Module Grown Strawberry Nutrition Programme
Patrick Murphy Boro Valley Fruits Ballymackessy Cross, Enniscorthy, Co.Wexford
The water analysis indicates soft water, with no need to add any acid. The calcium level in the water is very low (8 mg/l). This means extra calcium must be added to the water, or strawberries of poor shelf life will result.
Levels of sodium, chloride and the overall conductivity, is low. This indicates that the water is a suitable water supply for fertigating strawberries. The level of trace elements in the water is low and can be ignored.
To correct the low calcium level, 12 kg of Calcium nitrate was added to a separate tank and 200 litres of water added. This was diluted to 1:100, using a separate in-line Dosatron. Never add the Calcium nitrate to the main feed tank, or a sludge of calcium sulphate will form!! The additional calcium nitrate will supply 114mg/l calcium, giving a total of 122mg/l including the water supply. The target is around 100-120 mg/litre calcium.
The second tank (main feed tank) contains 13.5 kg of 7-6.3-34 hydroponic feed and 2.0 kg of 10-52-17 feed. This is also made up to 200 litres. At green fruit stage onwards the 7-6.3-34 feed is increased to 16.0 kg per 100 litres of mix, keeping the 10-52-17 feed constant. This gives 149-mg/l nitrate-N during the main fruiting stage. The Kinsealy target level of nitrate-N for module grown strawberries is 150 mg/l.
During picking stage 2.0 kg of potassium sulphate is added to the main feed tank. This is known to improve fruit flavour.
A runoff of 25% is the target during the main growing phase of the crop. If the input from 2 drippers is measured, and the output from 8 drippers is also measured, and the volumes are the same, then this equals to 25% runoff.
Water sample: P Murphy
| Test | Water Result (mg/l) | Test | Water Result (mg/l) |
|---|---|---|---|
| pH | 6.4 | EC | 175 uS/cm |
| Phosphorus | 0.1 | Sulphate | 9.9 |
| Potassium | <1 | Boron | <0.01 |
| Calcium | 8.2 | Copper | <0.01 |
| Magnesium | 9.6 | Manganese | <0.01 |
| Nitrate-N | 6.2 | Zinc | 0.02 |
| Iron | <0.01 | ||
| Iron | <0.01 | Carbonate | <0.1 |
| Sodium | 12.3 | HCO3 | 28.5 |
| Boron | <0.01 | ||
| Chloride | 19.3 |
