AGRICULTURE, also called farming or husbandry, is the cultivation of animals, plants, fungi, and other life forms for food, fibre, biofuel and other products used to sustain life. Before the 1940s, agriculture was practised on a subsistence basis whereby farmers would grow crops for personal use instead of trade. However, since the 1940s, agricultural productivity has increased significantly, due largely to the increased use of energy-intensive mechanization, fertilisers and pesticides. However, many of the artificial fertilizers used in modern agriculture can cause  environmental problems, for example:
•    Artificial fertilizers and herbicides are easily washed from the soil and pollute rivers, lakes and water courses.
•    The prolonged use of artificial fertilizers results in soils with low organic matter content which is easily eroded by wind and rain.
•    Artificial pesticides can stay in the soil for a long time and enter the food chain where they build up in the bodies of animals and humans, causing health problems.
•    Artificial chemicals destroy soil micro-organisms resulting in poor soil structure and aeration and decreasing nutrient availability.
•    Pests and diseases become more difficult to control as they become resistant to artificial pesticides.
To reduce the negative impacts on the environment, organic farming can be practised. Organic farming works in harmony with nature and involves using techniques to achieve good crop yields without harming the natural environment or the people who live and work in it.
Organic farming provides long-term benefits to people and the environment.
Organic farming aims to:
•    Increase long-term soil fertility.
•    Control pests and diseases without harming the environment.
•    Ensure that water stays clean and safe.
•    Use resources which the farmer already has, so the farmer needs less money to buy farm inputs.
•    Produce nutritious food, feed for animals and high-quality crops to sell at a good price.
Organic farming includes the following practices:

Soil management
The soil is a living system; since the particles that make up the soil contain millions of different organisms. These organisms are very important for recycling nutrients. Adding manure or compost to soil provides food to the variety of life inhabiting it; they in turn change these materials into food – nutrients and organic matter necessary for plant growth. Green manures also provide nutrients and organic matter; these are plants with high nitrogen content that are sown as part of a rotation and are dug into the soil when young.

On the other hand, artificial fertilizers used in large-scale agriculture provide only short-term nutrient supply to crops. They encourage plants to grow quickly but do not feed soil life and do not add organic matter to the soil. It is important to remember, however, that using too much animal manure or nutrient-rich organic matter, or using it at the wrong time, could be as harmful as using man-made, artificial fertilizers. The organic farmer must cultivate the soil at the right time and in the right ways to provide the best living conditions for the soil life and plant roots.

Choice of crops
Each crop and crop variety has its own specific needs. In some places it will grow well and in others it will not. Crops are affected by:
•    Soil type;
•    rainfall;
•    altitude;
•    temperature;
•    the type and amount of nutrients required; and
•    the amount of water needed.
These factors affect how a crop grows and yields. If a crop is grown in a climate to which it is not suited, it is likely to produce low yields and be more susceptible to pest and diseases. This then creates the need to use agrochemicals to fertilise the crop and control pest and diseases.

Rotations
Growing the same crops in the same site year after year reduces soil fertility and can encourage a buildup of pests, diseases and weeds in the soil. Crops should be moved to a different area of land each year, and not returned to the original site for several years. For vegetables, a three to four-year
rotation is usually recommended as a minimum. Crop rotation means having times where the fertility of the soil is being built up and times where crops are grown which remove nutrients. Crop rotation also helps a variety of natural predators to survive on the farm by providing diverse habitats and sources of food for them.

Composting
Compost is organic matter (plant and animal residues) which has been rotted down by the action of bacteria and other organisms, over a period of time. Materials such as leaves, fruit skins and animal manures can be used to make compost. Compost is cheap, easy to make and is a very effective material that can be added to the soil as fertilizer.
Compost improves soil fertility by adding nutrients and by making it easier for plants to take up the nutrients already in the soil. This produces better yields.
Mulching
Mulching means covering the ground with a layer of loose material such as compost, manure, straw, dry grass, leaves or crop residues.
Mulches have several effects on the soil which help to improve plant growth:
•    Decreasing water loss through evaporation;
•    Reducing weed growth by reducing the amount of light reaching the soil;
•    Preventing soil erosion;
•    Increasing the number of micro-organisms in the top soil;
•    Adding nutrients to the soil and improving soil structure; and
•    Adding organic matter to the soil.