Garden with Insight v1.0 Help: Tool action functions: mix soil

When you mix the soil, this is what happens. A proportion of each soil layer down to the tool's depth is moved into to a temporary holding layer. The proportion of soil taken from each layer is the area of the tool divided by the area of the soil patch. All of the solid quantities in the removed soil are added to the holding layer -- organic matter, flat residue, nutrients (all forms), clay, silt, sand, and rocks. By adding up each of these quantities from the different soil layers we are mixing them. Then the combined amount of materials is added back to the soil layers it was taken from according to their thicknesses. This method is like pounding a hollow pipe into the soil and pulling it up, then dumping the soil inside it into a big tub, mixing the soil thoroughly, and dropping the mix back into the hole.

Some other things that change during mixing of the soil are:

Bulk density is increased in each affected soil layer. The bulk density is brought closer to the settled bulk density, which is that when the soil is completely settled. This is because although the soil may seem more fragmented after you cultivate it, you have broken up the existing soil structure and it is more easily compacted afterward.
The soil weight in each layer is recalculated from the bulk density after the change in bulk density is calculated.
The P sorption coefficient, which regulates the equlibrium between labile and mineral P, is mixed along with the soil quantities, but in a more complex way based on the amount of soluble P in each soil layer.
The soil water constants (wilting point, field capacity and porosity) are adjusted for changes in rock content in each soil layer during mixing. The amount of soil water in each layer is not mixed.
Some of the standing dead residue on plants in the soil patch is mixed into the flat residue in the top soil layer, and well as some of the mulch flat residue.

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