Wheat straw and its biochar have contrasting effects on inorganic N retention and N2O production in a cultivated Black Chernozem

A laboratory incubation experiment was conducted to investigate the effects of direct incorporation of either wheat straw or its biochar into a cultivated Chernozem on gross N transformations calculated by the N-15 pool dilution technique and nitrous oxide (N2O) production rates. Incorporation of wheat straw stimulated gross NH (4) (+) (ammonium) and NO (3) (-) (nitrate) immobilization rates by 302 and 95.2 %, respectively, suppressed gross nitrification rates by 32.2 %, and increased N2O production by 37.7 %. In contrast, the addition of a biochar produced from the wheat straw did not influence any of the above N cycling processes. Therefore, application of biochar could be a possible management strategy for long-term C sequestration (through soil storage of stable C contained in the biochar) in soils without increasing N2O production rates, but could not effectively immobilize NO (3) (-) in the soil.