In soil, particles group together to form aggregates.
Usually, the soil will be somewhat granular, and consist of porous granules held together by organic matter and clay. These granules are rounded and vary in size from small and pellet-sized to the size of a large pea.
If there is not much organic matter in your soil, and the soil has been continuously cultivated, there may be larger, more massive and harder clumps.
The structure of your soil is related to the movement of air and water within it. When growing anything, in any type of soil, it is vitally important that there is movement of air and water. Poor soil structure inhibits their movement.
If you think about it, it’s easier for water to enter a granular soil than one with little or no structure.
And, since plant roots move through the same paths as air and water, a good soil structure will promote good root development. Conversely, bad soil structure will discourage it.
You can promote good soil structure by adding organic matter and working it into the soil.
Plants also change the structure of the soil. Plant roots act as support for the plant and also gather food and water.
As they grow, the roots will enlarge channels through the soil. When they die and decay, the channels remain.
In addition, bacteria, mold, tiny plants and micro-organic animals grow along the root channels, adding to the structure of the soil.
When these micro-organisms die, they add nutrients to the soil.
See also
Colors and Textures in Desert Soil
Caliche - Hard Desert Gardening
