Water Infiltration
“It’s not how much rain you get in the rain gauge, it’s how much rain can your soil infiltrate and hold.”
-Gabe Brown
The Importance of benchmarking
Water Infiltration
The speed at which water can infiltrate your soil can tell you so much more than just that. When water penetrates the surface, it fills the pore space created by soil aggregates. Without soil aggregates, water has a difficult time penetrating the soil. Without soil aggregates, soil biology does not have an environment to thrive in. Without a living root, root exudates are not being released into the soil, and soil aggregates will not be formed.
Benchmarking your soil with a water infiltration test is a good idea to gauge the health of your soil. (soil aggregation).
By collecting infiltration data, you can track improvements and start to understand what management practices result in a more resilient soil - one that can infiltrate and hold water.
Water Infiltration Kit.
The Supplies Needed
• 6 inch diameter water infiltration ring. Contact us for one or make your own.
• A water jug. (minimum 4 liters)
• 500 ml water bottle with 5 holes drilled in the cap
• 2" x 4" block of wood (to pound ring into ground)
• Post Maul
• Timing Device (cell phone)
Additional Resource: https://www.canr.msu.edu/news/determining_soil_infiltration_rate
Step 1
Benchmark nature
Find a fence line or native grass area close to the field you are wishing to test. Pound the infiltration ring into the ground 4-5 inches as even as possible. Fill the (500 ml) water bottle to the top and secure the perforated lid.
*Start the timer and begin pouring water into the ring, applying just enough pressure as to stimulate the speed of rainfall hitting the surface.
Land managed by nature will infiltrate 1 inch of water between 10-100 seconds. We measure the first area because it is important to get an idea of potential infiltration when nature is in charge vs. centuries of tillage, synthetic fertilizer & monocultures.
Step 2
Benchmark Your field
Find an area of the field that would best represent the soil type and management practices of the overall field. Try to avoid high/low spots, very sandy/high clay or compaction areas. Pound infiltrator into the ground and use the same process as step 1.
Stop timer once there is no more pooling water visible, and record your results.
Step 3
Replication
Find another spot in the field with the same characteristics, but far away from the original test. Use the same procedures as the first two steps. If results from the two tests vary greatly, it is recommended to do another test. The more tests and readings taken, the greater the accuracy of this procedure.
These results are only a benchmark. Every farm, soil type & management practices will yield different results. Which is why it is important to do this on your own farm. See below for some infiltration tests we have done on the farm.
Canola/Wheat
1st inch = 55 min
2nd inch= 12-16 hrs
Full Season Cover
1st inch = 5 min
2nd inch= 33 min
Corn Silage
1st inch =60 min
2nd inch= >16 hrs
Corn/Vetch
1st inch = 4 min
2nd inch = 22 min
Rye/Vetch
1st inch = 10 min
2nd inch = 48 min
The Protocol
Key Points To Remember
Infiltration tests done on compacted headland
Two inch tests on compacted soils can be very time consuming (up to 20 hours). If time is not issue, it is highly recommended to follow protocol as closely as possible. The results of these tests really drive home the point of how little water our soils can actually infiltrate.
If possible, GPS reference on your phone or flag the location of each infiltration test done so you're able to come back to the same spot next spring.
Learn More
How do I increase water infiltration on the farm?
If you’ve read this far, and have benchmarked soil managed by Mother Nature - the obvious answer to increasing water infiltration is to mimic what she is doing.
Increase plant diversity to simulate diverse soil biology. Learn More
Balance C:N Ratio. Learn More
Keep the soil covered/armored
Minimize disturbance. (mechanical, chemical, fertilizer)
Integrate livestock
Keep a living root in the ground to feed soil biology. Learn More