We previously talked about how soil fertility is the foundation of all crop production. We also talked about how there are 16 essential elements that are needed by every plant to grow and reproduce, and how each element must be present within a concentration range for optimal plant growth.

During our 2016 soil testing program, we found sulfur (S), boron (B) and manganese (Mn) were particularly low in fields. Low S, B and Mn can have a detrimental effect on crops. Let’s take a look at the key plant functions of S, B and Mn:

Sulfur (secondary nutrient):

• Needed for the conversion of nitrate into organic nitrogen and for protein synthesis.

Boron (micronutrient):

• Needed for cell division (i.e. growth), cell wall synthesis and pollen germination.

Manganese (micronutrient):

• Important for photosynthesis, nitrate assimilation and iron metabolism.

Let’s take a deeper dive into how deficiencies of S, B and Mn affect corn and soybeans:

Sulfur:

• Corn: Stunted, spindly plants with light green color. Upper leaves show light green color. Interveinal yellowing or striping of leaves.
• Soybeans: New leaves remain pale yellow-green several days, then turn normal green.
• Conditions favoring deficiency: Acid and sandy soils that are low in organic matter. Wet and cool soils.

Boron:

• Corn: Light green-colored leaves. Slight yellowish stripe on upper leaves.
• Soybeans: Interveinal yellowing of upper leaves and stunting. Interveinal yellowing of whole plant.
• Conditions favoring deficiency: High soil pH and or organic matter. Depressed areas in fields. Organic sands, peats and mucks.

Manganese:

• Corn: Light green-colored leaves. Slight yellowish stripe on upper leaves.
• Soybeans: Interveinal yellowing of upper leaves and stunting. Interveinal yellowing of whole plant.
• Conditions favoring deficiency: High soil pH and or organic matter. Depressed areas in fields. Organic sands, peats and mucks.

Managing micronutrients is essential for optimal plant growth. Contact your local micronutrient supplier or your Syngenta representative for local recommendations for micronutrient product rates, application timings and recommended tank-mix products.

Submitted by Charles Scovill, CCA – Product Development Agronomist.

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