Submitted to: USDA Symposium on Natural Resource Management to Offset Greenhouse Gas Emissions
Publication Type: Proceedings
Publication Acceptance Date: 7/15/2002
Publication Date: 11/19/2002
Citation: GOLLANY, H.T., CLAPP, C.E., MOLINA, J., LINDEN, D.R., ALLMARAS, R.R., LAYESE, M.F., DOWDY, R.H., CHENG, H.H. NITROGEN LEACHING AND DENITRIFICATION AS A FUNCTION OF RESIDUE MANAGEMENT AND NITROGEN FERTILZER RATES IN THE CONTINUOUS CORN SYSTEM. USDA SYMPOSIUM ON NATURAL RESOURCE MANAGEMENT TO OFFSET GREENHOUSE GAS EMISSIONS. 2002.
Technical Abstract: Maintaining crop production level with reductions in terrestrial greenhouse gases requires effective residue and fertilizer management. Our objectives were to: 1) quantify the effect of nitrogen (N) application rates on N losses; 2) examine the role of residue returned on N transformation and losses; and 3) verify the capability of the NCSWAP/NCSOIL model to simulate the dynamics of N and N^15 in the soil-plant system. A long-term continuous corn study was initiated on a silt loam soil in 1980 at Rosemount, MN. Conventional tillage plots with two levels of application rates (20 and 200 kg N/ha) and two types of residue management (residue removed, and residue returned) were used to calibrate the model. For the same amount of N15 added (0.8 kg N^15/ha), concentrations of N^15 in the corn and soil organic matter (SOM) were higher for the 20 than the 200 kg N/ha treatments. The model accurately predicted N^15 in the SOM at 0- to 15-cm depth for both fertilizer rates and residue management. The predicted cumulative N loss during 30-years simulation indicates more NO_3 leaching to below 1m-depth for residue removed than residue returned plots, while higher denitrification rates were predicted for the residue returned than residue removed.