Forms of soil organic nitrogen in a Pactola soil as seen by pyrolysis/gas chromatography/atomic emission detection (Py–GC/AED)

Molecular and Spectroscopic Characterization of Water Extractable Organic Matter from Thermally Altered Soils Reveal Insight into Disinfection Byproduct Precursors

“…While soil heating and solid characterization have been valuable for understanding C and N character and sequestration in soils, − the characteristics, including molecular size and composition, of water extractable organic matter (WEOM) from thermally altered soils has not been well characterized. Wildfires are a modern source of natural soil heating that has received attention lately due to an increase in their frequency and duration in recent decades that is expected to continue. − This increase can be attributed to climate change, extreme droughts, land disturbances, and increased fuel loads. ,− Wildfires are known to severely impact the ecology of forests and grasslands by altering C and N cycling, , macroinvertebrate populations, and vegetation cover. , There are also concerns about how wildfires may alter water quality in streams and reservoirs that provide water for potable water systems. , Following wildfires, alterations to water quality include increased nutrient concentrations, sediment loads, and metals concentrations, which may have negative impacts on drinking water treatment processes. − However, the exact water quality changes depend on many variables including topography, hydrology, weather events, and wildfire specific characteristics, such as temperature and duration, which may be confounding …”

Analytical pyrolysis as a tool to probe soil organic matter

“…In a study dedicated to organic nitrogen, five particle-size fractions were separated from soil samples collected at 3 different depths. Py-GC-AED performed at 3 temperatures (300, 400 and 500 °C) revealed trends with particle-size and depth for ammonia, acetonitrile, hydrogen cyanide, pyridine and pyrrole [77]. Particle-size fractions were also separated from tropical earthworm casts and surrounding soil [117].…”

“…These studies confirmed the secondary reactions which occur upon pyrolysis and highlighted the difficulties in detecting non heterocyclic N in soils. Another a priori promising approach to detect N-containing pyrolysis products is the use of a specific detector such as atomic emission detection (AED) could be identified in a forest soil [77].…”