Water in the soil

Soils vary greatly in their ability to hold water. Sandy soils, also known as light soils, are easy to cultivate but have a low ability to hold water - incoming rainwater tends to flow very quickly through a sandy soil and little is held in the soil to meet the needs of crops and other plants. For this reason they are often referred to as droughty soils and plants growing in them will either need little water or the water supply has to be supplemented by irrigation. Plants that do become established in sandy soils will tend to have a large rooting system capable of prospecting for water.

Clayey soils, by contrast, are capable of holding strongly onto any water entering the soil. This is because there are lots of very fine pores in clay soils and once the water penetrates into them it is held on the edge of the fine clay particles from where it is released only gradually to plants. Clay soils have a high waterholding capacity and in periods of heavy rain can become waterlogged, making it difficult to farm.The ideal soils from a management point of view are the loams, i.e. those with a mixture of particles of different sizes and a mixture of different sizes of pores, which means they can store water, allow reasonable soil drainage so as to avoid waterlogging, and allow ready prospecting of the soil by plant roots.