The soil aggregate is a house for soil life, with macropores and micropores (openings) holding air and water within a mineral (bricks) and SOM (mortar) matrix. Compaction reduces porosity. Macropores (> .08mm) hold water when it rains and let it drain freely afterward. This allows air to return to help oxygenate soil for aerobic processes like decomposition.
Micropores (< .08mm) store water longer-term for crops. There are even ultra-micropores in soils that contain activated carbons!
All About Aggregates
Overall, soil aggregates have huge (but microscopic) surface areas when the edges and planes of various mineral and organic materials are taken into account. These surfaces provide points for adhesion of water molecules and nutrient ions to soil surfaces and cohesion of molecules to each other within porous soil spaces.
Well-aggregated soils have a high cation exchange capacity (CEC). This means they hold and release more nutrients and water than soils with low CEC.
Soil life also thrives within these soils and helps regenerate them by connecting the soil’s water, nutrient and communication pathways as it shreds organic matter for decomposition, excretes micro manure, and fixes nitrogen right out of the atmosphere.
By building below-the-surface habitat, we regenerate nitrogen-fixing bacteria, mycorrhizal fungi and other beneficial organisms.
How to Improve Soil Using Equipment
It is important to understand not only how to reduce harm to soil and soil aggregates from equipment (which is what S4-tillage is all about) but also how to use equipment to improve soil. Equipment can help improve your soil if it allows more soil-beneficial processes to occur each year.
- Spreader: Applying compost is a great way to build and boost soil health. Soil organisms eat and live in soil organic matter (SOM). SOM helps to cycle and store water and nutrient.
- Flail Mower: Efficient cover crop, green manure and crop debris management adds SOM and nutrients and mulch to the soil.
- Rear-Tine Tiller is used to blend compost, crop and cover crop bits into soil. Shallow introduction of oxygen and debris-rich material allows the soil life to consume and transform it in the A horizon.
- Power Harrow doesn’t invert the soil and can be used to work deeper into the soil profile without mixing the A and B horizons. This keeps soil healthier for more self-regulation. Even the prairies had disturbance from bison, and prairies made great soil!
- Power Ridger reforms Permabeds with in situ compost in paths. By focusing aggressive actions in paths, we maintain the ecosystem mimicry of a natural soil on the bed top.
- Roller/Crimper is used to maximize the leaf litter effect of forests and grasslands with in situ mulch that protects soil from heat/cold temperature extremes, heavy rainfall, snow melt erosion and compaction from equipment. Plus, the debris blocks weeds!
For more on growing with two-wheel tractors, check out Zach’s new book: The Two-Wheel Tractor Handbook, available for pre-order from New Society Publishers.