It must be noted, that rocks also possess fertility to some degree. Investigations show that even the hardest rock massifs a are inhabited by various organisms. Lichens develop on their surfaces and often cover large spaces on mountain tops. The upper layer of rock massifs, the so-called weathering crust, is saturated with bacteria and algae, as well as fungi, actinomycetes, protozoa and other organisms. According to our data, in the upper layer of basalt rocks, the bacteria in one grain of substrate number from some tens of thousands to millions.
Rocks differ in their fertility.
Some of them are densely overgrown with lichens and microorganisms, others are sparsely covered. Tens of thousands to hundreds of millions were counted in one gram. The principal property of the soil fertility is determined by biological factors, mainly by microorganisms. The development of life in soil endows it with the property of fertility. Soil is created by microorganisms.