Refining the role of nitrogen mineralization in mycorrhizal nutrient syndromes

Abstract Forest stands dominated by ectomycorrhizal (ECM) associated trees often have more closed nitrogen (N) cycling than arbuscular mycorrhizal (AM) trees, with slower N mineralization in ECM thought to suppress inorganic cycling. However, most estimates of come from measurements net processes, which can lead an incomplete view ecosystem retention and loss. To explore the mechanisms driving syndromes, we measured gross production assimilation rates potential flux paired addition (from NH 4 SO NaNO 3 ) control plots within AM-dominated stands. We observed greater microbial ammonium compared AM stands, suggesting that increased demand drove lower found nitrification no effect on Therefore, low soil pH or high C:N ratios those not limited supply, may suppressed nitrification. Finally, denitrification nitrous oxide fluxes were addition, is controlled endogenous supply nitrate nitrification, exogenous inputs. Overall, conclude play a central role forming nutrient acidic conditions ultimately for