CAN WE ELIMINATE THE CALCIUM INTAKE SIMPLY BY WATERING?
It may seem to us, depending on the type of water with which we irrigate, that it can contain enough calcium and magnesium so as not to have to add fertilizers rich in these elements. What is true in that? Are we simply wasting money and over-fertilizing our crops?
We’ve always said it, calcium is a bloody hell . It is one of the macroelements (secondary macroelement) that gives more problems. Usually always due to deficiencies, even if we have a great calcium fertilizer plan. As we said in the article on calcium , its mobility is quite limited and it costs a lot to absorb it through the root system (damn Caspary Band…).
If we take a water analysis , as we have seen before, we will have a series of ions (cations and anions) that provide nutrients to the soil and, therefore, to the crop. Taking this into account and if we do things right, we can reduce the amount of fertilizer we add to the soil.
WHAT A WATER TEST CAN SHOW US ABOUT CALCIUM
If we take a typical water analysis, we will have different calcium (Ca ++) values, measured in ppm (parts per million) and milli-equivalents per liter. Some average values , according areas can be 7, 9 and up to 14 meq / L. Taking into account, and with the dose that we irrigate per hectare, that is a lot of calcium in the soil.
SO WHY DO WE APPLY CALCIUM TO THE SOIL?
Let’s see first, how many kg of calcium is applied, according to the Meq / L of this element in the irrigation water and the cubic meters with which it is irrigated.
Let’s see how much calcium is provided:
And now, how much magnesium is provided:
This, when we extrapolate it to the dose of water that a crop needs, there are many kilos and fertilizer units that are provided, just for watering.
Let’s look at quantitative values . A deficit irrigation program (deficit!) For citrus fruits, specifically lemon variety fine, needs, as a minimum, between 5,600 and 7,500 cubic meters per hectare. With a concentration of 9 meq / L of calcium (nothing unusual), we would be applying 1,000 to 1,400 kg of calcium to the soil.
Making numbers, with calcium nitrate , at a price of € 0.40 / standard kg, we would get between € 400 and € 560 per hectare and year out of our pocket. Not despicable, right?
And all this, the same with magnesium.
NOT ALL THE FOREST IS OREGANO WITH CALCIUM
When it seems we can get along with calcium, he goes and smacks us. Not everything is so beautiful and this rule is not always followed.
Although it is true that we are providing calcium and magnesium with irrigation water, this element is very sensitive to the presence of other elements, such as magnesium, and it always causes problems.
To carry out a correct fertilizer plan, whatever the crop, the ratio between calcium and magnesium (Ca / Mg) should be a minimum of 2 (ideally 5).
Therefore, as long as we irrigate with a Ca / Mg ratio of 2, we can almost completely replace the calcium intake. Then, yes, we will have to use some tricks to mobilize calcium even more (such as adding microelements, playing with the pH, etc.).
WITHOUT A CA / MG RATIO OF 2, WE’RE NOT GOING ANYWHERE
Getting this relationship in irrigation water is not so common. Sometimes calcium is well above this ratio of 2 compared to magnesium, which is good as long as it does not exceed 5. Other times the opposite happens, we have a Ca / Mg ratio of 1.5 or even less. Therefore, our rule is not met .
If all this were not enough, here are other causes that produce a calcium deficiency in the crop, even if there are adequate levels in the soil:
- High radiation and high photosynthetic rate.
- Water with high electrical conductivity (EC).
- High concentrations of ammonium ion (NH4) instead of nitrate (NO3).
- Low phosphorus content in soil.
Do you have blossom, peseta problems in your crops?