Title: Fall- and spring-applied poultry litter effectiveness as corn fertilizer in the mid-southern United States Authors
Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 15, 2013
Publication Date: N/A
Interpretive Summary: Applying poultry litter and other manures in the fall has been shown to be an effective practice in regions that experience freezing fall and winter temperatures, but whether this holds true in the warmer southern and southeastern US has not been well researched. We conducted a 3-year field research in northern Mississippi to determine the effectiveness of poultry litter as corn fertilizer when applied in the fall. The results showed that the value of poultry litter is reduced by 12 to 15% if applied in the fall, relative to that applied in the spring. Corn fertilized with 8 tons/acre raw poultry litter applied in the fall produced 12.8% less grain and 15.0% less biomass than corn fertilized with the same amount of litter applied in the spring. The results also showed that nitrogen from spring-applied litter is not as plant-available as commonly assumed. Commonly, about 50 to 65% of the total nitrogen applied with poultry litter is considered usable by corn plants in the first year. In our research, we found the nitrogen availability not to exceed 35% of the total applied in the spring. Overall, our research shows that applying poultry litter in the fall to fertile spring-planted crops may not be advisable in regions with warm fall and winter months similar to that of northern Mississippi.
Technical Abstract: The effectiveness of fall- or winter-applied poultry litter, relative to spring-applied litter, as row crop fertilizer in the southern and southeastern US has not been well researched. A 3-yr field research was conducted in northern Mississippi to determine the effectiveness of litter as corn fertilizer and quantify loss of its potency when applied in the fall. The grain yield and biomass of corn that received fall-applied 9 Mg ha-1 poultry litter, 18 Mg ha-1 poultry litter, or 202 kg ha-1 inorganic N as NH4NO3 was compared against that of corn that received the same fertilization treatments applied in the spring including an unfertilized control. Corn fertilized with 18 Mg ha-1 litter in the spring produced 24% less grain yield in the first year but up to 21% more grain yield in the last 2 yr than corn fertilized with NH4NO3 in the spring. The results suggest that spring-applied litter N is not as available in the first year of application as the commonly assumed 50 to 65%, but a fraction of what is not available in the first year is carried over to subsequent years. We estimated only 31% at the 18 Mg ha-1 and 46% at the 9 Mg ha-1 N availability in the first year. Applying 18 Mg ha-1 litter in the fall, relative to spring application, reduced grain yield by 12.8% and biomass by 15.0% when averaged across the 3 yr. These results quantify the consequences of applying poultry litter in the fall in regions with warm fall and winter months similar to that of northern Mississippi.