Iowa Department of Agriculture
Facebook Twitter Flickr
Regulation News and Events Marketing Conservation Animals
Site Search
Home
What We Do
Divisions
Bureaus
Programs
Secretary of Ag
Deputy Secretary
Forms & Licenses
Soil Conservation
Careers
Calendar
Regulations
Publications
Who to Contact
Boards-Commissions
Administrative Rules -IDALS
Administrative Rules -Soil

  Facebook Flickr Twitter You tube

 

For Immediate Release
Monday, October 31, 2016

 


 
 

Wait for Soil Temps to Remain Below 50 Degrees to Apply Anhydrous Ammonia

Waiting will prevent loss of fertilizer and help protect water quality
ARTICLE | FRI, 10/28/2016 - 13:43 | BY JOHN SAWYERDUSTIN VANDE HOEF

DES MOINES, Iowa – Farmers are reminded to wait until soil temperatures remain below 50 degrees Fahrenheit before applying anhydrous ammonia (NH3) fertilizer this fall. Soil temperatures have been slow to cool due to the unusually warm late October temperatures, and officials with the Iowa Department of Agriculture and Land Stewardship and Iowa State University Extension and Outreach said that waiting can help reduce nitrogen loss and better protects the environment.
“It is important that farmers wait for cooler soil temps to apply anhydrous so that there is a better chance the fertilizer stays put and will be available to the crop next spring,” said Bill Northey, Iowa Secretary of Agriculture. “Soil temperatures, like air temperatures, can change quickly so it is important that we wait with applications until soils are likely to remain below 50 degrees.”
ISU Extension and Outreach maintains a statewide real-time soil temperature data map on its website that agriculture retailers and farmers use to determine when fall N applications are appropriate. The website can be found at extension.agron.iastate.edu/NPKnowledge.

October 27 Iowa soil temperature map
The reason for waiting to apply anhydrous ammonia until soils are cold is that nitrification, the process of biological conversion of ammonium to nitrate, occurs at a more rapid rate with warm soils. Since ammonium-N does not leach and is not subject to denitrification, as is nitrate, it is more stable in the soil,” said John Sawyer, professor and extension specialist in soil fertility and nutrient management at Iowa State University.
In addition to waiting for soils to cool below 50 degrees, use of a nitrification inhibitor should be considered to help further slow conversion to nitrate.
Temperature is only one soil condition that farmers should consider when applying anhydrous ammonia. Making sure that the soil is not too dry, too hard or too wet, will reduce injection issues that allow ammonia to move to the soil surface and be lost to the air. If conditions are not suitable, then waiting for better conditions is suggested.
Farmers with questions about timing of fertilizer applications can talk to their local ISU Extension and Outreach field specialistor their ag retailer for more information.

https://www.extension.iastate.edu/article/wait-soil-temps-remain-below-50-degrees-apply-anhydrous-ammonia
 

About the Authors

John Sawyer
Agronomy
515-294-7078
jsawyer@iastate.edu

Dustin Vande Hoef
Iowa Department of Agriculture and Land Stewardship
515-281-3375
Dustin.VandeHoef@Ioawagriculture.gov

 

 
 
Mailing Address: IDALS,  Wallace State Office Building,   502 E. 9th Street,  Des Moines, IA 50319:     PH: 515-281-5321
  Sitemap   Privacy Statement   Relay Iowa State of Iowa Home
animals Conservation Marketing News and Events Regulations Cost Share