Organic matter loosens the soil, which increases the amount of pore space. This has several important effects. This means that the sand, silt and clay particles in the soil stick together, forming aggregates or crumbs. Because there is more pore space, the soil is able to hold more water and more air. Plants grown on healthy soils won t be as stressed by drought or excess water.
Water also flows into the soil from the surface more quickly.
With less compaction, it is also easier for plant roots to grow through the soil. Farming practices can decrease organic matter, increase organic matter or maintain organic matter level in the soil. Each time you till the soil, oxygen is stirred into it. This oxygen stimulates or speeds up the action of soil microbes, which feed on organic matter. The more the soil is tilled, the more organic matter is burned off.