What role does soil and human made factors play forf agriculture geography?
Answers
1. Temperature:
Most plants cannot grow if the temperature falls below 6°C or the soil is frozen for five consecutive months. As a consequence many areas are unsuitable for crop cultivation.
2. The growing season:
The number of days between the last frost of the spring and the first of the autumn. Different crops require different lengths of growing season. Cotton needs 200 days so could not survive in a British climate. Cereal crops are grown in the South-east of Britain as this is the area most likely to meet the necessary growing season. The shorter the required growing season the further north that crop can be grown. Oats can be found in Northern parts of the UK because they have a very short growing season.
Crops
3. Altitude:
This affects temperature so it also affects farming. In the Alps for example you will find dairy farming in valley bottoms and coniferous forestry further up.
When temperatures are consistently high with sufficient precipitation high yield crops such as rise can be grown. These have the added advantage of producing up to three crops a year.
4. Rainfall:
Water is obviously a key factor in plant growth. The greater the average temperature the greater the amount of water required for plant growth. Seasonal variation is important as different crops require water at different times. Coffee for example must have a period of drought before and during harvest whilst maize would benefit from heavy rain in the same period. A farmer is therefore looking for rainfall reliability so that he can select the most appropriate crop for the area.
Rice is the principal crop in the tropics because it requires substantial quantities of water, is a very high yield crop and has good nutritional value. With the addition of consistently high temperatures it can also produce two or three crops a year.
In the Mediterranean crop growth is affected by the summer drought despite high annual rainfall. The rainfall is very high in winter months but infiltration rates are comparatively low. In summer temperatures are very high, encouraging high rates of evapo-transpiration and consequently very dry soil and a low water table. There is a soil moisture deficit. These conditions are not conducive to plant growth.
Crop growth
5. Wind:
Wind can have a destructive effect on crops. At its most severe a hurricane can physically destroy thousands of acres of farmland. Less severe but also harmful are the winds that dry soils so reducing moisture and increasing the potential for soil erosion.