Fabian Fernandez, University of Illinois soil fertility scientist who worked on the study, says the bottom line is that shallow placement can work — in other words, allow faster application and less horsepower. But the shallow depth of injection could cause N loss and yield reduction when soil conditions are not near ideal for the application.

Fernandez says that if the soil is wet or too dry, there is a higher risk of N loss because anhydrous ammonia is being applied very close to the surface. Under such conditions, soil is less able to retain the anhydrous ammonia and some can be lost to the atmosphere, he says. The ideal soil condition for ammonia application is 15 to 20% moisture. 

“Farmers need to make sure soil conditions are optimum always, but especially when using HSLD applicators,” he adds. “Also, they need to make sure that the applicator is able to create a good seal once the nitrogen is applied. And, in preplant applications, it is best to try to separate the planting row from the point of anhydrous ammonia application to minimize the chance of seedling injury.”