|Molina, Jae - UNIV. OF MINNESOTA|
|Allmaras, R - USDA-ARS RETIRED|
|Linden, D - USDA-ARS RETIRED|
Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: November 1, 2003
Publication Date: November 1, 2003
Citation: Dolan, M.S., Clapp, C.E., Molina, J., Allmaras, R.R., Linden, D.R., Baker, J.M. 2003. Soil organic carbon and nitrogen as a function of tillage, residue, and nitrogen management in minnesota. Agronomy Abstracts. Paper No. S03-dolan986431-Poster. Technical Abstract: Soil organic carbon (SOC) and nitrogen (N) are directly influenced by tillage, residue return and N fertilization management practices. Soil samples obtained from long-term field experiments, utilizing these various methods, provided an assessment of near-equilibrium SOC and N conditions. Treatments of conventional and conservation tillage, residue stover (returned or harvested), and two N fertilization rates were carried out at Rosemount, MN on a Waukegan silt loam (fine-silty over sandy or skeletal, mixed mesic Typic Hapludoll). The surface (0 to 0.05 m) soils with no-tillage had greater than 30% more SOC and N than moldboard plow and chisel plow tillage treatments. The trend was reversed at 0.20 to 0.25 m soil depths, where significantly more SOC and N were found in moldboard plow treatments (26 and 1.5 Mg SOC and N/ha-1) than with no-tillage (13 and 1.2 Mg SOC and N/ha-1), possibly due to buried residues resulting from the plowing action. Residue-returned generally resulted in more SOC and N than in plots where residue was harvested. Nitrogen fertilization generally did not influence SOC or N at most soil depths. These results have significant implications on management practices which maximize SOC storage and minimize potential N losses.