Aggregation
What it is: Aggregate stability is a measure of a soil's ability to remain aggregated despite stresses from tillage, raindrop impact, etc.
Why it is important: Surface crusts and filled pores occur in weakly aggregated soils. Surface crusts prevent infiltration and promote erosion; filled pores lower water-holding and air-exchange capacity and increase bulk density, diminishing the conditions for root growth.
Specific problems that might be caused by (too little, too much etc.):
Too little: erosion, high bulk density, poor root development
Too much: ?
What you can do: You can improve the aggregate stability of your soil by increasing levels of organic matter or applying specialized chemical compounds such as anionic polyacrylamide (PAM).
For more information go to Soil Management Practices.
Ways that you can measure soil aggregation include:
| Method | How Performed | Comments |
|---|---|---|
| Mean weight diameter (MWD) | ||
| Aggregate stability | Field or lab test | |
| % macro aggregates | ||
| % micro aggregates | ||
| Slaking | Field or lab test |
The different methods have different levels of accuracy and precision.