Nitrogen addition alters carbon and nitrogen dynamics during decay of different quality residues

摘要: Abstract With the increasing of anthropogenic nitrogen (N) deposition, understanding underlying mechanisms external N effect on residue decomposition is critical to improving our prediction ecosystem carbon (C) sequestration. An experiment decay subjected addition was conducted by 360 days incubation under laboratory condition, using leaf residues collected from Chinese fir (Cuninghamia lanceolata) (Cl) and eucalyptus (Eucalyptus urophylla) (Eu). Decay needle slower more limited than broadleaf Added significantly accelerated initial decay, then tended be negative. The switched time point coincided with C concentration peak, implying quality might affect impacts. More importantly, results, together previous studies multiple residues, illuminated that both positive negative effects became evident as low. We supposed this phenomenon attributed fact specific microbe (fungi, which possessed higher use efficiency bacteria) gradually exerted a dominant role in varying high low, shape would mediate For isotope signatures, supplied caused elevated 15N early stage, increased magnitude much greater for hardly-degradable (Cl). These dynamics patterns revealed enhanced microorganism activity added N, also probably confirmed microbe-mediated we presumed. Overall, research delivered very helpful implications nutrient management restoration heightened scenario future.