Potassium deficiency on orange made worse by
- Acidic soils (low pH)
- Sandy or light soils (leaching)
- Drought conditions
- High rainfall (leaching)
- or heavy irrigation
- Heavy clay (illite) soils
- Soils with low K reserves
- Magnesium rich soils
Potassium is important for
- Larger leaf area maintaining through season
- Shoot growth more vigorous
- Fruit load increase/benifit to yield
- Fruit are larger with better colour, skin texture and flavouring (more acidity)
- Level of vitamin C increases