Submitted to: Research Coordination Meeting
Publication Type: Popular Publication
Publication Acceptance Date: 11/23/2007
Publication Date: 11/23/2007
Citation: Sainju, U.M., Senwo, Z., Nyakatawa, E., Tazisong, I., Reddy, K.C. 2007. Soil Carbon and Nitrogen Pools as Influenced by Tillage, Cover Crop, Poultry Manure, and Nitrogen Fertilization. Alabama A&M University Collaboration Progress Report. p. 1-13. Interpretive Summary:
Technical Abstract: Quantification of soil C and N cycling as influenced by management practices is needed for C and N sequestration and soil quality and productivity improvement. We evaluated the 10-yr effects of tillage, cropping system, and N source on soil C and N fractions at 0- to 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 -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). Carbon and N fractions were soil organic C (SOC), soil total N (STN), particulate organic C and N (POC and PON), microbial biomass C and N (MBC and MBN), potential C and N mineralization (PCM and PNM) and NH4N and NO3-N. While concentrations of soil C and N fractions at 10 to 20 cm after 10 yr were not influenced by treatments, SOC and STN contents at 0 to 20 cm was greater with poultry litter than with NH4NO3 in NT and CT. This resulted in a C sequestration rate of 510 kg C ha-1 yr-1 with poultry litter compared with -120 to 147 kg C ha-1 yr-1 with NH4NO3 and N sequestration rate of 41 to 49 kg N ha-1 compared with poultry litter compared with -3 to -23 kg N ha-1 with NH4NO3. Poultry litter also increased PCM, MBC, PON, MBN, PNM, and NO3-N contents compared with NH4NO3. Cropping increased SOC, POC, PCM, STN, MBN, and PON contents compared with fallow in NT. Long-term poultry litter application or continuous cropping increased soil C and N storage, microbial biomass and activity, and N mineralization potential and availability compared with inorganic N fertilization or fallow, indicating that these management practices can be used to sequester C and N, offset atmospheric CO2 and N2O levels, improve soil quality and productivity, and reduce environmental degradation.