Compaction Risk Calculator

Enter Garden Conditions

Example Data Table

Formula Used

The calculator builds a Compaction Risk Score from weighted factors and protective bonuses. Each factor maps to points, then totals are clamped between 0 and 100.

• Texture (0–20): finer soils score higher.
• Moisture (0–27.5): wet soil increases risk quickly.
• Traffic (0–20): scales up to 14 passes/week.
• Load (0–27.5): heavier equipment adds more points.
• Drainage Add (0/5/10): poor drainage extends vulnerability.
• Bonuses (−0 to −20): organics, mulch, and raised beds reduce risk.

How to Use This Calculator

1. Choose soil texture based on your garden’s dominant feel.
2. Pick moisture by squeezing soil into a ball or ribbon.
3. Estimate weekly passes for your busiest work period.
4. Select the typical load that contacts the soil surface.
5. Enter organic matter from a test, or your best estimate.
6. Set drainage based on ponding time after rainfall.
7. Click Calculate Risk to view score and actions.
8. Use CSV or PDF exports to track changes over seasons.

Root‑Zone Impact of Compaction

Compaction squeezes soil pores, reducing air and water movement. Roots meet mechanical resistance, branch less, and absorb fewer nutrients. Symptoms include stunted growth, puddling after irrigation, and uneven germination.

Collapsed pores slow microbes and can concentrate salts near the surface. A crust can block seedlings after heavy rain. Protecting structure preserves yield and water efficiency.

Moisture and Texture Drive Vulnerability

This calculator weights texture and moisture because fine particles pack tightly. Clay and silt score higher than loam and sand. Wet conditions raise risk sharply because pore water lubricates particles and allows rapid rearrangement under pressure.

Texture adds up to 20 points and moisture up to 25. If unsure, choose the wetter option; working damp soil can cause longer damage than waiting a day.

Traffic Frequency and Load Intensity

Repeated passes matter as much as heavy equipment. Traffic points rise to 14 passes per week, then saturate. Load scales from foot traffic to tractors and heavy machines, reflecting pressure and rutting.

Load adds up to 25 points, so one tractor pass on wet clay can rival many foot passes on dry sand. Permanent walkways and boards cut passes while keeping workflow smooth.

Structure Protection Through Organic Inputs

Organic matter improves aggregation and elasticity, helping soil rebound after stress. The score subtracts an organic bonus up to 10 points when organic matter approaches 10%. Mulch and raised beds add further protection by buffering impact and improving drainage.

Compost, leaf mold, and cover crops create stable aggregates and bio‑pores. Add organics steadily and keep beds covered to limit surface sealing.

Using Results for Practical Planning

Interpret 0–29 as low risk, 30–49 as moderate, 50–69 as high, and 70+ as very high. When risk is high, shift tasks to drier windows, route movement onto permanent paths, and spread loads with boards.

After changes, export records and compare scores across weeks. If risk stays high, consider raised beds, drainage improvements, or a recovery cycle using broadforking and deep‑rooted cover crops.

FAQs

1) What does the risk score represent?

It is a 0–100 estimate of how likely your current conditions will compact the root zone. It combines texture, moisture, traffic, load, drainage, and protective practices into one comparable number.

2) How can I estimate organic matter if I lack a test?

Use a soil report if possible. Otherwise, use typical ranges: new beds often 2–4%, well‑amended gardens 5–8%, and heavily composted beds 8–10%+. Update the value when you get lab results.

3) Why is wet soil more vulnerable?

Water fills pores and reduces friction between particles. Under pressure, particles slide and pack tightly, collapsing air space. That damage can persist for weeks, especially in fine‑textured soils.

4) Do raised beds always reduce compaction risk?

Raised beds often drain faster and keep traffic off the growing zone, which lowers risk. They still compact if you step in them or work them wet, so maintain paths and avoid wet‑season pressure.

5) What are quick recovery steps for compacted beds?

Stop traffic, add organic amendments, and use gentle loosening such as broadforking rather than deep tillage. Deep‑rooted cover crops and mulching help rebuild pores over time.

6) How often should I recalculate?

Recheck when moisture, equipment, or traffic changes, and after heavy rain. Many gardeners track weekly during busy seasons, then monthly once beds are protected and stable.