大兴安岭火后不同恢复方式森林细根-土壤C、N、P化学计量特征OA

To explore the effects of restoration patterns on stoichiometric characteristics of arbor fine roots and soil after fire dis-turbance,we selected three forest types in severely burned areas of the Greater Khingan Mountains as research objects,in-cluding naturally restored secondary Betula platyphylla forest,artificially planted Larix gmelinii forest,and unburned pri-mary L.gmelinii forest.The mass fractions of carbon(C),nitrogen(N)and phosphorus(P),stoichiometric ratios and their correlations in arbor fine roots and soil were analyzed.The results showed that:(1)There were significant differ-ences in total C,total N and total P mass fractions of fine roots among the three forest stands,with the secondary B.platyphylla forest having the highest total carbon and total nitrogen content.The N∶P ratios of fine roots in all three forests were lower than 14,indicating that their growth was restricted by nitrogen.(2)The mass fractions of soil total C,total N and total P in primary L.gmelinii forest were significantly higher than those in the other two forests(P<0.05).The soil C∶N ratios of all forest stands were higher than the national average level,while soil N∶P ratios were relatively lower.(3)Fine root stoichiometric characteristics were closely correlated with soil stoichiometry,yet the correlation patterns var-ied among forest types.The fine root N∶P ratio changed synchronously with soil N∶P ratio in secondary B.platyphylla forest,while fine root C∶P ratios were significantly correlated with soil N∶P ratios in the two L.gmelinii forests.(4)Overall,the secondary B.platyphylla forest had the lowest C∶N ratio and higher fine root turnover rate,the artificial L.gmelinii forest presented low nitrogen cycling efficiency,the primary L.gmelinii forest possessed higher soil total C con-tent,soil C∶N ratio and fine root C∶N ratio,reflecting its low nutrient turnover rate and slow organic matter decomposi-tion rate.