The organic movement broadly believes that crops and ornamental plants should be produced with as little disturbance as possible to the balance of microscopic and larger organisms present in the soil, and also in the above-soil zone. This stance can be seen as closely allied to the conservation position, but with the difference that the emphasis here is on the balance of micro-organisms. Organic growers maintain soil fertility by the incorporation of animal manures, or green manure crops such as grass–clover leys. The claim is made that crops receive a steady, balanced release of nutrients through their roots; in a soil where earthworm activity recycles organic matter deep down, the resulting deep root penetration allows an effective uptake of water and nutrient reserves.
The use of most pesticides and quick-release fertilizers is said to be the main cause of species imbalance, and formal approval for licensed organic production may require soil to have been free from these two groups of chemicals for at least 2 years. Control of pests and diseases is achieved by a combination of resistant cultivars and ‘safe’ pesticides derived from plant extracts, by careful rotation of plant species, and by the use of naturally occurring predators and parasites. Weeds are controlled by mechanical and heat-producing weed-controlling equipment, and by the use of mulches. The balanced nutrition of the crop is said to induce greater resistance to pests and diseases, and the taste of organically grown food is claimed to be superior to that of conventionally grown produce.
The organic production of food and non-edible crops at present represents about 5 per cent of the European market. The European Community Regulations (1991) on the ‘organic production of agricultural products’ specify the substances that may be used as ‘plant-protection products, deter-gents, fertilizers or soil conditioners’ (see pages 148 and 194). ‘Conventional horticulture’ is, thus, still by far the major method of production and this is reflected in this book. However, it should be realized that much of the subsistence cropping and animal production in the Third World could be considered ‘organic’.
The use of most pesticides and quick-release fertilizers is said to be the main cause of species imbalance, and formal approval for licensed organic production may require soil to have been free from these two groups of chemicals for at least 2 years. Control of pests and diseases is achieved by a combination of resistant cultivars and ‘safe’ pesticides derived from plant extracts, by careful rotation of plant species, and by the use of naturally occurring predators and parasites. Weeds are controlled by mechanical and heat-producing weed-controlling equipment, and by the use of mulches. The balanced nutrition of the crop is said to induce greater resistance to pests and diseases, and the taste of organically grown food is claimed to be superior to that of conventionally grown produce.The organic production of food and non-edible crops at present represents about 5 per cent of the European market. The European Community Regulations (1991) on the ‘organic production of agricultural products’ specify the substances that may be used as ‘plant-protection products, deter-gents, fertilizers or soil conditioners’ (see pages 148 and 194). ‘Conventional horticulture’ is, thus, still by far the major method of production and this is reflected in this book. However, it should be realized that much of the subsistence cropping and animal production in the Third World could be considered ‘organic’.
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