[目的]探索氮素对樟子松幼苗生长发育的影响.[方法]采用完全随机分组设计,以高纯度的NH4NO3 作为试验用氮肥,添加量等级分别为 0 g/m2·a-1(CK)、20 g/m2·a-1(N1)、40 g/m2·a-1(N2)、80 g/m2·a-1(N3)共 4 个不同浓度的氮添加处理组,通过对比分析不同氮添加对樟子松幼苗根际土壤养分含量(有机质、速效氮、速效磷、速效钾等)、土壤酶活指标(碱性磷酸酶、过氧化氢酶、脲酶、蔗糖酶)、土壤净氮转化、N2O排放速率所产生的影响,分析不同氮添加对樟子松幼苗根际土壤的影响.[结果]N2 处理组对樟子松幼苗根际土壤养分含量、土壤酶活有明显的促进作用;N3 处理组对土壤净氮转化和N2O排放速率的促进作用最强,N2 处理组次之.[结论]考虑到实际生产的物料成本和人工成本,该研究认为以 40 g/m2·a-1 的NH4NO3 添加量是更为适宜樟子松幼苗培育的浓度.这对呼伦贝尔樟子松林区造林技术和实践发展具有一定的推动作用,为樟子松的苗圃培育幼苗、指导林地施肥习惯和樟子松林科学的人工抚育提供理论依据,可有效解决樟子松幼苗数量少、质量差等问题,加快樟子松人工林培育速度.
[Objective]To explore the effect of nitrogen on the growth and development of Pinus sylvestris var.mongolica seedlings.[Method]Using a completely randomized design,used high-purity NH4NO3 as the experimental nitrogen fertilizer.The addition levels were 0 g/m2·a-1(CK),20 g/m2·a-1(N1),40 g/m2·a-1(N2),80 g/m2·a-1(N3),altogether four nitrogen addition treatment groups with different concentrations,and the soil nutrient content(organic matter,available nitrogen,available phosphorus,available potassium,etc.)of P.sylvestris var.mongolica seedlings were compared and analyzed.The effects of soil enzyme activity indexes(alkaline phosphatase,catalase,urease,sucrase),soil net nitrogen conversion and N2O emission rate were analyzed.[Result]The N2 treatment group had a significant effect on soil nutrient content and soil enzyme activity in the rhizosphere of P.sylvestris var.mongolica seedlings.The N3 treatment group had the strongest effect on soil net nitrogen conversion and N2O emission rate,followed by the N2 treatment group.[Conclusion]Considering the actual material cost and labor cost of production,this study concluded that the addition of NH4NO3 at 40 g/m2·a-1 was a more suitable concentration for the cultivation of P.sylvestris var.mongolica seedlings.This research can contribute to the development of afforestation technology and practice in Hulunbuir Pinus sylvestris var.mongolica forest,and provide a theoretical basis for the nursery cultivation of P.sylvestris var.mongolica seedlings,guiding the fertilization habits of forest land and the artificial tending of P.sylvestris var.mongolica forest,which can effectively solve the problems of low quantity and poor quality of P.sylvestris var.mongolica seedlings and accelerate the cultivation speed of P.sylvestris var.mongolica plantations.