Preferential flow of gas in soils

气体在土壤中优先流动

基本信息

批准号：
251408-2008
负责人：
Allaire, Suzanne
金额：
$ 1.38万
依托单位：
Université Laval
依托单位国家：
加拿大
项目类别：
Discovery Grants Program - Individual
财政年份：
2012
资助国家：
加拿大
起止时间：
2012-01-01 至 2013-12-31
项目状态：
已结题

来源：
https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=497011
关键词：
Preferential flow gas soils

项目摘要

Gas move in soils because soils are porous media with connected pores. This gas movement allows billions of organisms such as plants, bacteria, and fungus to breathe and decompose products (e.g. hydrocarbons). These activities generate gases that must be eliminated from the soil toward the atmosphere to avoid toxicity. Gases, as for water, do not homogeneously move in soils. Gases use pathways through only a portion of the soil, called 'preferential flow pathways', which favour faster movement of gases than it would be predicted with models if the gases would be moving through the bulk soil volume. Preferential flow is caused by soil heterogeneities of all sizes. PF affects the growth of plants and micro-organisms, chemical-reactions, efficiency of soil decontamination systems and gas capturing systems in landfills, etc. Very little is known on PF of gases in soils. The main objective of this research is to understand and quantify PF of gas in soils under several conditions (e.g. frozen, wet, with macropores). Laboratory experiments will be conducted on repacked soil columns and on large monoliths in which soil heterogeneity is as observed in the field. The monoliths will be scanned (CT scanner as in hospitals) to describe soil porosity in three dimensions and correlate the porosity structure with PF of gas. This project is an important step in improving knowledge on gas flux in soil. It will help in developing more appropriate models, soil management and decontamination, improving data interpretation relative to plant, microbes, oxydo-reduction reactions, and efficiency of engineering processes in soils.

气体在土壤中移动，因为土壤是带有连接孔的多孔培养基。这种气体运动允许数十亿种植物，细菌和真菌等生物呼吸和分解产物（例如碳氢化合物）。这些活动产生的气体必须从土壤向大气中消除，以避免毒性。对于水，气体不会同质在土壤中移动。气体仅通过一部分土壤（称为“优先流动途径”）使用途径，如果气体将通过大块土壤体积移动，则比使用模型预测的气体更快。优先流是由各种大小的土壤异质性引起的。 PF会影响植物和微生物的生长，化学反应，土壤去污染系统的效率以及垃圾填埋场中的气体捕获系统等。这项研究的主要目的是在几种条件下（例如冷冻，湿，大孔）理解和量化土壤中气体的PF。实验室实验将在重新包装的土壤柱和大量的大块上进行，其中土壤异质性如在现场所观察到的。将扫描整体（在医院中，CT扫描仪），以描述三个维度的土壤孔隙率，并将孔隙率结构与PF相关。该项目是改善土壤中气通量知识的重要一步。它将有助于开发更合适的模型，土壤管理和净化，改善相对于植物，微生物，减少食物减少反应以及土壤中工程过程的效率的数据解释。