Soil gas

Soil gases (soil atmosphere[1]) are the gases found in the air space between soil components. The spaces between the solid soil particles, if they do not contain water, are filled with air. The primary soil gases are nitrogen, carbon dioxide and oxygen.[2] Oxygen is critical because it allows for respiration of both plant roots and soil organisms. Other natural soil gases include nitric oxide, nitrous oxide, methane, and ammonia.[3] Some environmental contaminants below ground produce gas which diffuses through the soil such as from landfill wastes, mining activities, and contamination by petroleum hydrocarbons which produce volatile organic compounds.[4]

Gases fill soil pores in the soil structure as water drains or is removed from a soil pore by evaporation or root absorption. The network of pores within the soil aerates, or ventilates, the soil. This aeration network becomes blocked when water enters soil pores. Not only are both soil air and soil water very dynamic parts of soil, but both are often inversely related.

  1. ^ "Soil air" (PDF). Retrieved 16 October 2022.
  2. ^ Pierzynski, Gary M.; Sims, J. Thomas; Vance, George F., eds. (2005). Soils and environmental quality (3rd ed.). Boca Raton, Florida: CRC Press. Retrieved 16 October 2022.
  3. ^ Kim, Dong Gill; Vargas, Rodrigo; Bond-Lamberty, Ben; Turetsky, Merritt R. (2012). "Effects of soil rewetting and thawing on soil gas flaxes: a review of current literature and suggestions for future research" (PDF). Biogeosciences. 9 (7): 2459–2483. Bibcode:2012BGeo....9.2459K. doi:10.5194/bg-9-2459-2012. Retrieved 16 October 2022.
  4. ^ Marrin, Donn L.; Kerfoot, Henry B. (1988). "Soil-gas surveying techniques: a new way to detect volatile organic contaminants in the subsurface". Environmental Science & Technology. 22 (7): 740–745. doi:10.1021/es00172a001. PMID 22195653. Retrieved 23 October 2022.