Soil and Water
There is an important link between soils and water, the quality
of our water being closely linked to the quality of the soils.
Water in the soil supplies plants and animals, but acts also to
transport nutrients and other important substances from the soil
to plants, microbes etc.
However, too much water can have damaging consequences. For example
excessive rainfall can result in problems like soil erosion, and
can waterlog plants and vegetation thus depriving their roots of
air. Thankfully, certain properties of soil can reduce the possibility
of this happening.
There are several stages in the interaction of water with soil.
Firstly, it enters the soil through a process known as infiltration – the
higher the rate of infiltration, the more water is soaked up by
the soil, and will be available to plants. Also, less water will
run off the surface, eroding the soil, and washing away nutrients.
Secondly, water is stored in the soil and released when required
by plants. Following this, drainage (percolation) of the water
occurs when there is too much for the soil to cope with – the
excess water drains freely out of the soil, taking with it dissolved
and suspended material in a process, known as leaching. Soils can
vary greatly in their ability to perform these functions.