Farm Progress

Press release: Looking beyond the big three nutrients to find the necessary balance .

July 20, 2017

3 Min Read

This is a media release sent by manufacturers and other agriculture businesses gathered into one place.

Many growers across the country have experienced highly variable weather conditions in their fields this year. From standing water to drought conditions, it can be difficult to distinguish a crop nutrient deficiency compared to other weather-related stresses. Extreme weather patterns can often exaggerate nutrient deficiencies, or in many cases, a visual symptom may not be expressed by the crop. These seemingly unnoticeable reductions in plant growth and vigor are known as ³hidden hunger² and prevent the crop from attaining maximum yield.

Growers may notice their crops turning a shade of yellow or pale green, which could mean that the crops are suffering from a nitrogen (N) or a sulfur (S) deficiency. Visual deficiencies for a micronutrient like zinc (Zn) may exhibit white to yellow bands at the lower base of the leaf while the midrib and leaf margin remain green.

Curt Woolfolk, senior agronomist for The Mosaic Company, explains why it is so important to look beyond the "big three" ‹ nitrogen (N), phosphorus (P) and potassium (K) ‹ when scouting fields for visual nutrient deficiencies. Growers must also have a proper balance of secondary macronutrients and micronutrients in their soil.

"The availability of zinc to crops is directly related to soil pH; that is, higher pH levels limit zinc availability," says Woolfolk. "In addition to high pH and/or low-soil-test zinc, crops in early growth stages that are enduring cool, wet soils and cloudy weather may express zinc deficiency. This is why balanced crop nutrition from the start is critical to achieving a successful start and finish to the season."

In the field, visual symptoms of a sulfur deficiency and nitrogen deficiency are often easily confused. Symptoms of both deficiencies may appear as stunted plants, with a general yellowing of leaves. The best way to diagnose a deficiency is with a plant tissue analysis from a good and bad area of the field.

Applying total crop sulfur requirements in the sulfate form prior to planting increases the risk of sulfur leaching below the rooting zone and does not ensure a steady, season-long supply. Using a fertilizer that supplies S in both its readily available sulfate (SO42­) form and in a slowly released elemental sulfur (S0) form means that early season S needs are met along with gradual release of S from the elemental S, ensuring a season-long supply that matches crop demand.

Low commodity prices may tempt some growers to reduce or even eliminate applications of fertilizers like MicroEssentials SZ that contain secondary macronutrients and micronutrients. MicroEssentials provides season-long sulfur availability and uniform nutrient distribution to ensure the proper nutrient balance is available to your plants throughout the entire season in order to produce a higher yield. MicroEssentials provides a solid return on investment to help make those land and cash rent payments.

Both early and late-season scouting provide opportunities to identify visual nutrient deficiencies. Confirm the deficiency with tissue testing, mark the location, and record it as an area to be corrected prior to next year¹s planting. Areas of the Midwest have been experiencing both wet and dry conditions; in either case, now is an excellent time to be evaluating fields for nutrient problems.

Soil and tissue sampling on a field-by-field and within-field basis will allow you and your agronomic advisor to diagnose problem areas in your field, make the necessary corrections, and help you turn your land into peak-producing farm ground.

Determining the nutrient deficiencies in your soil and ensuring that you create a proper balance allows for better plant uptake, more efficient use of nutrients, and ultimately an optimum yield.

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