The 12 days of Crop Nutrients

Day 4 

Since I have already lost the theme of this thread (being a tie with the beloved carol, The 12 Days of Christmas), I won’t try to draw a connection between four calling birds and potassium – although I’m sure I could if I tried hard enough.

 

Potassium in one of the primary plant nutrients. It is essential for the transport of sugars and the formation of starches and oils. Potassium helps to regulate the opening and closing of a leaf’s stoma which are important for the efficient use of water by the crop.

Potassium deficiency in almonds
Apple with a potassium deficiency
Potassium deficiency in grapes

 

 

 

 

 

 

Potassium also promotes root growth, increases a plant’s resistance to disease and cold temperatures. It improves the size and quality of fruits, nuts and grains, and is essential in high-quality forage. Crops that produce large amounts of carbohydrates (sugars) require large amounts of potassium – sometimes even more th an nitrogen! Cotton, almonds, alfalfa, grapes, cherries, and peaches are all especially fond of potassium.

 

Common symptoms of potassium deficiency:

  • Slow growth
  • Tip and marginal leaf burning
  • Burning of older leaves
  • Weak stems and stalks causing lodging
  • Low fruit sugar content and shriveled seeds
Corn with a potassium deficiency

The 12 days of Crop Nutrients

Day 2

Welcome to our second day of the crop nutrients post. Hopefully you caught our first day – where we focused on phosphorus. In the traditional Christmas carol, the second day is two turtle doves. Since I don’t have any clever alliteration ideas for this one, I am going to talk about a secondary nutrient: calcium.

 

Calcium (Ca)

Calcium is a secondary plant nutrient that stimulates root and leaf development, activates several plant enzymes, and is required by nitrogen-fixing bacteria. In the soil, calcium indirectly influences yield by reducing soil acidity. It also helps improve root growth conditions, molybdenum availability, and uptake of other nutrients. In the soil, calcium indirectly influences yield by reducing soil acidity, which in turn lowers the solubility and toxicity of manganese, copper, and aluminum.

Alfalfa calcium deficiency comparison. (Left has deficiency, right does not)

Calcium is the third most important element in a plant. And, calcium is the fifth most abundant element on the planet. It makes sense that traditionally, growers don’t apply much calcium, because they assume the plant will get what they need from the soil. But, soil calcium is usually found in a form that is not easily taken up by plants.

 

Calcium deficiency in an apple

As an example, in an apple tree, the leaves, new shoots, and fruit all take calcium. The nutrient will be found in the tissues and the root, but the fruit cannot compete with the other parts of the plant. Hence why the fruit often doesn’t get enough calcium. That is why calcium deficiencies are evidenced on the fruit, rather than the rest of the tree. In apples, a calcium deficiency causes a disorder known as bitter pit. Bitter pit is a physiological breakdown of the cell walls in the fruit that occur below the skin of the fruit. For that reason, when scouting for calcium deficiencies in fruit trees, it is important to test the fruit, rather than relying solely on leaf or soil tests. Signs of calcium deficiency common in all crops include abnormal dark green foliage, premature shedding of blossoms and buds, and weakened stems.

 

Further problems with the calcium levels in the plant, and therefore in the fruit, are often caused by changes in the weather. In high temperature, low humidity conditions, for example, transpiration will increase dramatically, causing the plant to use more water. In irrigated crops, if watering has not been well scheduled, even soils with good levels of calcium can have problems in the fruit caused by calcium deficiency, such as blossom-end rot in tomatoes. This is the time when we need a fast calcium fertilizer that can be applied by foliar.

 

Common symptoms of calcium deficiency:

  • Death of growing points
  • Abnormal dark green foliage
    Example of calcium deficiency in lettuce
  • Premature shedding of blossoms and buds
  • Weakened stems
  • Tip burn of young leaves (primarily in vegetable crops)
    Calcium deficiency in corn
  • Water soaked, discolored areas on fruits
    Canola with a calcium deficiency

Calcium on Apples

Why is calcium important?

Calcium is the third most important element in a plant. And, calcium is the fifth most abundant element on the planet. It makes sense that traditionally, growers don’t apply much calcium, because they assume the plant will get what they need from the soil. But, calcium is usually found in a form that is not easily taken up by plants.

In an apple tree, the leaves, new shoots, and fruit all take calcium and the nutrient will be found in the tissues and the root, but, the fruit cannot compete with the other parts of the plant hence why the fruit often doesn’t get enough calcium. That is why calcium deficiencies are evidenced on the fruit, rather than the rest of the tree. In apples, a calcium deficiency causes a disorder known as bitter pit. Bitter pit is a physiological breakdown of the cell walls in the fruit that occur below the skin of the fruit. For that reason, when scouting for calcium deficiencies, it is important to test the fruit, rather than relying solely on leaf or soil tests.bitter pit in apples

In this particular trial, Horticulturists were testing for fruit firmness, how many apples produced on each tree, and how much the fruit weighs. At the North Central Research Station High-Density Apple Orchard, researchers test approximately 10 apples per experimental plot for firmness. They use a pentameter, which measures the pressure needed to break the cell part inside the apple. They test four spots on each apple, as research has shown there is a difference in firmness between the side of the apple exposed to sun, versus the shade-side. The average fruit firmness is reported.

A trial of the effects of LiberateCa™ in 2015 at the NCRS High-density Apple Orchard in Michigan showed that the apples treated with LiberateCa™ fall close to the preferred range of 14.5 lb – 17.5 lb for fruit firmness, while the untreated trees’ fruit firmness was significantly higher than desired. In addition, the treated trees had more apples per tree, and overall yield per tree increased as well. These trees were planted at 3 ½ feet between trees, 11 feet between rows, with a planting density of 1,100 trees per acre.Ca on apples

“If you can hang two more apples per tree, with 1,100 trees, you have 2,200 more apples – and that means more money in your pocket.” Horticulturist Jacob Emling