Webinar: Managing Fall Fertilization

Fall fertilization offers several benefits, including lightening the workload throughout the year and ensuring nutrients are available in the spring. It also helps growers manage time, crop nutrients and, ultimately, the bottom line.

The use of best management practices and fertilizer-efficiency products can produce savings by protecting applied fertilizer from losses. This was the subject of CropLife Media Group’s Webinar “Managing Fall Fertilization,” presented by Gary Tuxhorn, agronomy technical services manager, United Suppliers Inc., and Jake Sanders, Specialty Fertilizer Products’ (SFP) vice president of market development.

Soil Testing

During the Webinar, Tuxhorn discussed crop response curves, application methods and soil testing and interpreting results.

There are two basic levels of the crop response curve, he said. “In the first level, there are visible deficiency symptoms,” Tuxhorn said. “For example, if there’s a phosphorus deficiency, you’d see a shortening of the internodes. For nitrogen or sulfur deficiencies, you’d see a yellowing of the plant.”

The other level within the crop response curve is what Tuxhorn called “Hidden Hunger.” “You don’t have obvious visual deficiency symptoms, but you’re also not getting the yields you’d like to see,” he said.

The crop response curve is typically divided into five soil test zones: Very Low, Low, Optimum, High, Very High. “We can use these five zones to guide us to how much fertilizer to apply,” he said.

Tuxhorn said there have been four basic methods of applying fertilizer over the years. They are:
Mining. Mining the soil means applying less fertilizer than what is being taken out with the crop.
Build. With the build method, the amount of fertilizer being applied is adjusted depending on the soil test category.
Maintenance. One of the older fertilizer application methods, maintenance programs require whatever fertilizer the crop removes, the same amount is re-applied regardless of soil test category.
Sufficiency. The sufficiency method varies according to optimal economic return during the year of application. “Nitrogen (N) has been applied using this way for a long time,” Tuxhorn said. “A lot of universities are now recommending a sufficiency approach with phosphorus and potassium.”

Interpreting soil test categories can be challenging, Tuxhorn said. “Soil testing can vary lab to lab and state to state,” he said. “You must make sure the soil extract is the one that is calibrated for the response curve that you’re looking at. Also, be careful that you are explaining soil tests to growers as they apply to their farm.”

Phosphorus Management

Soil chemistry is more complex with phosphorus (P) than it is with other nutrients, Tuxhorn explained.

“After application, P reacts with soil cations and ‘converts’ to much less soluble forms,” he said. “Crop recovery is limited to 5% to 25% of applied P fertilizer during the season of application. That’s in contrast to N where we’d typically see 40% to 60% get into the crop.”

Several practices for managing P fixation have been used over the years, Tuxhorn said, including applying extra P, banding P, banding P with anhydrous ammonia and banding with humic acids. But one of the most recent crop management tools for improving P uptake is AVAIL.

“University research shows that 75% to 95% of P gets tied up in the soil,” SFP’s Sanders said. “This means the farmer is spending money and yet the product is not getting into the plant.”

This happens because P has a negative charge on it just like a magnet, and it comes together with other elements in the soil that are positively charged, Sanders explained. These elements tie up that P and leave it unavailable to the crop that year.

Introduced by SFP, AVAIL P fertilizer enhancer is a water-soluble polymer with a very high negative charge, Sanders said. When that polymer is used as a coating on granular P or mixed into fluid P fertilizers, it diffuses out in the soil and interfaces with those positive charges that would typically tie up the P.

“So we can hold those positives in that AVAIL polymer for about 10 to 12 months, and that’s going to give a good season of P availability,” he said.

