1. Ismail I., et al.,, Soil Sci. Soc. Am. J.58(193), ((1994))The Kentucky experiment accommodated four N rates (0 to 336 kg ha−1 year−1) and registered significant changes in soil C content (www.sciencemag.org/feature/data/1042216.shl).
2. Intergovernmental Panel on Climate Change Revised 1996 Guidelines for National Greenhouse Gas Inventories Reference Manual (Organization for Economic Cooperation and Development Washington DC 1996).
3. Bhat M. G., English B. B., Thurlow A. F., Nyangito H. O., Tech. Rep. ORNL/Sub/90-99732/2 (Oak Ridge National Laboratory, Oak Ridge, TN, 1994).
4. Izaurralde R. C. et al. Lal R. et al. Eds. Management of Carbon Sequestration in Soil (CRC Press Boca Raton FL 1998) p. 433 446.
5. The United States Department of Agriculture-Economic Research Service national average of N application on corn for the period 1982-1991 is 150 kg N ha −1 year −1 .