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How Plants Show Hunger

July 10, 2013 by Curt Woolfolk

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How Plants Show Hunger


The relationship between soil chemistry and nutrient uptake can fluctuate just as much as the weather from year to year. With today’s seed genetics, you may find some hybrids are great at optimizing a certain nutrient but wasteful with others. So it begs the question: For every pound of a nutrient applied, what did the plant really do with it? Am I providing proper crop nutrition?

That’s why it’s important to be able to identify a plant’s signs of hunger.

Looking closely at leaf tissues and stalk quality is a good place to start. They offer the first hints as to whether or not adequate nutrients are being supplied to the plant. The vibrancy of a leaf’s color is indicative of chlorophyll levels, so healthy leaves appear polished, rich and dark green in color.

Well-fed stalks have a clean, white pith area when cut away below the ear. But, in young plants with stalks that are hungry for N, stalks may appear a light yellowish-green in color. Frail, spindly stalks that are bare or unproductive can indicate P deficiency. Cut the stalk lengthwise to reveal if nodes appear dark brown inside the stalk; if so, K deficiency is likely to blame.

Visible signs of nitrogen deficiency in leaves include yellowing that begins at the tip of the leaf and moves down the midrib. Red or purple color hues in young plants indicates a phosphorus (P) deficiency, while firing and drying at the leaf edges of the lowest leaves indicates potassium (K) deficiency. Zinc (Zn) and boron (B) deficiencies also may have visual symptoms. Light-green or white stripes between leaf veins and parallel to the midrib may indicate zinc deficiency while extreme B deficiency can result in white-spotted leaves and barren stalks.

Deny a corn plant the proper amount of any one essential nutrient (macro or micro) and fail to spot telltale signs of hunger, and you’ve got a yield-robbing problem on your hands.

If you are interested in learning more about each nutrient and how it benefits plant health, or if you’d like to browse real photographs of different nutrient deficiencies in a variety of crops, click here and explore the Nutrient Knowledge section


Curt Woolfolk is a Product Development Specialist for The Mosaic Company. He leads the on-farm research and development program in North America, which includes testing Mosaic premium products, as well as new product concepts in pre-commercial stages.

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