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United States Department of Agriculture

Agricultural Research Service

Title: Soil carbon and nitrogen sequestration as affected by long-term tillage, cropping system, and nitrogen fertilizer sources

Authors
item Sainju, Upendra
item Senwo, Zachary - ALABAMA A&M
item Nyakatawa, Ermson - ALABAMA A&M
item Tazisong, Irenus - ALABAMA A&M
item Redd, K Chandra - ALABAMA A&M

Submitted to: Agriculture Ecosystems and the Environment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 15, 2008
Publication Date: June 16, 2008
Repository URL: http://hdl.handle.net/10113/18876
Citation: Sainju, U.M., Senwo, Z., Nyakatawa, E., Tazisong, I., Redd, K. 2008. Soil carbon and nitrogen sequestration as affected by long-term tillage, cropping system, and nitrogen fertilizer sources. Agriculture Ecosystems and the Environment. 127:234-240.

Interpretive Summary: Carbon and nitrogen sequestration using novel soil and crop management practices are needed to increase soil C and N storage for C trading, offset greenhouse gas (CO2 and N2O) emission, reduce N leaching and N fertilization rates, and improve soil quality and productivity. Poultry litter, an inexpensive source of nutrients, is widely available in the southeastern USA because of a large-scale poultry industry. Disposal of large amount of poultry litter is causing an increasing environmental concern because of surface- and groundwater contamination of N and P from the litter through leaching and surface runoff. Poultry litter application along with conservation tillage and cover cropping can provide an opportunity to increase C and N sequestration and soil quality and productivity in the humid southeastern USA where SOM level is lower than in northern regions due to a long history of cultivation and rapid rate of mineralization. We evaluated the 10-year effects of tillage, cropping systems, and N sources on crop residue production and soil organic C and total N at the 0-20 cm depth in Decatur silt loam in northern Alabama, USA. Treatments were incomplete factorial combinations of three tillage practices [no-till, mulch till, and conventional till], 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). Rye was grown as winter cover crop and corn as residual crop without tillage and fertilization. Mean crop residue returned to the soil 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. Soil organic C and total N at the 0-20 cm depth were greater with poultry litter than with NH4NO3. These resulted in C sequestration rate of 510 kg C ha-1 year-1 and N sequestration rates of 41 to 49 kg N ha-1 year-1 with poultry litter compared with -120 to 147 kg C ha-1 year-1 and -23 to -3 kg N ha-1 year-1, respectively, with NH4NO3. Cropping and fertilization sequestered C at 730 kg C ha-1 year-1 and N at 67 kg N ha-1 year-1 compared with fallow and no-fertilization in NT. Long-term poultry litter application or continuous cropping can sequester C and N in the soil compared with inorganic N fertilization or fallow, regardless of tillage and cropping systems, thereby increasing soil productivity and reducing greenhouse gas emission. Instead of using it as a waste product, poultry litter should be used to increase C and N sequestration and improve soil quality.

Technical Abstract: Poultry litter application in no-tilled intensive cropping system could increase soil C and N sequestration compared with conventional management practices. We evaluated the 10-year effects of tillage, cropping systems, and N sources on crop residue (stems + leaves) production and soil organic C (SOC) and total N (STN) at the 0-20 cm depth in Decatur silt loam (clayey, kaolinitic, thermic, Typic Paleudults) in northern Alabama, USA. 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) in randomized complete block with three replications. Rye was grown as winter cover crop and corn as residual crop without tillage and fertilization. Mean crop residue returned to the soil 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. While SOC and STN concentrations at 10-20 cm after 10 year were not influenced by treatments, SOC and STN contents at 0-20 cm were greater with poultry litter than with NH4NO3 in NT and CT. These resulted in C sequestration rate of 510 kg C ha-1 year-1 and N sequestration rates of 41 to 49 kg N ha-1 year-1 with poultry litter compared with -120 to 147 kg C ha-1 year-1 and -23 to -3 kg N ha-1 year-1, respectively, with NH4NO3. Cropping and fertilization sequestered C at 730 kg C ha-1 year-1 and N at 67 kg N ha-1 year-1 compared with fallow and no-fertilization in NT. Long-term poultry litter application or continuous cropping can sequester C and N in the soil compared with inorganic N fertilization or fallow, thereby increasing soil productivity and reducing greenhouse gas emission.

Last Modified: 10/25/2014
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