江西千烟洲人工针叶林下狗脊蕨群落生物

A PRELIMINARY STUDY ON BIOMASS OF WOODWARDIA JAPONICA COMMUNITY UNDER A CONIFEROUS PLANTATION IN SUBTROPICAL CHINA

根据野外调查和实验分析研究了江西省千烟洲人工针叶林下狗脊蕨(Woodwardia japonica)群落的生物量、细根生物量、净初级生产力(Net primary productivity,NPP)、比叶面积(Specific leaf area,SLA)和叶面积指数(Leaf area index,LAI)等。通过叶片参数和地上生物量的相关关系建立了狗脊蕨单株地上生物量估算模型,分别为W1=0.021H1.545(R2=0.790)和W1=2.518(D2H)0.616(R2=0.894;H为株高,D为地径)。人工针叶林下灌草层地上生物量为367.8g.m-2(52～932g.m-2),凋落物为1631g.m-2(672～2763g.m-2),分别占乔木层地上生物量的4.7%(1.55%～13.2%)和20.7%(7.6%～32.1%)。狗脊蕨群落地上生物量和NPP分别为266.6g.m-2和88.67g.m-2.a-1,其中狗脊蕨种群占73.7%;地下生物量为212.6g.m-2。狗脊蕨的SLA和叶干物质含量(Leaves day mutter con-tent,LDMC)分别为144.0cm2.g-1和31.99%,二者之间呈显著负相关;最佳叶面积估算模型为S=21.9226-0.152L2+0.0009L3(9.0≤L(叶片长度)≤23.5;1.4≤W(叶片宽度)≤5.9)。狗脊蕨种群的LAI为1.8。土壤含水量对狗脊蕨生物量有显著影响。群落生物量与土壤有机质和全氮含量正相关。

Aims The purpose of the study was to determine the biomass （including fine roots）, NPP, specific leaf area （SLA）, leaf area index （LAI）, and soil nutrients of Woodwardia japonica community under artificial coniferous forest in Jiangxi Province in subtropical China. Methods Plants in quadrats were harvested and dry weight was measured. Leaf area was measured by scanning, and SLA was represented by the ratio of dry matter to leaf area. LAI of the population was estimated by SLA and leaf biomass. Important findings The relationships between aboveground b iomass （W1） and geometric parameters of W. japonica were established （ W1 = 0.021H^1.545（R^2 =0.790） and W1 =2.518（D^2H）^0.616（R^2 =0.894）, H： height; D： diameter）. The biomass of herbage and shmb under coniferous plantation was 367.8 g·m^-2（52-932 g·m^-2）, 4.7% of canopy layer. The accumulated litter under forest was 1 631 g·m^-2（672- 2 763 g·m^-2）. The above- and under-ground biomass of W. japonica community were 266.6 g·m^-2 and 212.6 g·m^-2, respectively. In total, the biomass of W. japonica population approximately accounted for 73.7% of the whole herbaceous layer. There was a significant negative-correlation between SLA and leaves dry matter content （LDMC）. A leaf area （S） model was established in the form of S = 21.922 6 - 0. 152L^2 ＋ 0.000 9 L^3（9.0≤L： max length of leaf ≤23.5;1.4 ≤ W： max width of leaf ≤〈5.9）.LM of W. japonica population was estimated as 1.8 m^2·m^-2. Soil water content affected biomass of the community. A positive correlation between biomass and soil nitrogen concentration or soil organic matter （SOC） was identified.