Magnesium – Critical for Each Growth Stage

Have you checked your Magnesium levels lately?

As seasons come and go, I’m always looking for ways to improve our productivity and profitability. Each year we look for issues or trend lines that we see across many acres, and try to tweak our recommendations and offer insights to enhance profitability. Over the past 3-5 years we’ve seen many growers running behind in their Potassium levels. And the reason was largely a side effect of a few years of high potash prices compounded with the fact that we had several record breaking corn yield years, and the soil reserves got drawn down.


The latest trend I see is… many soil tests show a less than desirable level of Magnesium. Why is that? I think we’ve done a good calling attention to the Potassium needs and building back the Potassium reserve, and we usually do a good job with Nitrogen. Many acres across the region also have access to manure, so Phosphorus levels are fairly easy to maintain. By default, Magnesium has become a forgotten element, or has just been overlooked.


Magnesium: Essential for Plant Growth and Development

Magnesium plays many roles in crop development, and is essential to the production of chlorophyll within the plant. It is also vital to the photosynthesis process within the plant, taking energy from the sun and helping to develop sugars and starches that feed the growing point within the plant. Magnesium also assists in carrying Phosphorus to all parts of the growing plant.


What Impacts Magnesium Availability in a Plant?

First, did you know that Magnesium is largely immobile in the soil in cooler soils? Soil temps below 55 degrees, reduce the availability of Magnesium. Did you ever hear cattlemen talk about grass tetany? Grass tetany comes from a lack of Magnesium in the spring when the grass is young and the ground is cool. The cool soils restrict the availability of Magnesium, which can then trigger grass tetany. What about your crops early in the spring? Particularly grass crops such as corn or cereal grains used for forages? Do they have enough available Magnesium to maximize productivity?


Second, what about your soil reserves? Do you have enough Magnesium to meet the needs of the crop you intend to grow?


Stunting of growth and pale-yellow stripes in the leaves with a purple leaf edge are symptoms of Magnesium deficiency.

Magnesium deficient corn stalk.

There is another part of the plant that often suffers unnoticed. Did you know that low Magnesium levels can impact root development? Yes, even when symptoms are unnoticed above ground, lower levels of Magnesium may be impacting the formation of roots underground, which may limit the overall nutrient availability to the crop.


Other elements can also interfere with the availability of Magnesium. Excessive Potassium levels can reduce the uptake of Magnesium. Low soil pH decreases the solubility and mobility of Magnesium in the soil, and drought conditions increase the risk of Magnesium deficiency.


What are the Best Sources of Magnesium

Magnesium is available from multiple sources. Here at PowerAG we have MagPower available, which is a chelated form of Magnesium in a liquid formulation, designed for foliar use. Other sources include dolomitic lime and various fertilizer blends. Sometimes your Calcium levels are already high and you need to source Magnesium from a non-calcium source.


We’re always interested in seeing you grow a good crop, so check your soil and tissue tests to make sure Magnesium is not holding back your yields. Always remember, it’s not just about one element in soil fertility, but the proper balance of each one. As always, here at PowerAG, we stand ready to assist you in any way we can.