Organic and Intensive Farming

Recycling elements Nitrogen is very important for all plant life! Animals eat plants. When plants and animals die, they decompose (rot) and the nitrogen returns to the soil. Microbes also break down animal waste so that it can be used by plants again (manure).

Nitrogen Cycle http://www.bbc.co.uk/schools/gcsebitesize/science/21c/food/farmingrev4.shtml (play animation)

The Nitrogen cycle

Harvesting crops When crops are harvested (taken for food), the elements (e.g. nitrogen) are taken away instead of being returned to the soil by dying and rotting. If the elements are not replaced (put back), the next crops will not grow well.

Intensive Farming - chemicals Many different chemicals are used to make plants and animals grow faster Intensive farmers use artificial fertilizers to put elements nitrogen, phosphorus, potassium back into the soil. It is easier to use than manure and smaller quantities are needed, because it contains more of the elements. Artificial fertilizers are spread on the ground or sprayed on the crops.

Intensive Farming - chemicals Problems: They do not just disappear but stay in the plants that we eat, so our food is contaminated with chemicals. Soil used to grow the plants will also be contaminated and have chemicals in it for a very long time. Animals eat the grass , which has had chemicals sprayed on to it, so the chemicals get into their blood and therefore the meat that we eat. Chemicals run off the land into rivers and kill plants and fish.

ORGANIC farming Artificial fertilizers are banned in Organic farming. Organic farmers use animal manure, compost and human sewage, (which has been heated to destroy any harmful microbes) to make their crops grow. ‘Green manure’ is grown – plants are grown, then ploughed in and left to rot. Worms, insects and bacteria underground are always working on making the soil good. By using a process called CROP ROTATION (changing the crop grown each year), the farmer can keep a good soil for many years.

Organic farming It is illegal to sell produce as organic if it hasn’t been produced that way. Farmers must keep to National Standards. Artificial chemicals are banned. Artificial fertilizers and pesticides in the soil have to be below a certain level. Animals must be allowed to move freely, given organic feed but no artificial hormones.

Pest and disease control Pests e.g. aphids, are insects that eat crops. Diseases e.g. potato blight, can kill crops. Pests and diseases can mean that the yield from the crop is small – but pests and diseases can usually be controlled. aphids Potato blight

Intensive farms – Pests and Diseases The crops are sprayed with man-made chemicals to get rid of pests (pesticides or insecticides) and diseases (fungicides)– this means bigger yields and plants that look good. Other chemicals (herbicides) are used to kill weeds (plants not wanted). But the chemicals stay on the plants and could be eaten by humans as well as the pests.

Organic farms-pests and diseases Organic farmers are not allowed to use man-made chemicals for this. Farmers introduce natural predators e.g. ladybirds to eat aphids (biological control). Hedges and grass are left around fields to encourage other natural predators e.g. birds. Crop rotation prevents diseases of a particular crop building up. Natural pesticides may be used. Pest and disease-resistant (stronger) varieties of plants are planted.

Compare these two farms

Advantages Intensive farming Organic farming Bigger yields from land available Fewer workers needed Animals lead happier lives Soil structure is better Fewer blemishes on crops Use of hormones increases meat production Intensive farming Organic farming Produce is cheaper Large numbers of animals kept in ideal conditions More birds and insects Less harmful to environment Antibiotics use keeps animals healthy No harmful chemicals – healthier?

Disadvantages More expensive More blemishes on crops Chemicals stay in soil Man-made chemicals used Intensive farming Organic farming Animals live in crowded conditions Smaller yields Natural predators destroyed Chemicals wash into rivers More farm workers needed Hedgerow habitats destroyed