Factors influencing farming: Physical or Environmental factors

Physical factors also affect agriculture. Image credit irinnews.org

Temperature

• These are critical for plant growth because each plant or crop type requires a minimum growing temperature.
• In temperate latitudes this is 6°C. Below this members of the grass family, including cereals, cannot grow.

Growing season

• Growing Season is the number of days between the last frost of spring and first frost of autumn.
• Growing season varies by crop; Cotton needs 200, Spring Wheat needs 90.

Rainfall/water supply

• The mean annual rainfall for an area determines whether farming is likely to be based upon tree crops, grass, cereals or irrigation.
• Few crops can grow when there is less than 250mm a year.
• Seasonal distribution is more significant than annual total rainfall.
• Long steady periods of rain allow the water to soak into the soil.
• Short heavy downpours lead to surface runoff and soil erosion.

Latitude

• Growth is controlled by decrease in temperature at height.
• In Britain few grasses (including hay) can produce commercial yields above 300m.
• In warmer latitudes wheat can ripen at 3000m.

Wind

• Wind increases evapotranspiration rate.
• This allows the soil to dry out and to become vulnerable to erosion.
• Some winds are beneficial to agriculture, for example Chinook.
• Chinook winds are a warm dry wind which blows down the east side of the Rocky Mountains in Canada at the end of winter.
• This melts snow on the prairies, lengthening the growing season.

To access more topics go to the O Level Geography Notes page