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 ¹⁵N 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.