Everything in a watershed is connected to everything else - soils, plants, fish and wildlife. The amount of water slowed and stored by soil and vegetation is a key element in the whole system. Compacted soils don't allow much water penetration. Instead of soaking in, the water runs off, increasing erosion, stripping away vegetation and soils that might otherwise store water. Non-compacted soil absorbs and retains water, releasing it slowly.
Plants protect soil from water and wind erosion, and help the soil store water.
However, compacted soil has less plant growth, which increases runoff even more. The rate of infiltration of water into soil gives an indication of the condition of the soil, its ability to control runoff and support plant growth. The amount if moisture found in soil varies greatly with the type of soil, climate and the amount of humus in the soil. The organic content of soil greatly influences the plant, animal and micro-organism populations in that soil. Decomposing organic material provides many necessary nutrients to soil inhabitants.