Balancing Soil Minerals
The Soil Pyramid
What is soil, really?
Soil is a result of life. Without life, soil would be regolith: weathered rocks.
Soil is the product of millions of years of life on Earth and it sustains us all.
Gardening and farming are intensive and fundamentally unnatural processes. In a natural system like an old growth forest for example, plants grow in exactly the environment they have evolved to grow in and they recycle nutrients in place.
In cultivated systems, non-natives are generally introduced and the nutrients in the food usually leave the farm or garden, even if the residue is composted and returned. “Sustainable agriculture” sounds good but how can it be achieved in practice? A truly sustainable system would require recycling of all nutrients, including human manure. And if the fundamental fertility was not available in the system, it would need to be brought in from outside or else the consequences of deficiency would be felt.
Soil nutrient deficiencies are common throughout the world. In 1990 the Food and Agriculture Organization of the United Nations reported on 190 agricultural soils worldwide (note that your soil may not even be considered “agricultural”). They found that 73% of these soils are deficient in phosphorus, 55% are deficient in potassium, 31% are deficient in boron and 49% are deficient in zinc. These are deficiencies by conventional standards, not the higher standards required for nutrient density. Most, if not all soils need additional minerals in order to optimize nutritional balance of the food grown on them.
Nutrient deficiencies in the soil translate into nutritional deficiencies in the animal that eats the food grown on that soil. Although we now tend to eat food grown in diverse places, the nutritional content of most food, even organically grown food, is marginal at best. See our book for the evidence linking soil fertility to human health.
Leibig’s barrel and the law of the minimum
The great 19th century chemist, Justis von Liebig, found that plant growth is limited by the least available nutrient. Just as the barrel bearing his name shows, the lowest stave (the least available nutrient, depicted as the lowest piece of wood in the barrel) will limit the amount the barrel will hold (the growth of the plant). Once the least available nutrient is supplied, another nutrient becomes the least available.
As gardeners and growers, we often are searching for the silver bullet… that one thing that will make our gardens flourish. You will hear a lot of stories about other people’s silver bullets. They will tell you what worked for them, in their situation. But everyone has their own barrel and their own lowest stave. You’ll need to see what works for you, in your situation.
If a little is good, more is better? Not really…
The trouble with Liebig’s barrel is that it doesn’t tell the whole story. While it correctly illustrates the limiting factor, it reveals nothing about the soil balance needed to allow plants to grow to their full potential.
Our concern is helping you grow food of the highest nutritional density.
This means balancing the soil mineral reserves, building the capacity of the soil to hold and distribute nutrients and enhancing the means with which plants take up nutrients, both biologically and directly.
Home gardens and small farms can be a great source of nutrient dense food. They are usually fairly small in area, and so do not require truckloads of mineral nutrients. There are many, many benefits to the garden farmer and the local community. And if you are going to be growing and selling your own food, why not grow the best?
The cost of external inputs is a major concern for farmers who need to make a living from their crops. It pays to make sure that any mineral amendments applied are of benefit and take the soil in the direction of balance. If you are going to be adding amendments, why not make sure they are “just the right ones”?