Submitted to: American Society of Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 8/15/2006
Publication Date: 11/12/2006
Citation: Zhang, Y., Clapp, C.E., Molina, J., Lee, D. 2006. Isotopic Nitrogen and Carbon Kinetics in Corn and Soil over 25 Years with Different Management Systems [abstract]. ASA-CSSA-SSSA Annual Meeting. ASA-CSSA-SSSA Annual Meeting. Nov. 12-16, 2006, Indianapolis, IN. 2006 CD ROM.
Technical Abstract: Soil N and C are two major components supporting plant growth and production. Managements (e.g. fertilization, residue return, tillage, and cultivation) heavily influence N and C cycling in agricultural soil system. Quantitatively documenting N and C dynamics in soil-water-plant system must be included at the long-term continuous field level in order to understand and mange the entire N and C cycles. The paper provides a unique set of continuous data from a 25-year field experiment located near Rosemount, MN. Field management involves tillage, residue and N treatments, including two tillage treatments (rototillage and no-till), two residue managements (residue removal and return) and 2 N treatments from 1980 to 2005, with 15N fertilizer added from 1980 until 1995. 15N fertilization provided a tracer to the applied N fertilizer to quantify N uptake by crops and N remaining in soil. Crop was grown for 15 years of corn (1980 to 1994) and for 4 years of soybean (1995 to 1998) prior to the recent 6 years of corn (1999 to 2005). No fertilizer N was added for soybean years. Changing crops established an in-situ label of soil organic carbon (SOC) based on the difference in the natural abundance 13C of C4 (corn) and C3 (soybean) plant.Our paper provides the unique field experimental data over 25-year period for modeling to simulate the dynamics of N, 15N, C, and 13C in the soil-plant system. It offers an advantage of verifying simulation models such as NCSWAP and of gaining insight about the processes that control soil N and C with crop production. Such long-term field information is of strategic significance and necessity in optimizing input and crop yield, decreasing soil N and C losses with reductions in terrestrial greenhouse gases, and improving soil and water quality.