| Table 3. MAJOR ENTERPRISES AND OPTIMAL CLIMATE
REQUIREMENTS |
|
Enterprise
|
Temperature (optimal)
|
Rainfall (optimal)
|
Comments
|
| Wheat |
6º C – 29º C |
Min 250 mm (approx 300 – 700mm)within
the growing season of May - Oct |
- Heavy rain in Autumn retards root growth and in early winter it encourages
unnecessary leafiness
- Excessive rain tends to leach out nitrogen from the soil.
- Good rains in Spring and Summer promote growth of grain, while frosts
at these times damage grain and reduce yield depending on the severity
of the frost
- No growth below 3º C
|
| Sugar |
Monthly mean temp above 15º C |
1250 mm/yr |
- Frost will damage plants
- No growth below 15º C
|
| Rice |
Optimal 20º – 38ºC |
|
- Any longer than 10 days below 15º C induces sterility meaning no grain
is formed
- Rice is sensitive to day-length (photo-periodism). Day-length changes
of even 10 minutes can effect some plants.
- No growth below 15º C.
|
| Cotton |
Requires a frost free period of 180 –
200 days |
|
- Low air temp in Spring may cause diseases of seedlings
- Flowering to boll opening is 105 days when daytime temp is 21º C
- Flowering to boll opening is 60 days when daytime temp is 27º C
- Flowering to boll opening is 30 days when daytime temp is 30º C
- Temperatures above 27º C produce strong fibres but less lint in each
boll
- Need a soil temperature of 18º C before seed can be sown and germinate
|
| Coffee |
Needs to be frost free with mean daily
temp of 20º C
|
1800 – 2000 mm/yr |
< 7º C and > 33º C will slow growth
and reduce production. Frosts will damage plants.
|
| Apples |
Requires cool temperature |
|
Cool temperatures initiate development
of flowers
|
| Maize |
21º C |
|
Daily mean temperature needs to exceed
21º C for part of the growing season
|
| Grape vines |
Annual mean temp of 14º –19º C. Annual
range of 4.5º C-8.5º C
|
|
Cooler or warmer temperatures or greater
range in temperatures adversely affect growth and yield. |
| Potatoes |
Temperature requirement
|
|
Needs at least 8º C and no more than 28º
C. Prefers 18º C.
|
| Bananas |
Must have coldest month temp above 15ºC
|
1250 mm/yr |
|
| Sheep |
For best results temperature should not
exceed 35º C for prolonged periods. In cool weather stock need shelter from
cool temperature and winds |
Temperate climate grasses grow where rainfall
is between 250- 800 mm/yr.
Meat sheep need at least 500 mm/yr.
Merinos can manage on 250 mm/yr where temperate grasses have a growing
season of no more than 5 months
|
Climate needs to provide suitable pastures
and suit the animals physiologically
- Rams become infertile with prolonged temperature periods above 35º
C.
- Cold weather after rain can kill wet sheep
- Warm wet summers favour diseases and parasites like fluke. Footrot
becomes an issue over 750 mm/yr and hookworm infestation occurs if rainfall
exceeds 1250 mm/yr.
|
| Cattle |
Breeds are affected by temperature. Brahma
cattle can thrive in daily temperatures of 10º C – 27º C. European
cattle suffer above 15º C. |
Cattle are grown in places where pastures
are either tropical or temperate where rainfall is between <250 - >800
mm/yr. |
- Beef cattle north of the tropics where there is rainfall below 400
mm/yr.
- Dairy cattle need at least 800 mm/yr (Milk yield depends on pasture
production – butterfat can vary from 6000 – 35,000 tonnes
in response to differences in rainfall in the previous 3 months). Milk
yield can also be reduced by heat stress or dry pasture.
|
| Adult pigs |
21º C – 27º C |
|
Lower critical temperature 21º C
Upper critical temperature 27º C
|
| Laying hens |
13º C – 24º C |
|
Lower critical temperature 13º C
Upper critical temperature 24º C
|
| Source: Linacre and Hobbs, 1977 |
