Plants produce these complex nutrients from water, air, soil and sunlight. The type of agriculture which is the norm in Britain developed since the second World War. It is an industrial process with a linear flow of nutrients and characterised by its use of synthetic chemicals such as pesticides. When the crop is harvested, the nutrients accumulated by the plant and eaten by humans and animals are not returned to the soil but are eliminated as waste. The soil is viewed as nothing more than an inert container.
High yield is the goal.
Organic farming is based on ecological principles of the cyclical flow of nutrients and does not involve synthetic chemicals. The soil is viewed as an essential part of the process. Microorganisms in the soil feed on the soil organic matter and make the inorganic part available to plants. The fertility of the soil is maintained by returning nutrients removed by the plant in the form of compost and manure and by a system of crop rotation in which crops which remove more nutrients alternate with crops such as legumes which remove less and add some. There are clear differences between the two systems of agriculture in philosophy, sustainability, effect on the environment and wildlife, and amount and type of pollution they generate.