Minerals are removed from the soil in harvested crops or forests or by leaching aggravated by erosion. With the loss of minerals, soils become impoverished. Soil microorganisms are then unable to obtain the nutrients they need to reproduce. As a result the amount of stable humus produced is reduced thus rendering the soil increasingly unable to sustain plants (and especially trees) and animals.
When fertilizers are added to a crop, the plants absorb not only the extra nitrogen, phosphorus and potassium from the fertilizer, but also proportionately increased levels of micronutrients from the soil, including zinc, iron and copper. Over years, the soil becomes deficient in these micronutrients. Lack of them inhibits a plant's capacity to absorb nitrogen, phosphorus and potassium.
Demineralization leads to the ultimate impoverishment of the soil on which the fate of the biosphere depends.