改变碳源输入对针阔叶混交林土壤氮矿化的影响

Effects of controlling carbon input on nitrogen mineralization in soils of broadleaved-needle mixed forest plantation

为了解不同碳输入对混交林土壤中有效氮含量及氮矿化速率的影响,采用树脂芯原位测定法对马尾松+樟树混交林不同处理(添加凋落物、去除凋落物、去根、去根添加凋落物、去根去除凋落物)下的土壤氮矿化进行研究。结果表明:5种处理下土壤累计净氮矿化量为添加凋落物(12.10 mg/kg)>去根添加凋落物(6.03 mg/kg)>去根(0.96 mg/kg)>去除凋落物(-0.46 mg/kg)>去根去除凋落(-0.63 mg/kg);NH4+-N、NO3--N含量在培养前后均发生了显著变化;培养后,NH4+-N含量在添加凋落物、去除凋落物、去根、去根去除凋落物4种处理之间差异显著(P<0.05);各处理之间NO3--N含量差异显著(P<0.05)。研究结果为揭示亚热带森林生态系统氮循环机理提供科学依据。

In order to understand the available nitrogen content and nitrogen mineralization rates under different carbon inputs in the soils of mixed forest, the nitrogen mineralization in the soils of mixed forest of Pinus massoniana and Cinnamomum camphora was measured under different treatments （extra litter addition with root （LAR）, litter removal with root （LRR）, control without root （CNR）, extra litter addition without root （LANR）, litter removal without root （LRNR） by using a resin-core technique. The results show that after incubation the contents of NH4＋-N and NO3--N were significantly changed. The differences in content of NH4＋-N were found under 4 different treatments （LAR, LRR, CNR, LRNR）. The significant differences were found in content of NO3--N. Under 5 different conditions （CR, LAR, LRR, CNR, LANR, LRNR）, the net nitrogen mineralization contents of 5 different treatment were extra litter addition with root （12.10 mg/kg）〉extra litter addition without root （6.03 mg/kg）〉control without root （0.96 mg/kg）〉litter removal with root （-0.46 mg/kg）〉litter removal without root （-0.63 mg/kg）. The researching results provide a scientific method for revealing circulation mechanism of nitrogen in subtropical forest ecological system.