- Carefully select one in-tact soil aggregate from the available soil.
- Place the soil aggregate on the sieve.
- Fill the beaker with approximately 1.5 inches of water, or so that the soil aggregate will be just immersed in water when lowered into the beaker.
- Lower the sieve into the beaker of water. Observe the soil aggregate for 5 minutes and keep track of the timing of structural loss. Refer to the stability class table below to determine class 1 and 2.
- Once stability class 1 and 2 are determined, raise the sieve + aggregate out of the water for one second, and immerse again for another second.
- Repeat immersion 4 times. Refer to the stability class table below to determine and record stability classes 3 through 6.
Table 1. Stability class table (Source: USDA NRCS Soil Quality Test Kit)
- Aggregates of soils high in organic matter are more stable than are those low in OM. Which soil aggregates fall apart when wetted, and which will maintain their stability?
- Discuss the positive and negative impacts of tillage on soil structure. What is a physical consideration in deciding whether to utilize this practice on agricultural land?
- What are 3 management strategies to support and promote soil aggregation?