The Beauty Of Soil

Always be water wise!

Soil is one of the most important resources on earth. Healthy soil is a living ecosystem filled with a variety of micro- and macro-organisms, which underpins food security across the world. Without healthy, well-functioning soils, food availability is threatened, as good quality food filled with nutrients can only come from healthy soils. Good quality soil is also great for water conservation. Water Wise discusses why.

The formation of soil is dependent on the breakdown of the parent rock, and the type of soil results from the type of rock, as well as the size of the soil particles. For example, clay soil is made up of tiny particles that are tightly packed together, with little organic material. Clay soil becomes sticky and saturated when wet but holds few air pockets. Sandy soil, on the other hand, is made up of much larger particles and contains large pockets of air. Water drains through sandy soil very easily, which means it can dry out quickly. Loamy soil is a mix of clay and sandy soils and is a great substrate, as it holds water well while allowing air to circulate. It also contains organic matter and micro-organisms, which makes it a very healthy soil.

Any soil type can be improved by adding compost. Compost, which is organic matter, improves the aeration of soil, as well as its water-holding capacity. Compost can easily be made using kitchen scraps such as vegetable peels, newspaper and grass clippings or leaves that have fallen in the garden. Compost also provides food for soil organisms such as earthworms and enriches soil with nutrients and minerals. Organic mulch like compost is great as it releases nutrients as it breaks down. By improving your soil, you are able to save money on fertilisers and your water bill, as healthy soil retains water for longer.

By identifying the type of soil that you have, you can decide what you need to do to improve it. A simple test to identify the soil type is to add a very small amount of water to your soil, then take a handful of soil in your hand and roll it into an oblong shape. Sandy soil will break up when it is rolled, loam can be rolled but will have some cracks, and clay will be able to be bent when rolled and have no cracks.

Soil type also has a great influence of the type and amount of irrigation used in a landscape or garden. Sandy soils should be irrigated frequently with small amounts of water so that water does not infiltrate too deeply, but rather stays in the root zone of the plant. For clay soils, irrigation should be applied on and off over a longer period of time so that water is able to slowly seep into the soil. Loam soil is the easiest to irrigate, as water stays in long enough for the plants to use it but not so long that soil gets waterlogged.

Soil erosion is a major environmental problem world-wide, as healthy topsoil full of nutrients and organisms is washed away. It can take 200 to 1 000 years to naturally form just 2.5 cm of new topsoil. It is essential to conserve and protect our soils. Healthy soils create a healthy world.

The Gardener