Spencer, IA: (Oct 17,2012) - Farmers are being encouraged to wait until soil temperatures cool to below 50 degrees Fahrenheit and remain there before applying anhydrous ammonia (NH3) fertilizer this fall.
Iowa Ag Secretary Bill Northey says, with the early conclusion to this year’s harvest, the temptation is there to go ahead with NH3 application.
But Northey says soil temperatures, like air temperatures, can change quickly, so he says it is important to wait until soils are likely to remain below 50 degrees.
Iowa State University Extension Climatologist Elwynn Taylor says that, historically, soil temperatures at a 4-inch depth cool below 50 degrees in the northern third of the state during the first week of November.
Northey adds that applicators should also pay special attention when applying NH3 in very dry soils. Dry soils can hold ammonia, but if it is not properly sealed, the ammonia can be lost.
Extension experts say that if following a round of application the ammonia can still be smelled, the applicator should make adjustments or wait for better conditions.