Soil mineralization beyond NPK
Organic gardeners know about soil replenishment beyond nitrogen, phosphorous and potash. Plants may well grow with a shortage of micronutrients but their food quality will be diminished. For optimal human health, optimal soil health comes first.
Unless we adhere to the closed-loop paradigms of permaculture and biodynamics we need to replace the various nutrients that are lost from our garden soil by wind, sale or gift of produce, and sequestering human waste in septic tanks.
I first became aware of the issue of soil remineralization in John Hamaker’s 1982 book, The Survival of Civilization. Hamaker’s thesis is that human activities are accelerating the current interglacial period and we should remineralize soil, as glaciers do, by applying mineral dust to our soils. By doing so we cause vigorous vegetative growth and thereby reduce atmospheric carbon dioxide. (Yes, there is a connection between global warming and glaciation, but that is for another day.)
In addition to obtaining and applying mineral dust we can grow plants with deep root systems that mine minerals from depths far below typical garden plant roots. These include alfalfa, dandelion and trees. While most tree roots are within fifteen feet of the surface, certain oak tree roots have been found in caves nearly 200 feet below the surface. It follows that the yearly dropped leaves and remains of deceased oaks may well contain a store of essential minerals. I typically place a thick layer of fallen oak limb pieces in new raised beds and the last mowing of grass areas each year includes collection of fallen leaves.
Gardeners may easily verify the efficacy of mineral dust application by preparing various soil mixes in identical-sized pots and seeding with fast-growing plants such as radish. I did this about twenty years ago using dust from beneath the rock crusher at Trappist Concrete Products where I was the marketing guy. The monks dug rock and gravel from Bryant Creek and used the screened results in concrete block production. The dust below the crusher was considered waste. I found it to be brown gold.
Soil remineralization works. Who knows, remineralizing your garden soil may revitalize you. Enjoy the journey!