In permaculture, microorganisms in the soil have a crucial role to play in maintaining the health and well being of plants that are grown in that soil. Plants feed on nutrients that are provided by such microorganisms. By providing chemical fertilizers, tilling the soil a large proportion of such useful microorganisms are lost thus leading to the degradation of 'life' in the soil and thus plants suffer on the long term or become addicted to and dependent on the chemical fertilizers. Permaculture seeks to break such dependence and free plants and their carers making agriculture more sustainable.
Soil, Water and Plants
It is interesting how the size of particles in the soil, for instance sand having large particles, can affect the water holding capacity of such soil and the ability of plant roots to move and absorb water from it. Such things can be measured in order to determine the optimal conditions for a plant to grow and develop. It is interesting how such measurements can aid in planning for agriculture.