Remineralization for Soil Health
1. The Importance of Minerals
Remineralization is the process of adding ground up rock (Rock Powder) to agricultural land. Rock-forming minerals of igneous and metamorphic rocks contain most of the nutrients required by higher plants for growth and development, and as such, Rock Powder fertilizers provide a source of nutrients to depleted top soil.
Initially, the potential of Rock Powder as a fertilizer was linked to the chemical view of fertilization and was approached as a geochemical problem where bulk soil solutions not in equilibrium with fresh primary minerals leading to dissolution and nutrient uptake. Most rocks are composed chiefly of silicon and aluminum, both of which are bound tightly to oxygen. Plants don’t need much silicon and aluminum. What they require a lot of are three elements— nitrogen, potassium, and phosphorus, to build roots, stems, and leaves. Plants also need other major nutrients, like calcium and magnesium, which are abundant in some types of rock and generally don’t limit plant growth. Other elements contained within rocks are considered micronutrients because plants need far less of them. Plants stockpile and concentrate critical micronutrients weathered out of rocks. Among these micronutrients are metals like zinc and iron, which plants fold into complex molecules that serve specialized purposes in their shoots, roots, leaves, seeds, and fruits.
Slow dissolution rates of minerals, however, inhibit the use of Rock Powder in agriculture unless suitable soils are identified and optimum Rock Powder properties developed. In soils, mineral dissolution is enhanced by disequilibrium between soil solution and mineral surfaces through the removal of ions by processes such as leaching and nutrient uptake. Rhizosphere processes and other biological activity further enhance mineral dissolution through the release of complexing organic compounds which react with mineral surfaces.
What was missing however, was a much easier, and effective, way of getting to the minerals, and it involves a biological, not chemical, approach.
2. The Role of Microorganisms in Extracting Mineral Nutrients from Mineralized Rock Powder
Plants absorb the metabolic products of soil organisms that feed on and break down organic matter and rocks. When microorganisms decompose dead plants and animals, elemental building blocks are put back into circulation, including nitrogen, potassium and phosphorus as well the as the assorted micronutrients important for plant health. Moreover, microbes deliver nutrients right back to where they are needed – a plant’s roots.
Micronutrients are generally found in insoluble compounds within the soil, locked and unavailable for plants. Certain microbes help pry these elements loose. However, modern agriculture destroys microbes that can make these micronutrients available. Mycorrhizal fungi especially are incredibly valuable, and highly efficient, in enhancing the plant uptake of micronutrients. Recent research suggests that mycorrhizal fungi mobilize essential plant nutrients directly from minerals through excretion of organic acids, enabling plants associated with the fungi to utilize essential nutrients from insoluble mineral sources
3. The Role of Mineralized Rock Powder on Microorganisms
Remineralization influences microorganisms because of both composition and particle size. The composition of Rock Powder fertilizers develops microhabitats that differ in mineral composition and size. Different minerals are colonized by distinct microbial communities and preferential colonization of minerals containing nutrients provides “hotspots” of activity. Applying different combinations of mineral rich Rock Powder to soil influences bacterial communities in bulk soil. The role of minerals is thus two-fold; to provide nutrients for the plant, and to provide opportunities for microbial health within the soil, making them resilient and resistant to attack.