Monday, January 25, 2016

Soil 302: Exhausted

Conventional agricultural soils are exhausted because we don't replace both macro and micro minerals removed by heavy cropping.

Settlers on the prairie would homestead for 7-10 years, exhaust the soil and move on. We avoid the moving on scenario by applying macro minerals N-P-K-Ca. With this regimen the plants look good but the human body and critters we grow for food need  92 minerals.

So what about the other 88 minerals.

Well for the most part we ignore them and don't refill the mineral "gas tank" like we should. Prairie soils weather at about the same rate as minerals are leached out of the soil or removed by grazing. Well maybe they aren't really removed, they are translocated or shuffled around by herds of grazing animals. Let's look at how that worked.

Grazing herds would graze the lowlands but then would seek out the high points on the hills for rest and a vantage point to look for predators. When they were ready to move on they would defecate on the hill tops and the nutrients had been transported "up the hill".

Also, deep rooted prairie species would bring nutrients to the soil surface from 20-30 feet deep. When the top growth would die back at the end of the season the minerals were then available on the surface.

These mechanisms plus normal soil weathering kept the soil tank topped off at all times.

In modern agriculture we remove the grain, hay and stubble and transport it off the farm. In this model the minerals are lost and eventually the soil is exhausted.

If the minerals aren't in the soil they can't be in our food either. So our vegetables are deficient in what it takes to maintain health and prosperity.

No comments:

Post a Comment