Elevated carbon dioxide and other green house gases have increased the earth temperature in recent decades, thus may be affecting biochemistry cycles in soils. An experiment was conducted in a completely randomized design with factorial arrangement in the laboratory conditions. Soil was treated with one percentage of cow manure compost and 200 kg /ha of Urea. Soil samples were exposed to two levels (25 and 35) temperature and two different carbon dioxide concentrations (350 and 700 ppm) for a 60 day period of incubation with three replications. The results showed that elevated carbon dioxide at 25 and 35 oC had a different effect on total dissolved nitrogen. Elevated carbon dioxide at 25 oC had no significant effect on total dissolved nitrogen (TDN) while at 35 oC TDN was increased. Temperature and CO2 had more effect on NO3+NO2 component of dissolved inorganic nitrogen rather than NH4. It seems that denitrification was higher in Elevated CO2 and high temperature treatments. Maximum and minimum rates of dissolved organic nitrogen (DON) occurred at 35 oC under elevated CO2 faster than other treatments. This study revealed that elevated CO2 along with temperature enhanced the nitrogen mineralization.

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