Organic matter, carbon content, and color variables of soils of 17 green spaces on the Fairfax campus at George Mason University

Healthy soil is needed in order to have food security and carbon storage. Due to the current climate crisis, food security and soil health are important issues that should be addressed. Healthy soil is measured through the amount of organic matter and organic carbon content that is present in it. 17 different locations were chosen across the George Mason Fairfax campus based on the level of human impact and the amount of maintenance put into each space. Soil cores at two different depths (0-15cm and 15-30cm) were taken for soil organic matter (SOM) and Carbon-Hydrogen-Nitrogen (CHN) content analysis. With the use of an inexpensive device called the NIX Pro Color Sensor, the soil color was recorded at the 17 different sites at George Mason University, Fairfax campus. Using the loss of ignition (LOI), the SOM was measured and recorded. Through the use of CHN Analyzer, the amount of organic carbon was determined and recorded. The overall results showed there to be a distinct positive relationship between SOM and carbon content in all green spaces. The areas that are either less disturbed or highly managed showed the highest content of SOM and carbon, indicating that landscape management may have a significant influence on soils’carbon storage potential although it is still preliminary. Further data analysis is warranted, including the examination of the relationships between SOM and the NIX soil color variables. Site-specific limitations and short periods of testing are some of the limitations that this study faced.

Hello everyone this is our presentation on soil organic matter and carbon contact on the GMU Fairfax campus and us 3 had help from Dr. Ahn and Stephanie Schmidt.
These are all the locations that we sampled from in the summer and as you can see there is a lot of variation in the location itself and our original hypothesis believed that the higher coverage in the canopy and shrubby, the higher the SOM content would be in the soil.
So the darkest points on the map represent the highest canopy cover and the lightest green represent the lowest canopy and shrubby cover.
And so here are the pictures of the physical locations.
As you can see again there is a lot of variation in each location. For example, at the top center, the RAC location is a lot more coverage and less foot traffic than the Lecture Hall location. There is obviously maintenance with mowing and a lot of people use that too and get to the classes and move from Blue Ridge to the main part of campus.
So for the methods of this study, we basically collected soil cores from those 17 locations in two different depths from 0 to 15 and 15 to 30 cm and we weighed those samples when they were wet and also when they were dried and then we use the furnace at 550 ° C and about 5 g of the soil to find out how much organic matter content was in each of those soil cores and all the samples about 8 mg were weighed and put in the C H N analyzer in order to find out how much carbon-hydrogen and nitrogen was in each soil core.
We came up with this chart which basically talks about how Potomac Heights garden innovation food forest and wetland mesocosm compound has the highest SOM percentage and carbon content while on the other hand the parking lot L parking lot K and aquatic fitness center and lecture hall had the lowest SOM percentage and carbon and the graph on the left shows that SOM and Carbon are positively correlated with 7 8 % which is the R squared and on the right, we have a SOM and carbon in each of them in each different location and plot and here we have the Carbon and SOM average from 0 to 15 and 15 to 30 cm from the highest which is on the left PHG stands for Potomac Heights garden and all the way to PLK which is parking lot K which is the lowest SOM and carbon.
This is just a map of the 17 locations with the darkest color brown being the locations that have the highest soil organic matter the lightest brown locations being the ones that had the lowest soil organic matter.
As you can see the West campus areas like the wetland mesocosm compound were the ones that had the higher soil organic matter with the main locations that were in the center of campus.
Really having the least soil organic matter which shows foot traffic and human presence in these areas and it does have an effect on the amount of nutrients present.
This is a table of all the color sensor variables we did take color readings of the soil when we took the cores in the field. Right now we’re still working on the data analysis and relationship between them so we don’t have anything definitive currently.
So like I just said we don’t have any clear relationship between those color variables and it is still in process but we do have a clear positive trend between soil organic matter and carbon present in the soil. Soil organic matter really is highest in undisturbed locations like a wetland mesocosm compound.
For the highly maintained areas like the garden in the center of campus and Soil organic matter really is lowest in spaces that are highly disturbed due to mowing or foot traffic like the lecture hall location which really means that George Mason has a lot of room for improvement of its ecosystem for carbon storage to offset its emissions. We thank you so much for taking the time to watch our presentations and look forward to hearing any questions.