Calcium is a vital component of cell walls and is involved in the metabolism
and formation of the cell nucleus. Calcium pectate in the cell walls provides
a physical barrier to disease entry. Calcium does not move readily within the
plant.
Calcium deficiencies may cause the growing point to die. It may
also cause the blossoms and buds to drop prematurely.
Calcium deficiencies
rarely occur in fruit crops grown on soils with a pH of 6.0-7.5. On coarse sandy
loam soil, with acidic or low pH, additional soil or foliar calcium may be required.
Refer to Table 3-15. Application Rates for Magnesium, Calcium and Micronutrients,
on this page. Calcium-related disorders may occur in some crops, for example tip
burn in strawberries, gummosis in plums, and bitter pit in some apple varieties.
Several management practices will reduce the occurrence of calcium-related
disorders. Avoiding over-application of nitrogen will help prevent excessive vegetative
growth which can dilute the calcium in the plant. Good soil management practices
ensure good root growth, which will promote both water and nutrient uptake. Timely
irrigation will help keep calcium moving into the plant.
Foliar applications
of calcium can be made to reduce the incidence of bitter pit in apples, gummosis
in European plums, stem and bunch breakdown in certain varieties of grapes and
various problems in pears. Only apply foliar calcium if a problem is anticipated
because of the potential for leaf burn and premature ripening.
For crop
specific details see:
To avoid adverse effects on fruit quality
and storability, do not apply calcium formulations containing nitrogen beyond
the end of July unless correcting a nitrogen deficiency. Consult OMAFRA Factsheet,
Bitter Pit Control in Apples,
Order No. 00-009.
Table 3-15a.
Application Rates for Calcium
(PDF 77 kb)
A number of micronutrients are available as chelates, with
various formulations and nutrient contents. Check the product labels for crop
specific recommendations. The effective use rate for chelated products is the
same as for other formulations.
Nutrient = Calcium (Ca)
| Source | % Nutrient |
Other nutrients | Soil Application |
Foliar Application |
|
calcitic limestone | 22-40% |
- | yes | no |
| dolomitic limestone |
16-22% | 6-13% magnesium | yes | no |
| calcium chloride | 36% | 64%
chloride | yes | yes |
| calcium nitrate | 19% | 15.5%
nitrogen | yes | yes |
| calcium sulphate (gypsum) | 23% | 19%
sulphur | yes | no |
| pelletized lime | 16-40% | 0-13%
magnesium | no | no |
Table
of Contents