Organic matter in a soil is made from the leaves, fruits, and branches that continually fall from a plant onto the soil, and in the soil, from roots that die off, and other organic materials that leak from living root cells during a plants normal life cycle.
Organic matter is essential to all soils; it is the vital component that affects the soil and the plants growing in them, in the following ways:
It improves the soil structure and therefore the supply of oxygen and water to plants
It is a source of nutrients for plants, which are released as the organic matter slowly decomposes
It regulates the supply of nutrients, by holding them in readily available forms and reducing losses in drainage waters
It helps to buffer soils against rapid changes in pH
It helps to control root diseases.
Decomposition of the plant materials varies; the softer parts become unrecognizable quicker than the woodier parts of the plant. The process of decomposition is mainly caused by a large number of microorganisms working in the soil.
As part of the natural cycle, the plant products are consumed, and then released as waste products which are structured in a way that makes nutrients available to the living plant roots. In a balanced ecological system, organic matter is the original slow-release fertilizer, and plant growth can be sustained almost indefinitely through recycling, but where rapid growth is expected, additional nutrients are required.
Fertilizer is the usual course of action, but if the soil carries a large percentage of organic matter, then the decomposing material should be able to supply enough nutrients on a daily basis. In urban areas it is difficult to keep up the level of organic matter because gardeners like to tidy up the plant “litter” in their gardens, and lawn clippings are always cleared away.
If you are happy to leave the plant litter where it has fallen in your garden, just ensure that you have lots of very healthy plants that will be continually replenishing the soil, or in the case of most gardens and sport fields, it will be necessary to bring in and replenish the organic matter (compost) in a garden, which will help to speed up the natural process and therefore ensure enough nutrients are being released.
Bennie Diedericks
