Getting Minerals into Your Soil
Mineral material - what is it?
We talked about the ratios of soil, and how your average pile of soil is 25% water, 25% air, 5% organic material, and 45% minerals. For this example we will use sand as the primary contributor of minerals.
The composition of sand varies in different materials depending on location. The most common component of sand on non-tropical beaches is silicon dioxide in the form of quartz, which is a mineral. (Yes, when you’re walking on the beach, you’re pretty much walking on an expanse of quartz crystals!)
Beach sand from the Tropics contain mostly calcium carbonate, which in the long run will affect your pH - a slight difference to keep in mind. The combination of the organic material and humic acid seems to balance out whether it's silica-dominant sand or beach sand. White sand beaches in Hawaii is mostly chewed up coral that was created by the local parrot fish through millions of years. Parrotfishes use their beaks and the teeth in their throat to chew up coral, and since they don’t have stomachs, their meals pass straight through the long intestine, resulting than little more than sand for poop. Larger parrotfish can produce as much as 840 pounds of sand per year. The soil on the Hawaiian islands tends to be more acidic so it works to add in the more alkaline, calcium carbonate-dominant sand. It’s a good balance and buffer.
Whether you've grabbed minerals from your environment, or brought beach sand or local crushed rock in, it doesn't really matter, because you’re building it with your waste material. You're creating the organic material through your composting and mixing it with mineral material, air, and water. In nature it started off as rock (rock being minerals put together). Natural and biological erosion breaks the rock down so it has more surface area and the creatures are able to make use of it. Most of the time it starts off with a fungal web.
The organic material that you compost will have minerals present, as well as the material that is moved around by the larger subterranean earthworms and brought to the surface. The material of the leaf litter worms is then brought down into the tunnels and break the rock down further from the acidic effect of the humic acid, and the beneficial bacteria in their gut. The material of the leaf litter worms is then brought down within the tunnels of the deep subterranean worms along with it beneficial bacteria, fungal colonies, and humic acid, which all play a part into extending the living web further into the rock mineral subsoil zone and building topsoil.
If we want to create a cubic yard of soil our approach is to bring in certain materials and establish a base where you can compost all of your food scraps by feeding them to earthworms and the other living creatures in the pile. The finished cold compost product with living creatures in it can then be mixed with existing poor quality (inert) soil, sand, or local crushed rock, even coconut husk.
We tend to incorporate aquaponics into the mix, which does not actually need a whole lot of soil to grow in (the plants are able to extract out nutrients directly from the water). The medium we use in our aquaponics systems is the same as the living soil we will make in this course, but instead of adding 40% sand, we add about 10% sand and 30% shredded coconut husk, peat moss, or even saw best, as a medium. This has all the attributes of living soil as a support system for the plants to thrive, allowing their roots the capacity to extract out nutrients directly from the nitrogen processing bacteria of the system.