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为了提高湿地松人工林养分利用效率,维持林地长期生产力,研究了湘北1667、2000、2400、3330、3900株·hm-25种不同密度11年生湿地松人工林营养元素含量、积累、分配、养分循环特征及其与密度的关系。结果表明:各器官营养元素含量差异较大,不同密度均遵循树叶>树枝>树干>树根>树皮的规律。单株营养元素积累量随林分密度的增大而减小。林分N、P、K、Ca、Mg 5种营养元素积累量为1542.3~2073.7 kg·hm-2,其中乔木层占70.3%~77.4%;林分吸收量、存留量和归还量分别为167.5~203.1、110.3~155.0和48.1~58.8 kg·hm-2·a-1,两个高密度林分的吸收量和存留量显著高于两个低密度林分,归还量随林分密度的增大而略微减小。林分及各元素的周转期总体上随林分密度的增大而加长,养分循环速率总体随密度的增加而降低,养分利用效率随林分密度的增大而增大。该研究结果为湘北湿地松林分密度调控、林下植被和凋落物管理等营林措施的制定提供了理论依据和实践指导。
In order to improve the nutrient use efficiency of Pinus elliottii plantation and maintain the long-term productivity of the plantation, the effects of 1667, 2000, 2400, 3330, 3900 plants · hm-25 kinds of 11-year-old Pinus elliottii plantations on the nutrient contents, accumulation, distribution, Cycle characteristics and its relationship with density. The results showed that the contents of nutrients in different organs were quite different, and the different densities followed the rules of leaves> tree branches> tree trunks> tree roots> bark. The nutrient accumulation per plant decreased with the increase of stand density. The accumulation of five nutrient elements of N, P, K, Ca and Mg was 1542.3-2073.7 kg · hm-2, among which the tree layer accounted for 70.3% -77.4%. The stand absorption, storage and return were respectively 167.5 ~ 203.1,110.3 ~ 155.0 and 48.1 ~ 58.8 kg · hm-2 · a-1, respectively. The uptake and storage of two high-density stands were significantly higher than those of two low-density stands, Large and slightly reduced. The rotation period of stands and the elements were generally longer with the increase of stand density. The nutrient cycle rate decreased with the increase of density, and the nutrient use efficiency increased with the increase of stand density. The results of this study provide theoretical basis and practical guidance for the establishment of silvicultural practices such as density control of understory wetlands pine forests, understory vegetation and litterfall management.