Soil Compaction Data Collection

An introduction to my most recent project:

Dan Schwartz, the soil scientist in the Northern Virginia Soil and Water Conservation District, performed a study in the fall of 2020 to study the compaction of soils in lawns in Arlington County. Soil compaction is common in residential areas, and some consequences of soil compaction can be easily seen. For example, it’s not difficult to find cracked foundations near a house or a cracked garage slab. soil compaction occurs when soil particles compress together, reducing water infiltration because compacted soils are less porous. Preventing soil compaction can encourage plant growth and prevent the risk of oxygen deficiency.

Working with the NVSWCD and the Virginia Soil Water Conservation District, I started a project several months ago to study soil compaction under the Youth Conservation Leadership Institute (YCLI). My project proposal was to perform a simplified continuation of Dan’s study in Fairfax County, where I live. The goal of my project is to collect and analyze data on topsoil depth and infiltration rates of lawn soil at Fairfax County Residences of varying ages. Pending funding, I also plan to analyze the bulk density and organic matter content in the soil.

Here is an introduction to some of the soil tests:

First, I will recruit a few volunteers who may want to participate in this project, spread over at least five residences. For each residence, I will call Miss Utility to mark utility lines, and once the marking is done, I will conduct the field sampling. I will collect at least ten samples in total, across at least five residences; for each house, one sample will be taken from the front yard and one sample will be taken from the backyard.

To test the infiltration rate of the soil, I will need to use a double ring infiltrometer to measure how quickly water soaks into the ground. The measurements must be taken in the field I fill the infiltrometer with water from my jug. Again, one measurement will be taken in the front and one will be taken in the backyard. Then, to measure the topsoil depth, I will use a soil push probe to extract small cores of soil throughout the front and backyard. I will take at least 5 cores and select one that seems to best represent conditions in the yard. Then, I’ll measure the topsoil depth in the representative core with tape measure to nearest 1/4″.

Lastly, to test bulk density, an indicator of soil compaction, and the amount of organic matter in the soil, I will need to use a slide hammer to extract a soil core of a known volume encased in a metal ring. Pending funding, I will then send the sample off to a soil laboratory (WayPoint Analytical, Richmond, VA) to be oven dried and then tested for bulk density and soil organic matter percentage (by weight). My results will be added to an existing data set to determine if soil qualities change in relation to the age of residence.

Here are some photos from the two houses I’ve been working on so far:

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