Irrigation

Irrigation

improve crop quality
aid harvesting in dry soils
reduce capping
aid germination
maintain/increase yields
crop requirement varies
1. climate
2. crop
  1. potatoes
    1. june/july
      1. transpire 25-35mm/ha/week
        equivalent to 250,000- 350,000litres/ha/week
    2. apply 5mm at SMD=10mm to avoid common scab
      1. BPC, 1999
    3. 400mm per season
      1. upto 200mm from irrigation (Shrops)
3. cultivar
4. length of growing season
5. soil type
6. soil structure
7. daily weather
soil water reserves deplete
1. gravitational
2. evapotranspiration
  1. evaporation
  2. transpiration
increase nutrient availability
low soil moisture
1. stomata close
2. transpiration falls
3. CO2 uptake reduced
4. DM reduces
5. wilt and die
water uptake factors
1. air temp
2. relative humidity
  1. high reduces transpiration
    1. low increases
3. wind speed
  1. low=low
    1. high=high
4. solar radiation
5. size/ development/ age
6. soil
  1. water status
  2. structure
MAFF, 1988
1. approx. 17% AWC for all topsoils and subsoils
  1. silt loam = 23% & 22%
  2. sands = 12% & 7%
  3. peats = 35% & 35%
Withers and Vipond 1974
1. infiltration rate decreases over time
  1. reaches terminal rate
    1. 55mm/hr sand 30mm/hr loam 5mm/hr clay
OM increases pore volume and size
1. thus increasing infiltration and water capacity
ADAS Irrigation best practice guide 2003

Resource summary

	Created by labradorlass almost 11 years ago