The challenge facing agriculture and farming in the 21st century is to feed a growing population using sustainable farming methods. Many current agricultural practices are not sustainable because they can damage the soil and other parts of the environment. Current methods of farming, particularly in developing countries, often result in desertification and deforestation.
For example, repeatedly growing crops on the same site will require the addition of more and more fertilisers to replace the nutrients lost from the soil. Using large amounts of pesticides can reduce the effect that they have on pests. Also, the rapid destruction of natural ecosystems, such as forests, to provide land for agriculture can cause the widespread extinction of plant and animal species.
Another problem facing agriculture is the loss of genetic diversity in some crop species. This reduces the basic resources available to develop food crops. It also increases the chances of disease affecting large areas of crops, because all of the plants are very similar to each other. The United Nations promotes sustainable agriculture through efficient storage and distribution methods and responsible land management. Techniques for increasing production and conserving soil and water resources need to be applied. Agenda 21 urges the development of long-term land conservation and rehabilitation programmes, by encouraging people to invest in the future through land ownership.