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Posted 27 August 2014. PMN Crop News.

Effective Phosphorus Management is a Continuous Issue

Source: SFP Press Release.

Leawood, Kansas (August 12, 2014)--For many farmers, proper management to help prevent the essential nutrient phosphorus (P) from getting locked-up in the soil is “an issue that just won’t go away,” says Dale Bartholomew, a certified crop adviser with GROWMARK FS, LLC in Caledonia, New York.


There are two very powerful reasons that farmers should manage P as closely as they normally manage nitrogen (N). One is economic, the other is environmental. “First, you can’t achieve top crop yields without efficient uptake of phosphorus by the plant,” Bartholomew explains. “Secondly, you want to minimize the amount of phosphorus left in the soil that would be subject to off-site movement into waterways.”

The key to meeting both of these objectives is to build a bigger root mass that efficiently mines phosphorus from the soil and ensures maximum plant uptake of the nutrient. “The challenge with phosphorus is that this nutrient carries a negative charge and quickly gets tied-up by binding with positively charged elements in the soil, such as calcium, magnesium, aluminum or iron, depending on soil pH,” the retailer says. “This binding process severely limits the amount of phosphorus that is available to be taken up by plants and put to good use in the growth process.”

To avoid this problem, Bartholomew recommends use of AVAIL® Phosphorus Fertilizer Enhancer to his customers. “Probably 30 to 40 percent of my customers are using this product,” he observes. “I have some customers who insist that AVAIL be used with phosphorus applications on every acre as part of a systematic program for proper nutrient management.”

Bartholomew cautions that AVAIL is not a “silver bullet,” but it does help manage and more effectively utilize the applied P that’s available for crop uptake. “We consistently see improved grain quality where AVAIL is used,” the CCA says. “I have one customer who continually has the highest test weights with his corn, soybeans and wheat, and he’s a big AVAIL user. These higher test weights help remove the worry of having a load of grain rejected at the elevator due to quality issues.”

Bartholomew says he has the best opportunity to work with his customers on using AVAIL when scouting fields after corn is at the four- or five-leaf stage. “When those plants are purple, we know it is due to phosphorus deficiency,” he adds. “AVAIL helps solve this problem, and in the process it helps those plants become more resistant to all kinds of environmental stresses.”

The retailer also warns his customers that high P levels in the soil, indicated by soil tests, don’t necessarily translate into the amount of P that is available for crop uptake. “This is a key consideration,” he emphasizes.

Since western New York’s rich farming region tends to have cold, wet soils, very little phosphorus is applied in the fall here. Instead, granular or liquid P is applied in the early spring in a band as a starter. “This starter treatment with phosphorus helps warm up the germination zone,” Bartholomew says. “The only fall P applications we make would be for winter wheat.”