Certified organic growers have to adhere to the rules laid down by the governing body. They are restricted in what can be sprayed and what fertilisers to use. However, there is no requirement for a healthy soil organic content. The organic content of the soil makes a huge difference to the nutritional content and taste of the vegetables and provides for much easier management and general health of both the foliage and root system.
To maintain and increase the soil humus content, combining no-till with the addition of organic material – in the form of organic mixtures, manures and compost, all applied to the soil surface – will ensure success. Organic growers should not be tilling the soil and accelerating the depletion of soil carbon, and these fertilisers work very well when placed on the soil surface. They will enter the soil by the action of earthworms and soil microbial life. process is slow and effective. A n additional refinement which is ideal for organic growers is the use of surface mulch. This can consist of many organic materials but dry grass is the most abundant and easily procurable.
Some may worry about weed seeds brought in this way but this mulch layer prevents weeds from growing. If any weeds poke through, throw more mulch on top. This means no weeds, which is extremely important for organic growers who aren’t permitted to use herbicides. he mulch placed over the layer of organic fertiliser will provide perfect conditions to activate the soil organisms which take the manures, etc, down into the soil. The point of contact between the soil/organic fertilisers will also become moist and, with the fertility of the organic content, start to decompose. W hen the soil is partially broken down, the earthworms will spring into action and consume this material, which is greatly enriched when passing through the earthworms before being deposited in the root zone.
Not only will available nutrients be released as a byproduct of the mulch and manures, but the populations of many beneficial microorganisms are increased by this process. s it’s so gradual, this form of decomposition doesn’t cause a negative period in the soil. initially there are few earthworms present, soil fungi will do the job. When more fertilisation is required, a concentrated organic fertiliser, such as that supplied by Talborne Organics, can be placed over the mulch before irrigation. he same can be done with chicken manure but when it comes to compost or kraal manure, it is best done occasionally and preferably when the mulch needs topping up, so the fresh mulch can be placed on top. The more the mulch is decomposed, the greater benefit to the soil’s organic content. – Bill Kerr ((016) 366 0616 or e-mail [email protected]). |fw
