By Rick Koelsch, Livestock Environmental Engineer
The research team evaluated four N treatments, including poultry manure application rates of 150 lbs N/acre (PM150) and 300 lbs N/acre (PM300), urea ammonium nitrate (UAN) at 150 lbs N/acre (UAN150), and a control at 0 lbs N/acre (Control) on a tile-drained field near Ames, Iowa from 1998 to 2009. Manure and UAN were typically applied on the same day, typically between mid-April and mid-May. The research was conducted in loam soils with organic matter averaging 3.4% in the top 12 inches. Nitrate-N loss was measured from mid-March to October.Read more of this article to find out which treatments showed the least nitrate loss to water and which treatments offered the highest corn and soybean yields.