Many crops exhibit calcium deficiency due to its lack of mobility in the plant, or imbalances with other nutrients such as nitrogen, potash or magnesium.
Transportation of calcium within the plant is primarily via the xylem and is thus related to the transpiration rate. Calcium deficiencies are therefore most often found following periods of rapid new growth or during hot, dry periods.
Inside the plant, calcium moves to the cell wall where, along with boron and silicon, it plays a critical role in strengthening and ensuring cell integrity. Lack of calcium results in symptoms such as tip-burn in lettuce and brassicas, internal rust spot in potatoes and bitter pit in apples. Lack of calcium has also been linked to tendency to bruising and decreased storability in crops such as potatoes.
Supplementation of calcium is often desirable despite apparent adequacy of soil levels, due to lack of availability caused by lock up. If supplied directly to the soil, then it can be rendered immobile due to reaction with phosphates. This is particularly likely in potatoes, where water-soluble phosphate is applied as fertiliser.
Foliar application will provide calcium to the foliage, but the efficacy is very dependent on the product formulation and in any case it will not provide increased calcium to the tuber.
However, use of phosphite as a carrier can dramatically change this situation. Phosphites are highly systemic and rapidly absorbed by plant tissue, helping to deliver the partner cation quickly to where it is needed.
Foliar uptake will be enhanced by the addition of SW7¹.
Apply 2.5-5 l/ha, in a minimum of 200 l/ha water.
The spray tank should be filled with half the required water. If applicable, add the required amount of SW7 to the water before the Quad 14. After shaking the container, measure the required amount of Quad 14 and add to the tank whilst maintaining constant agitation. Add remaining water to correct dilution and spray.
Do not apply in tank mix with pesticides when crop is showing deficiency symptoms, is under stress, or in adverse weather conditions.
¹SW7 should be used to improve the wetting and spreading of the mixture. Use SW7 if it will be difficult to achieve good coverage, the leaves are waxy or tightly layered, or with dense crop canopies.