ranges of<53μm, 53–300μm and >300μm were distinguished for themicro-aggregates, meso-aggregates, and macro-aggregates, respectively. Themeso-aggregate fraction was proportional and the micro-aggregate andmacro-aggregate fractions were inversely proportional to wind erosion rates.Furthermore, a narrower size range of 75–150μm was detected as the most erodiblesoil fraction. The distribution of the primary particles in the major aggregatefractions was different, so that in the meso-aggregates, sand particles and inthe micro-aggregates and macro-aggregates, silt and especially clay particlespredominated. It is concluded that the presence of macro-aggregates(>300μm) associated with fine primary particles (clay) can significantlyreduce wind erosion rate rather than the sandy soils containing weakeraggregates.
Keywords:Aggregate fractionation; Erodible fraction; Particle size distribution; Windtunnel
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