Thanks to Phil Watson for another donation - an expert perspective on healthy soil.
The chemical approach to feeding plants is through the method of dissolving liberal amounts of soluble fertilizer in the soil water, which is then taken up by the plants. Whether they need it or not, the roots continuously absorb the chemicals in the soil water, resulting in force feeding of the plants and a consequent greater susceptibility to disease and insect attack.
However, the organic approach regards natural fertilizers as food for the soil organisms. These essential soil organisms, which include, bacteria, fungi, algae and earthworms along with the natural enzymes that speed up the whole nutrient supply process, will provide the nutritional needs for healthy plants. They are very sensitive to soluble chemical fertilizers, which will inhibit or destroy both the enzymes and/or micro-organisms, causing a disrupted soil food web.
For this complex process to function efficiently, sufficient amounts of humus and trace elements are needed.
Trace elements are easily obtained by adding rock dust to biologically active soil or directly into your compost heap if your soil is poor. Seaweed or seagrass, which contain the complete spectrum of elements found in the sea, are also excellent trace element and humus sources. They can either be added to the compost or used directly as a mulch, without washing off the salt or sand.
Compost should be regularly applied to build up and maintain the soil humus levels to >5%.
Remember, that the humus is decomposed constantly by the micro-organisms during the growing seasons. It is also lost due to dry, hot conditions as well as excessive cultivation and lack of oxygen from poor drainage or soil compaction.
In summer provide adequate moisture and use organic mulches to add extra humus whilst decreasing the soil temperature. It also reduces the temptation to cultivate the soil.
In winter, cereal cover crops pump out the water from poorly drained sites allowing oxygen back into the soil keeping the micro-organisms happy. Cover crops such as rye corn, oats, buckwheat and barley are ideal for this purpose. Legume cover crops such as tick beans, grey peas, broad beans, vetches, red clover and lupin dislike waterlogged conditions, and should be used once the drainage has improved.
Finally, the old saying that every organisms waste is another organisms food remains the theme to successful organic gardening.