Equipment Needed: Two clear plastic jars at least 32oz; two 1/4” mesh wire screens cut to fit onto top of jars; dried soil peds
- Encourage participants to complete a Soil Aggregate Slake Demonstration at their own farm, ranch, garden, etc. Comparisons can be completed between cropland fields with cover crops versus cropland fields without cover crops; fields which are no-tilled versus fields which are not no-tilled; soils taken from the fence line versus cropland soils; season long grazing pastures versus rotational grazing system pastures, etc. Ensure soils are from the same or similar soil type and are not sodic (sodic soils will disperse quickly in water).
- Explain that all the soil peds must be dry before performing the demonstration. They can be placed on a window sill or pickup dash for a few days. Soil peds with moisture inside them will offset the water trying to enter them. Consequently, even degraded soil peds will not slake if they are moist inside. Always a good idea to be sure to do a test run with your soil peds BEFORE demonstrating in front of an audience to ensure the soils perform as you expect them to.
- Explain how the soil functions as an aerobic system and requires oxygen. When the soil peds are placed in water, observations will include oxygen bubbling out of the soil ped and move to the water surface.
- Ask the question: How does the water enter the soil ped? Basically the water is looking for pore spaces to enter.
- Explain that as the water enters the pore spaces in the soil ped, it creates a pressure.
- When the soil aggregates, which make up the soil peds, are held together with an adequate amount of glue (glomalin) which is made from a combination of the plant root exudates and fungi; they can resist the pressure and the soil ped stays in tack. Even a healthy soil may slake a small amount, but the water will remain clear. The small aggregates that do slake still maintain their integrity.
- When the glue is inadequate, the pressure becomes too great and the aggregates start to “slake” off the soil ped and fall to the bottom of the container. The poorly aggregated soil slakes into individual soil particles making the water cloudy. If runoff actually occurs from this field, the water quality would be poor.
- Soil organic matter is important in soil aggregation; it helps to hold the soil together and is the food for soil biology.
- Tilled cropland fields typically have a smaller amount of fungi than no-till cropland fields. Tillage implements tend to reduce the fungi hyphae.
- Be sure to offer HOPE. Explain that by practicing the Soil Health Principles we can rebuild a degraded soil or field with time.
