Key Points
- To better understand irrigation management knowledge of the principles of soil water are critical.
- The amount of water available can be described by saturation, field capacity, permanent wilting point (PWC) and available water.
- Saturation of a soil is where all soil pores are filled with water.
- Field capacity is when excess water has drained (1-2 days).
- Available water capacity is the amount of water between field capacity and PWC.
- Evapotranspiration rates for Canterbury vary between 1.6mm and 4.9mm per day.