Crop Nutrition

Record Crop Could Remove Large Amounts of Crop Nutrients

eKonomics News Team

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Looming record corn and soybean crops this fall stand to remove large amounts of nutrients, significantly impacting soil fertility levels.

Farmers have access to tools such as the eKonomics Nutrient Removal Calculator to estimate what rates may be needed to replace those nutrients and keep soil fertility at optimal levels for subsequent crops.

Large crops projected

Recently, the USDA projected the 2016 corn crop at a record 15.2 billion bushels, with a record average yield of 175.1 bushels per acre. This follows strong corn production and yields in 2015 and a previous record crop production and yield in 2014.

A number of states are projected to have significantly increased corn yields from last year. Illinois, Indiana, Missouri, North Carolina and Ohio are all forecasted to have double-digit yield increases compared to the 2015 corn crop.

For soybeans, the USDA projected a national record crop at 4.06 billion bushels with a projected record yield of 48.9 bushels per acre. If these records are realized, this would be the third year in row for record soybean production and yields nationwide. In fact, Indiana, Missouri and North Carolina are expected to have the largest yield increases from 2015.

Nutrient Removal

“It is important to know the amount of nutrients that are being removed,” says Scott Murrell, a director with the International Plant Nutrition Institute (IPNI).

According to him, replacing soil nutrients is good for long-term soil sustainability and soil health.

Dan Kaiser, Extension Nutrient Management Specialist at the University of Minnesota, agrees that replacing the removed nutrients will help farmers maintain their soil nutrient levels.

“It is a good place to start,” says Lloyd Murdock, soil specialist and professor at the University of Kentucky. “You are trying to get decently close to the amount of nutrients you need to apply to maintain levels.”

Replacing nutrients based on crop yields works in fields that previously tested at optimal levels. For soils testing below the critical levels, it’s vital to consider applying more than crop removal to reach yield potential.

Determining the amount of nutrients removed

If using the national average corn yield estimate with the eKonomics Nutrient Removal Calculator, approximately 123 pounds of nitrogen, 67 pounds of phosphate and 47 pounds of potash will be removed per acre.

For soybeans, 41 pounds of phosphate and 64 pounds of potash will be removed per acre.

Kaiser says farmers can also use long-term yield averages to estimate the amount of nutrients that are removed. If a farmer makes his fertilizer applications based on yields reported by the yield monitor, they should make sure it is properly calibrated.

Murrell says farmers should look at their crop yield and application records to help determine the amount of nutrients needed to be applied. However, he warns crops are known to remove more nutrients than expected.

Management practices, soil fertility, and different hybrids or varieties can cause the crop removal rates to vary.

“Getting a grain sample tested is a good way for a farmer to double check the amount of nutrients being removed,” Murrell says.

In addition, farmers that are harvesting stover could be removing more nutrients from the field as well. As a result, farmers should be aware of the amount of nutrients that will be removed and need to be replaced due to the potential record yields.