Intensive farming practices include growing high-yield crops, using fertilisers and pesticides and keeping animals indoors. Food production increases but there are unwelcome side effects.
Organic farming bans chemical inputs and has a less harmful effect on the environment but often produces less, more expensive food.
Hydroponics is the production of food using nutrient-rich solution rather than soil.
Food production can be increased by growing high-yield crops, removing other plants and pests and adding fertiliser to the soil. Other intensive farming practices include keeping animals indoors, often in restricted spaces. Many of these practices have unwelcome side effects.
|Remove competing plants from the crop growing area||Herbicide spray||Allows more energy to be transferred to the crop||Reduces biodiversity and may have harmful effect on health|
|Remove animals that feed on the crop||Pesticide spray||Prevents energy being transferred from the crop to consumers||Reduces biodiversity and may poison helpful organisms|
|Keep animals indoors||'Battery' farming||Reduces energy transferred to environment so more energy available for growth||Increased risk of disease, lower quality product, ethical concerns|
Some insecticides don't break down quickly. DDT is an insecticide that can pass up the food chain from insects to small birds, and then from the small birds to birds of prey, like hawks. It can accumulate in the birds of prey, giving them a large amount of DDT. Concentrations of DDT in birds causes weakness in their eggs, and reduces their population. DDT is now banned because of this.
Biological control is an alternative to using pesticides. By releasing a natural predator into the crop growing area, the number of pests can be reduced. This can have unforeseen consequences as the numbers of different organisms in the food web are changed. There have been examples of the predator becoming a more serious pest than the original problem.
Some food products have been grown in artificial environments to increase productivity. Examples include growing tomatoes in glasshouses and salmon in fish farms. The benefits of this method are that the growing conditions can be monitored and controlled to improve productivity.
An extreme form of growing crops in glasshouses is called hydroponics. Soil is replaced by a mineral solution pumped around the plant roots.
Removing the soil means there's no risk of soil organisms causing disease but the plants have to be supported.
Monitoring and adjusting the concentrations of minerals in the solution enable the grower to control growth.
Hydroponics allows crops to be grown in regions where there's little or no soil. Due to the costs involved, hydroponics is used only for high-value crops.