Dog Park Use and Soil Health in City Parks

ISEF Category: Earth and Environmental Sciences

Subcategory: Environmental Effects on Ecosystems  ·  Difficulty: Intermediate  ·  Setup: School Lab  ·  Time: 1 to 2 Months

The Hook

A busy dog park can change the ground under your feet faster than you think. More traffic can squeeze soil, push out air pockets, and make life harder for earthworms. That makes this a strong real-world question, because parks need soil that can handle use and still support living things. You can measure both sides of that problem.

What Is It?

This project asks how heavy dog-park use changes soil and the tiny animals living in it. Soil compaction means the ground gets packed tighter, so water, air, and roots move through it less easily. Think of it like stomping on a sponge until it feels stiff instead of springy.

Earthworms are a useful sign of soil health because they need moist, loose soil with enough space to move and feed. If visitors and dogs walk the same paths again and again, the soil may become harder and less friendly to worms. You can compare parks with different use levels, then see whether more use lines up with denser soil and fewer earthworms.

Why This Is a Good Topic

This is a strong science fair topic because you can measure it in the field, compare places, and look for a pattern that matters to real park management. You do not need a fancy lab to start, since soil penetrometers, simple cores, or even standardized probe tests can give useful data, and earthworms can be sampled with careful, approved methods. The project also connects to urban ecology, park design, and how people use green spaces. You can learn sampling, statistics, and how to explain a messy real-world system with data.

Research Questions

• How does dog-park visitor count relate to soil compaction in turf areas near and far from the main entrance?
• What is the effect of park use intensity on earthworm density in compacted versus less compacted soil patches?
• Does the distance from a dog-park trail or fence change soil compaction and earthworm counts?
• To what extent do parks with similar grass cover but different usage levels differ in soil hardness and worm abundance?
• Which site features, such as shade, moisture, or leaf litter, best predict earthworm density after accounting for visitor intensity?
• How does the relationship between usage intensity and soil compaction change after rain compared with dry conditions?

Basic Materials

• Soil compaction probe or penetrometer.
• Handheld GPS or phone map app for marking sampling spots.
• Clipboard, field notebook, and waterproof pen.
• Measuring tape or meter stick.
• Disposable gloves.
• Small trowel or soil corer for standardized sampling.
• Ruler or caliper for simple soil depth checks.
• Sealable bags or labeled containers for soil samples.
• Basic earthworm count tray or shallow white pan.
• Camera or smartphone for site photos.
• Portable moisture meter, optional but helpful.
• Park map or printed aerial image.

Advanced Materials

• Digital soil penetrometer with data logging.
• Soil moisture probe with calibration data.
• Bulk density soil core sampler.
• Sieve set for sorting soil organisms.
• Balance for soil mass measurements.
• Stereomicroscope for worm identification or counting juveniles.
• Dissolved oxygen or soil respiration kit, if available.
• GIS software or georeferenced park layers.
• Access to visitor-count datasets or traffic models.
• Statistical software for generalized additive models.
• Weather station data from a nearby source.
• Formalin-free worm extraction setup, if approved by the lab.

Software & Tools

• R: Fits generalized additive models and compares usage patterns with soil measures.
• QGIS: Maps sampling points, park features, and distance from paths or entrances.
• Google Sheets: Organizes field data and checks for missing values.
• ImageJ: Measures soil photo features, like surface cover or sample scale markers.
• PubMed: Finds peer-reviewed review articles on soil compaction, urban ecology, and earthworm ecology.

Experiment Steps

1. Define your main comparison, such as high-use, medium-use, and low-use park zones, and decide how you will measure use intensity.
2. Choose soil indicators that match your tools, then make a plan for how each site will be sampled the same way.
3. Set up controls for moisture, shade, vegetation cover, and distance from paths so you can separate use effects from site effects.
4. Build a data sheet before you go out, so each location records the same field notes, counts, and measurements.
5. Plan your analysis ahead of time, including how you will test for nonlinearity with a generalized additive model.
6. Decide how you will present the results with maps, scatterplots, and confidence bands so the pattern is easy to read.

Common Pitfalls

• Measuring visitor use only once, which misses busy weekends, school days, and weather effects.
• Sampling only the most damaged spots, which makes the park look worse than the average site.
• Counting earthworms after digging different amounts of soil at each site, which breaks comparison between locations.
• Ignoring moisture differences, which can change both soil hardness and worm activity.
• Using visitor data from a source that does not match your park boundaries, which can blur the relationship you are trying to test.

What Makes This Competitive

A stronger project will do more than compare one busy park with one quiet park. It will sample many sites, control for confounders, and test whether the relationship bends instead of staying straight. A good analysis could compare paths, edges, and interior turf, then use a model that handles uneven real-world data. Clear maps, careful field methods, and a thoughtful statistic can move this from simple observation to real ecological evidence.

Project Variations

• Compare dog parks with regular parks that have no off-leash area to see whether use type changes soil and worm patterns.
• Focus on seasonal change by sampling the same parks in wet and dry periods to test whether compaction effects shift over time.
• Swap earthworm counts for other soil macroinvertebrates, such as beetle larvae or ants, if worm sampling is hard at your sites.

Learn More

• USGS soils resources: Search the USGS site for soil structure, compaction, and infiltration background that helps you frame field measurements.
• USDA NRCS Soil Health: Look for free guides on soil physical properties, compaction, and field indicators of soil condition.
• NOAA Climate Data Online: Find local weather and rainfall records to compare with your park sampling dates.
• PubMed: Search review articles on urban soil compaction, earthworms, and recreational disturbance in parks.
• QGIS Documentation: Use the free official docs to map sampling points and park features.