What Are Soil Aggregates?

Soil aggregates are oil particles that bind together into clumps.  When they bind together, pore spaces increase and because without proper pore space air and water penetration is greatly reduced.

What is Aggregate Stability?

Aggregate stability refers to the ability of soil aggregates to resist dispersion when outside forces (usually associated with water) are applied.


Does SoilTech cause individual clay soil particles to aggregate and remain stable against flowing water?


This test determins whether the addition of SoilTech to clay soil will cause or improve soi particle aggregation.  Soil scientists agree that a soil with good aggregate stability improves soil aeration, water percolation, and infiltration over time.  Increased stable soil aggregates will also reduce bulk density and aid in the soil water-holding capacity over time as well.  Also, formation and preservation of aggregates will allow organic matter to be preserved in the soil.

Materials and Methods:

The effect of SoilTech on the ability to aggregate clay soil particles was determined by the following procedures. Four batches of 120 grams of Chandler clay soil were pulverized to pass through a 0.25mm sieve and 30mL of water was added with varying amounts of SoilTech (0%, 2%, 5%, and 10%) added to different batches.  The soil was well mixed and pressed through a 4mm sieve.  After drying for 2 days in a warm room at low humidity, air at 50°C was blown on the soil for 10mins to complete the drying.  40gm samples were placed on the top sieve of a set of three, 0.84mm, 0.42mm, and 0.25mm arranged in decreasing size.  The sieves were raised and lowered in distilled water through a distance of 1.5cm at the rate of 30 cycles per minute for three minutes.  At the end of that time the sieves were raised, allowed to drain, the soil was then dried at 80°C, and weighed.  This procedure was repeated two times.  This process was replicated three times, producing three samples for each level of SoilTech added.  The results are reported as the percent of soil aggregates larger than 0.25mm.

Test Results:

The Percent of Soil Aggregates Larger Than 0.25mm in Chandler Clay Soils

 % SoilTech Used% Aggregates Larger Than 0.25mmAverage
Sample   #1Sample   #2Sample   #3
Batch   #10%0%0%0%0%
Batch   #21%19%16%22%19%
Batch   #32%67%58%64%63%
Batch   #45%88%77%70%78%
Batch   #510%91%93%74%86%


The largest % increase occurs between 1% and 2%. Application rates beyond 2% improve the aggregate structure of the soil, but could become a cost factor.  The test supports the product claim that SoilTech not only improves the structure of clay soil by increasing aggregate size, but also shows that those aggregates are stable.