Under warm breezy conditions, much of the ammonia is lost in a matter of hours. Figure 2 shows losses under two different weather conditions. Nearly 80 percent of the ammonia was lost under warm conditions. The greatest loss occurs in the first 24 hours, more occurs in the second 24 hours, and losses continue slowly after that. Surface condition of the ground also affects nitrogen losses.
More nitrogen is lost from crop residue than tilled soil.
Soil is negatively charged, so it will prevent losses as compared to crop residue. By combining the percent ammonia with the crop residue cover, a chart of overall losses can be shown for normal weather conditions, Figure 3. Time is the critical factor that can be controlled. Losses occur only when manure is broadcast on the surface and left there. Losses can be eliminated by injecting or incorporating manure immediately.