北京平原地区造林树种对土壤肥力质量的影响

Effect of tree species on soil fertility quality in plain afforestation area,Beijing

土壤肥力影响林木的生长发育,反之林木的生长也会使土壤肥力发生变化。以北京市大兴区平原造林地区5种人工纯林(国槐、毛白杨、银杏、油松和榆树)为研究对象,测定林下0～20和20～40 cm土壤颗粒分形维数、有机质、全氮、全磷、全钾、有效磷和pH值,采用主成分分析法评价不同树种对土壤肥力质量的影响。结果表明:1)研究区土壤质地为砂壤土,土壤颗粒分形维数介于2. 439～2. 609,不同造林树种对其无显著影响。2)在0～20 cm,树种对土壤有机质、全氮、全磷和有效磷影响显著(P <0. 05);在20～40 cm,树种对土壤全氮、全钾和pH影响显著。随着土层加深,土壤有机质、全氮和全磷质量分数显著降低。总体来说,土壤全氮和全磷处于缺乏状态,有效磷较高,pH值偏高。3)在0～20 cm,土壤颗粒分形维数与土壤全氮呈极显著正相关(P <0. 01),与土壤有机质呈显著正相关;在20～40 cm,土壤pH值与全氮呈显著负相关,与全钾和有效磷呈显著正相关。4)通过主成分分析提取3个主成分,表明土壤颗粒分形维数、全氮和全钾对土壤肥力影响最大。综合得分为油松>国槐>银杏>毛白杨>榆树。认为,在北京大兴区进行平原造林应该根据造林目的进行树种选择,短期内提升土壤理化性质应该考虑种植国槐和油松等,同时应该进行传统肥料和有机肥的配合施用,以更好地改善土壤理化性质,为造林树种提供良好的生长环境。

[ Background ]Soil fertility affects tree growth and development, whereas tree growth also changes soil fertility. Exploring the relationship between tree species and soil nutrients will contribute to the structural adjustment of plantations and soil fertility restoration, and thus provide guidance on management and regulation of plain afforestation as well as soil ecological restoration.[ Methods ]Five kinds of pure plantations ( Sophora japonica , Populus tomentosa , Ginkgo biloba , Pinus tabuliformis , Ulmus pumila ) in the plain afforestation area, Daxing District, Beijing were selected for the determination of soil particle fractal dimension, organic matter, total nitrogen, total phosphorus, total potassium, available phosphorus and pH at depths of 0-20 and 20-40 cm. Principal component analysis was used to evaluate the effect of tree species on soil fertility quality.[ Results ](1) Soil texture of the study area was sandy loam, with soil particle fractal dimension in the range of 2.439 to 2.609, and there existed no significant differences between tree species.(2) At 0-20 cm, the effects of tree species on soil organic matter, total nitrogen, total phosphorus and available phosphorus were significantly different ( P <0.05). At 20-40 cm, tree species had significant effects on soil total nitrogen, total potassium and pH value. With the increase of soil depth, soil organic matter, total nitrogen and phosphorus decreased significantly. In general, total nitrogen and total phosphorus were in a state of deficiency, while available phosphorus mass fraction and pH value were high.(3) At 0-20 cm, soil particle fractal dimension had a very significant positive correlation ( P <0.01) with soil total nitrogen, and a significant positive correlation with soil organic matter ( P <0.05). At 20-40 cm, soil pH was significantly and negatively correlated with total nitrogen, but positively correlated with total potassium and available phosphorus.(4) Principal component analysis showed that soil particle fractal dimension, total nitrogen and total potassium had the greatest influence on soil fertility quality evaluation. The final comprehensive score was in the order of P. tabuliformis > S. japonica > G. biloba > P. tomentosa > Ulmus pumila .[ Conclusions ]Plain afforestation in Daxing District of Beijing should select tree species according to the purpose of afforestation and give priority to S. japonica and P. tabuliformis in order to improve soil physico-chemical properties in the short term. To better the effects, traditional fertilizer and organic fertilizer should be applied together so as to provide a good growth environment for the tree species.