Leave a Reply

Latest News
RoGator RG1300B AGCO
EquipmentAGCO Opens Nominations for 12th Annual Operator of the …
August 18, 2017
AGCO Corp. has announced the opening of nominations for AGCO Application Equipment’s 12th Annual Operator of the Year. The award Read More
ManagementTravels, Mergers, and CropLife 100 Updates
August 18, 2017
Editors Paul Schrimpf and Eric Sfiligoj discuss recent trips they’ve taken, the latest news on market consolidation, and the 2017 Read More
Corn Seed
Seed/BiotechSeed Innovations Benefit All of the Seed Industry
August 17, 2017
Innovations from throughout the seed industry help address many of the economic, environmental and health issues we face as a Read More
SpreadersGVM to Introduce New Prowler at MAGIE
August 17, 2017
The newest Prowler in GVM’s line-up will be introduced next week at the Midwest Ag Industries Expo (MAGIE), August 23 Read More
AcreEdge bag
Seed/BiotechLandus Cooperative’s AcreEdge Seed Brand Gears Up for 2…
August 17, 2017
Growers in more than 26 Iowa and Minnesota counties are seeing field signs with a new brand name at end Read More
Engenia soybeans
ManagementCorn and Soybean Yield Forecasts Larger than Expected
August 17, 2017
The USDA’s August Crop Production report contained larger-than-expected forecasts for the 2017 U.S. corn and soybean crops. At 169.5 bushels Read More
ManagementU.S. Ag Secretary Introduces SCORE
August 17, 2017
U.S. Agriculture Secretary Sonny Perdue signed a new agreement to support new and beginning farmers. On August 5, Perdue joined Read More
CHS-FFA-Minnesota
CropLife 100CHS and FFA: A Homerun Partnership
August 17, 2017
CHS hosted the Minnesota FFA for its annual FFA night at CHS Field. FFA students, educators and CHS leadership enjoyed Read More
Greg Musson, Gar Tootelian
CropLife 100Gar Tootelian Foundation Donates Half Million Dollars t…
August 16, 2017
Students at Immanuel Elementary are looking forward to the first day of school for two reasons this year. One, they Read More
Water Drainage
StewardshipNew System Could Remove Two Water Pollutants from Ag Fi…
August 14, 2017
Algae blooms in the Gulf of Mexico use up the majority of the oxygen in the water, leading to massive Read More
Eric SfiligojThe Top 10 Crop Protection Companies, Post-Mega Mergers
August 14, 2017
Everyone loves a good Top 10 list. In fact, some prominent celebrities such as David Letterman spent much of their Read More
ManagementThe DuPont-Granular Deal, Dicamba Update, and Upcoming …
August 11, 2017
Matthew Grassi joins Paul Schrimpf for the second week in a row to talk about DuPont’s acquisition of Granular, as Read More
Soybeans weeds
HerbicidesOngoing Evaluation Key to Controlling Weeds, Improving …
August 10, 2017
As the sun bears down on record U.S. soybean acres this August, farmers keep their eyes on their fields to Read More
Young Corn Plants
Seed/BiotechMycogen Seeds Offers Novel Product to Battle Pythium, O…
August 10, 2017
After a season plagued by seedling diseases caused by cool, wet soils at planting, farmers have a new option to Read More
Corn Field
FertilizerProtect Applied Manure Straight From the Manure Pit to …
August 10, 2017
Farmers who use liquid manure to fertilize corn crops can now mix Instinct nitrogen stabilizer in their pit for easy Read More
Iowa waterways
Stewardship2,600 Iowa Farmers Commit $8.7 Million to Water Quality…
August 9, 2017
Iowa Secretary of Agriculture Bill Northey announced Tuesday that a record number of Iowa farmers signed up to install nutrient Read More
Natives-First-Purple_Prairie_Clover
Seed/BiotechLa Crosse Seed Continues Focus on Soil and Water Conser…
August 9, 2017
La Crosse Seed is doing its part to lead communication to ag retailers across the country on the importance of Read More
HerbicidesAg Secretary Perdue Comments on Dicamba Issue
August 9, 2017
Agriculture Secretary Sonny Perdue indicated to reporters this week that he would like to see the industry work out a Read More