Calcium (Ca) – Understanding Minerals


Key Roles

Calcium is always the first mineral to correct in your soil, because it has so much impact upon other minerals. We often call calcium “the trucker of all minerals”, because it directly stimulates the uptake of seven other minerals. It also indirectly affects all mineral uptake, as it is the doorman at the cell membrane, through which all minerals move into the cell. In the soil, calcium serves to open up the soil. This allows the easy entry of all-important oxygen and the exit of CO2 for photosynthesis (gas exchange). Calcium effectively allows your soil to breathe.

In the plant, calcium governs cell strength and associated plant resilience. It also promotes cell division, growth and crop quality. In the absence of calcium you will see an increase in problems like blossom end rot in tomatoes and capsicums. However, poor cell strength will reduce resilience and there will be multiple associated issues.

Key Characteristics

Your Soil Therapy™ report presents calcium in terms of parts per million (ppm), and as a percentage of base saturation (reported in the table at the bottom of your test). The amount of calcium your soil requires is based upon the amount of clay (the medium for calcium storage) in your soil. We have computed the ideal calcium requirement, specific to your soil, in ppm, and as a percentage of base saturation.

Ideal Levels

There is no such thing as an ideal level of calcium for all soils. The appropriate amount of calcium for your soil is based upon the amount of clay available for storage. A light, sandy soil can store very little calcium, for example, but a heavy clay soil might have huge storage potential. You have what you have, so it is important to use a soil test service that will tell you the exact amount required to top up your unique fuel tank.

Refractometer Calcium (Ca) mineral in Soil Perth Western Australia

Key Considerations

It must always be remembered that too much calcium can sometimes be worse than too little calcium, as an excess can lock up the very same minerals that would otherwise be stimulated by this master mineral.

Calcium is the least mobile of all minerals, which means it is sluggishly delivered into the plant and poorly translocated into fruit. For this reason, there can be considerable benefits in foliar spraying chelated calcium to bypass this poor delivery problem.

High magnesium or potassium can reduce calcium uptake, and nitrogen excesses are similarly restrictive.

refractometer can be used as a guideline as to calcium availability in your crop. When you look through a refractometer, the colour demarcation on the vertical brix axis indicates the brix level, and should not be sharp and distinct. The goal becomes to ensure that this dividing line is indistinct and “fuzzy”. The more diffuse this line, the better your calcium levels.

To reiterate, calcium is the first thing to address in your soil, but you must understand exactly what amount is required. It is the “Goldilocks” mineral, which we should always strive to get “just right”.

Originally published, with thanks and permission, from Nutri-Tech Solutions.