ARS | Publication request: Poultry Littler Application Increases Nitrogen Cycling Compared with Inorganic Nitrogen Fertilization

Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 20, 2010
Publication Date: March 22, 2010
Repository URL: http://hdl.handle.net/10113/43005
Citation: Sainju, U.M., Senwo, Z.N., Nyakatawa, E.Z., Tazisong, I.A., Reddy, C.K. 2010. Poultry Littler Application Increases Nitrogen Cycling Compared with Inorganic Nitrogen Fertilization. Agronomy Journal. 102: 917-925.

Interpretive Summary: Poultry litter, an inexpensive source of nutrients, is widely available in the southeastern USA because of a large-scale poultry industry. Disposal of large amounts of poultry litter is of increasing environmental concern because of groundwater contamination of N and P from the litter through leaching and surface runoff. Application of poultry litter to crops, however, can increase soil organic matter and nutrients that can increase yields and improve soil quality and productivity. Application of poultry litter along with conservation tillage and cover cropping can provide an opportunity to increase soil N storage and mineralization in the southeastern USA to reduce the need for N fertilization and improve soil, water, and air quality by reducing N leaching and N2O emission, a greenhouse gas responsible for global warming. The effect of long-term application of poultry litter and inorganic N fertilizer was evaluated on crop N uptake, soil N fractions, and N losses in conservation and conventional tillage with or without cover crop at the 0- to 20-cm depth in Decatur silt loam (clayey, kaolinitic, thermic, Typic Paleudults) in northern Alabama. Treatments were incomplete factorial combinations of three tillage practices [no-till (NT), mulch till (MT), and conventional till (CT)], two cropping systems (cotton-cotton-corn and rye/cotton-rye/cotton-corn), and two N fertilization sources and rates (0 and 100 kg N ha-1 from NH4NO3 and 100 and 200 kg N ha-1 from poultry litter). Nitrogen fractions were soil total N (STN), particulate organic N (PON), microbial biomass N (MBN), potential N mineralization (PNM), NH4-N, and NO3-N. Crop N uptake varied among treatments and years and total uptake from 1997 to 2005 was greater in rye/cotton-rye/cotton-corn than in cotton-cotton-corn and greater with NH4NO3 than with poultry litter at 100 kg N ha-1. After 10 yr, STN and PON contents at 0- to 20-cm were greater in NT with poultry litter than in other treatments, except in CT with poultry litter, resulting in a gain in N storage at 38 kg N ha-1 yr-1 with poultry litter compared with a loss at 4 kg N ha-1 yr-1 with NH4NO3. The MBN, PNM, and NO3-N contents were greater with poultry litter than with NH4NO3, regardless of tillage. Calculation of estimated N balance showed that poultry litter gained N at 191 to 556 kg N ha-1 compared to -75 to 201 kg N ha-1 with NH4NO3. Poultry litter application can increase soil N storage and mineralization and reduce the potential for N losses compared with inorganic N fertilization, thereby reducing the need for N fertilization and environmental N contamination. Poultry litter, instead of using it as a waste material, can be applied to crops for increasing soil quality and productivity and sustaining crop yields.

Technical Abstract: Poultry litter, an inexpensive source of nutrients and available in abundant amounts in the southeastern USA, may increase N cycling and reduce N losses compared with inorganic N fertilization if applied in crop production. We evaluated the effect of long-term application of poultry litter and inorganic N fertilizer on crop N uptake, soil N fractions, and N losses in conservation and conventional tillage with or without cover crop at the 0- to 20-cm depth in Decatur silt loam (clayey, kaolinitic, thermic, Typic Paleudults) in northern Alabama. Treatments were incomplete factorial combinations of three tillage practices [no-till (NT), mulch till (MT), and conventional till (CT)], two cropping systems [cotton (Gossypium hirsutum L.)-cotton-corn (Zea mays L.) and rye (Secale cereale L.)/cotton-rye/cotton-corn], and two N fertilization sources and rates (0 and 100 kg N ha-1 from NH4NO3 and 100 and 200 kg N ha-1 from poultry litter). Nitrogen fractions were soil total N (STN), particulate organic N (PON), microbial biomass N (MBN), potential N mineralization (PNM), NH4-N, and NO3-N. Crop N uptake varied among treatments and years and total uptake from 1997 to 2005 was greater in rye/cotton-rye/cotton-corn than in cotton-cotton-corn and greater with NH4NO3 than with poultry litter at 100 kg N ha-1. After 10 yr, STN and PON contents at 0- to 20-cm were greater in NT with poultry litter than in other treatments, except in CT with poultry litter, resulting in a gain in N storage at 38 kg N ha-1 yr-1 with poultry litter compared with a loss at 4 kg N ha-1 yr-1 with NH4NO3. The MBN, PNM, and NO3-N contents were greater with poultry litter than with NH4NO3, regardless of tillage. Calculation of estimated N balance showed that poultry litter gained N at 191 to 556 kg N ha-1 compared to -75 to 201 kg N ha-1 with NH4NO3. Poultry litter application can increase soil N storage and mineralization and reduce the potential for N losses compared with inorganic N fertilization, thereby reducing the need for N fertilization and environmental N contamination.