Explain two ways in which the yield of some food crops can be increased. [3+3]

Yields is the amount of food produced off a given area of land. Methods of yield increase include increased use of fertilisers, pesticides, irrigation and adoption of high-yielding varieties. A popular method is that adoption of GM crops (genetically modified crops are foods derived from organisms whose genetic material (DNA) has been modified in a way that does not occur naturally). Yields might increase due to the use of GM crops, as this allows the creation of crops that are better resistant to pests and bad weather conditions, meaning farmers are able to produce more crops off the same area of land, as pests usually reduce the yield of crops. In parts of Australia farmers produce a popular GM canola which has been modified to grow in salinized soils. Few other crops are able to grow in such conditions. If GM canola was not available to the farmer the land would likely be unused. Another method is increased use of fertilisers. Yields might increase because of an increased use of fertilisers, as this allows crops to receive more nutrients and therefore, more crops will be able to be produced in a same given area. To grow plants require chemical compounds such as nitrates from the soil. However, with land that has become over farmed these nutrients can be leached from the soil. Thus through fertilisers these nutrients are reintroduced. These can also be inexpensive such as a natural fertilisers for example animal faeces or mulching.