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Soil Fertility: The Basic Needs of the Plant

February 17, 2017

Soil fertility is the foundation of all crop production. A successful crop is largely dependent on management of vital crop nutrients and successful fertility program starts with good planning.

To start, it’s important to know that there are 16 essential elements that are needed by every plant to grow and reproduce. Each element must be present within a concentration range for optimal plant growth. If the concentration of an essential element in the root zone is too low, a nutrient deficiency occurs, which hurts plant growth.

Micronutrients boron (B), manganese (Mn), zinc (Zn), copper (Cu) and iron (Fe), and secondary nutrients calcium (Ca), magnesium (Mg) and sulfur (S) are just as important to plants as macronutrients nitrogen (N), phosphorous (P) and potassium (K). They differ only in the total amounts taken into the plant. Environmental stresses such as cool temperatures, extremely dry soils and water-logged soils can result in reduced uptake and leaching of certain nutrients (N, S and B).

In the spring of 2016, we collected soil samples from many of our research and agronomy plots across the U.S. and Canada, around the time of planting. This allowed us to see what our crops really had available at the start of the season. Knowing the nutrient availability at planting provides the opportunity to make a more informed decision on potential in-season fertility applications.

As a result of our soil testing program, we noticed that many fields would benefit from the addition of several micronutrients, particularly S (67% of soil samples rated as low), B (91% of samples rated as low to very low) and Mg (48% of samples rated as low), which should come as no surprise given the rainfall events of last spring and their inherent leaching characteristics. Remember, that nitrate-N, S and B can leach as much as 5 inches in a silty clay loam soil.

So, in planning for 2017, how do we maximize the yield potential of a grower’s field, knowing that we potentially have low to very low levels of S, B and Mg? The first step will be to conduct a soil test and/or an in-season tissue test. This could be the difference between making a profit or not.

Now is the time to make plans for addressing macro and micronutrient deficiencies, which can be easily corrected prior to planting, or with in-season applications. Plus, don’t forget to apply lime as need to adjust pH levels. Finally, be sure to check with your local supplier for tank-mix compatibility of micronutrient products with herbicide and fungicide applications.

Submitted by Charles Scovill CCA – Product Development Agronomist.

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