Location: Northern Great Plains Research Laboratory
Project Number: 3064-21600-001-006-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Jul 1, 2022
End Date: Jun 30, 2025
Objective:
The objective of this work is to understand how plant secondary metabolites such as small phenolic compounds are contributing to CO2 efflux from soils. This work will lead to a better understanding of how management practices could be altered to lessen the impact of abiotic CO2 from farm lands. We hypothesize that small phenolic compounds such as hydroxy-benzoic and cinnamic acids, common in crops, are contributing to the redox cycling of metals such as Fe and Mn in soils, causing a release of carbon as CO2 from metal oxides.
Approach:
Test soils will be selected and oven dried to limit microbial activity. These soils will represent a wide range a soil types, that have different Mn and Fe content. Test phenolic compounds, related to gallic acid, will vary slightly in chemistry, and will initially include benzoic acid, pyrogallol, and syringic acid. CO2 efflux will initially be measured using a microplate-based respiration system or by static incubations. These systems allow for a fast and reliable determination of the CO2 production. Often used for experiments to determine microbial usage of a substrate, here they will be used as a screening tool to test multiple soils and phenolics. Based on these initial screens, follow up experiments will be performed on a larger scale. With the selected soils, metal chelating agents will be added to determine the effect that metals are having on the release of CO2. In addition to measuring CO2 changes in soil redox potential will be measured using a benchtop pH meter with an ORP/redox probe.
