Top Dress Micronutrients for Optimum Wheat Production


It is time to think about top dressing wheat, but not only with nitrogen. There are other nutrients, which can be very beneficial to crop production. Most soils of Eastern Washington are deficient in some of the micronutrients such as zinc, chloride, boron, sulfur, and copper to name some of the most frequently observed. Acid leaching can remove micronutrients from the soil, as can intensive cropping. Also, excessive use of phosphate fertilizers can diminish the availability of some micronutrients, particularly iron and zinc. Extremes in soil pH can result in reduced micronutrient availability.

Most plants have a pH range “sweet spot” in which the micronutrients in the soil are soluble enough to satisfy plant needs without becoming so soluble as to become toxic.

Chloride, sulfur, and boron are very mobile in the soil so it might make good sense to apply a foliar application. Plants absorb nutrients through their leaves and stems, using stomata—little openings similar to the pores of our skin.

Foliar sprays are well suited for micronutrient applications. Deficiencies identified during the growing season can be quickly corrected. It makes sense to have a comprehensive micronutrient plan in place to ensure that you are getting the best crop yields for your money and the extra effort invested. Remember — if you allow micronutrient deficiencies to become a limiting factor in crop development, further application of water, macronutrient fertilizers and other resources/time may give a limited return or be wasted.

“Prior to 10 years ago, we weren’t doing anything about micronutrients. Then we started doing more complete soil tests and testing plant tissue samples during the growing season. Now I wouldn’t consider planting a crop without checking micronutrients and addressing them. If you don’t have good micronutrient levels, you absolutely will restrict your yield potential.” says Brian Hefty from Ag PhD.

Pick blended micronutrient products for the crop and use what is needed each year keeping your micronutrients in balance in the soil. It will most likely keep your crop from being yield-limited from a lack of these minor nutrients.

Brian Hefty said, “Micronutrients can be applied pre-plant, at planting-time, as a foliar application, or we even streambar sometimes. There are lots of different ways to do it, just don’t forget about micronutrients.”

If you are thinking about foliar applications of micronutrients, contact your local providers or local Extension Office specialist for ideas and to develop a plan.