We learned a lot about Potassium and the role it plays in Corn Production when we wrote Understanding Potassium and it’s role in corn. This week we’re going to learn a little more about K (Potassium) and even add N to the equation! N of course stands for Nitrogen. Please tell us that you noticed our obvious use of KorN in the title – we worked so hard to get that in!

The scientists will tell us that the primary issue stems from dry soil conditions, which have hindered the development of crown roots, rather than a lack of nutrients in the soil. This cause-and-effect relationship reveals that inadequate moisture hampers root growth, leading to an insufficient uptake of nutrients by the plants.
In addition to dry soil conditions, there are six other common factors that contribute to potassium deficiency in corn:
- Cold soils
- Compacted soils
- Sidewall compaction
- Potassium stratification
- Root pruning
- Any factors that impede or limit root growth
After the V6 growth stage (around 4 to 6 weeks after planting), potassium uptake accelerates rapidly. Consequently, the effects of reduced uptake become more noticeable when the demand for potassium increases.

During this same period, it can be easy to mistake a potassium deficiency for a nitrogen deficiency. Both nutrients are mobile in the plant and migrate from older to newer plant parts, but their appearance on corn leaves differs.
To distinguish between these two issues, consider the following:
- A nitrogen deficiency starts at the leaf tip and progresses through the mid-rib, creating a V-pattern along the mid-rib.
- A potassium deficiency begins at the leaf tip and extends along the outer edges of the leaf. Additionally, symptoms of potassium deficiency first appear on the lower section of the corn plant. Older leaves may exhibit complete discoloration, wrinkling, curling, rolling along the edges, or premature death and shedding.
If you apply additional nitrogen when a potassium deficiency is present, it can exacerbate the potassium deficiency. If you suspect a potassium deficiency in corn, conduct tissue testing following your scouting to gain insights into the internal condition of the plants.
What? Explain that like I’m in third grade!
LOL! Challenge accepted! If your soil is already blessed with ample potassium levels, hallelujah! Your best bet is to pray for rain or summon the irrigation gods to work their magic and give those plants the nutrient boost they need. It’s like summoning rainclouds or getting a secret handshake with the irrigation system—whatever floats your farming boat!

But alas, once those plants fall behind in potassium uptake, it’s as challenging as trying to teach a sloth how to run a marathon. They just can’t seem to catch up later in the season, no matter how much motivational pep talk you give them. They’re the slowpokes of the plant world, forever lagging behind in the potassium race.
That’s why it’s crucial to be a proactive potassium manager, my friend. Take charge and apply potassium before planting, so those plants can have a continuous feast throughout the growing season. It’s like setting up an all-you-can-eat buffet for them, where potassium is the star of the show. Bon appétit, little plants!

Can you correct a Potassium Deficiency mid season?
Dealing with potassium deficiencies during the growing season can be quite the challenge. It’s like trying to find a unicorn in a haystack! If your soil already has enough potassium, your best bet is to cross your fingers and hope for some rain (or break out the trusty irrigation system) to give those plants a nutrient boost.

Once plants start falling behind in potassium uptake, it’s as hard as finding a needle in a haystack for them to catch up later in the season. They’ll be waving tiny white flags, begging for potassium but struggling to catch a break.
Now, let’s not get too reactive with our potassium solutions. It’s much wiser to plan ahead and apply it before planting so that the plants can feast on it throughout the growing season. We’ve heard some chatter about spraying potassium on the leaves, but hey, let’s not forget it still needs to go through the roots—those sneaky little nutrient gatekeepers.
Unless you’ve got some magical liquid or dry potassium that can be precisely applied right next to the plant roots, soil application during the season is usually a no-go. It’s like trying to hit a bullseye blindfolded—quite the challenge, my friend!

But fear not, potassium superheroes! Foliar-applied fertilizers with potassium might just save the day, depending on how severe the deficiency is and what caused it. If it’s a temporary issue caused by quirky soil conditions or a bit of moisture stress, those potassium-laden foliar products have a better chance of working their magic with a small but mighty dose of potassium.
So, hang in there, brave plant warriors, and don’t forget to sprinkle some humor along the way. After all, even potassium deficiencies can’t resist a good laugh!
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