Crop
Irrigating potatoes on sand
Adopting good irrigation principles and using the following table to schedule irrigation your potato crop will meet crop demand for water and promote good even growth. Problems such as reduced yields, reduced specific gravity and the incidence of hollow heart and other tuber defects will be minimised.
Water requirement (mm) = Evaporation (mm) x Crop Factor
| Table 1: Crop factors for potatoes growing on sand | ||
| Growth Stage | Week | Crop Factor |
| Sowing to emergence | 0 - 3 | 0.9 |
| Emergence to full canopy cover | 4 - 6 | 1.3 |
| Full Growth to maturation | 7 - 16 | 1.5 |
| Maturation to senescence and harvest | 16 - 20 | 0.9 |
In warmer weather on sand it is normally necessary to water daily. If the daily water requirement exceeds 8 mm irrigate twice. Apply the bulk of the water early to mid morning; late afternoon watering promotes disease and applying water at night can be wasteful.
Split applications may be needed to cool a crop or control wind blown sand but at least one application should be sufficient (6mm) to penetrate the soil to depth. During the cooler months, additional night or early morning watering may be necessary to control frost.
The above table relates to crops grown on Karrakatta sand low in organic matter at the Medina Research Station and represents a guide for achieving optimum yield on this soil type.
