2. CLIMATIC CONDITIONS
Best results from macadamias are achieved at
temperatures between 20° and 25°C. Soil temperatures
less than -1°C can severely affect young trees and frosts
of -6°C will kill young trees and damage flowers and
foliage of older trees. Prolonged exposure to over 35°C
will also cause stress.
Average annual rainfall should be at least 1200mm,
otherwise irrigation is required. Between 1500mm
and 2500mm is ideal for most soils.
3. • < 20 % area under Mac production
have rainfall >1200mm/yr
• All the Northern areas - dry winter
and spring
4. IMPORTANCE OF IRRIGATION
Yield !!! = profit
In a season of below average rainfall (Clunes, Northern New South Wales,
Australia), irrigation increased yield of Macadamia var. 246 from 10.54 kilograms
per tree of nut in shell (10 % moisture nis) for non irrigated trees to 20.79
kilograms (10% moisture nis) for irrigated trees, an increase of 97 %.
- Col Peak and Ned Sutherland
South Africa
Average Dry land yield = 2t/ha
Irrigation = 3 to 5 t/ha
5. CRITICAL PERIODS FOR NO WATER STRESS
Flowering
Fruit set
Exponential fruit growth
6. WATER REQUIREMENTS
• Total water requirement (effective)
• 950mm to 1100 mm/ha/year
• 32 000 liter/tree/year (313 trees/ha)
• Max daily water use (January)(mature trees)
• 6 mm/ha/day
• 190 liter/tree/day (313 trees/ha)
• Rainfall
• 750 mm to 1400 mm
• 30 to 50% effective
• Irrigation supplement
• Varied from 400mm to 1000 mm/year
7. IRRIGATION TYPE
• Dry land ? around 50 %
• 10% increase from 2 ton/ha(DIS) = 200 kg
• 200 kg (DIS) @ $2,5/kg = $500/ha
• This is enough to finance the capital cost plus pay for the running cost of irrigation
• Micro
• 90% of irrigated area
• Drip
• Very promising but still small area
8. SCHEDULING
• High frequency
• Very shallow root system
• Proteoid roots, also known as cluster roots, are plant roots that form clusters of closely spaced
short lateral rootlets. They may form a two- to five-centimetre-thick mat just beneath the leaf
litter. They enhance nutrient uptake, possibly by chemically modifying the soil environment to
improve nutrient solubilisation.[1] As a result, plants with proteoid roots can grow in soil that is
very low in nutrients, such as the phosphorus-deficient native soils of Australia.
• Thick mulch layer
• Less the 20 % depletion of easily available water
• Keep top soil moist and subsoil moist to dry
