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根据广西区杉木(Cunninghamia lanceolata)、马尾松(Pinus massoniana Lamb)、桉树(eucalyptus)3种人工林分布情况,按其在各县市的分布权重选取不同龄级(幼龄林、中龄林、近熟林、成熟林、过熟林)典型样地,样地面积20m*50m,采用网格法采集表层土壤(0cm-10 cm),采用稀释平板涂抹法测定土壤微生物数量,氯仿熏蒸法测定土壤微生物生物量。结果表明:3种人工林各林龄阶段土壤可培养微生物中,细菌数量占有绝对优势,幼龄、中龄、过熟龄阶段微生物数量大小顺序为:杉木>桉树>马尾松,杉木幼龄、马尾松、桉树近熟林微生物数量在各自的林型中最大。微生物生物量碳(Cmi)c在杉木幼龄林、马尾松中龄林、桉树过熟林最大,微生物生物量氮(Nmi)c在杉木过熟林、马尾松和桉树幼龄林最大,微生物生物量磷(Pmi)c在杉木成熟林、马尾松幼龄林、桉树近熟林最大,杉木Cmic、Nmic、Pmic随着林龄的递增呈现出先降低后上升的趋势,马尾松和桉树微生物量随林龄的变化规律不明显。土壤Nmic与土壤细菌数量、真菌数量具有显著的(P<0.05)分形关系,其余的微生物量和微生物数量均不存在分形关系。
According to the distribution of three plantations of Cunninghamia lanceolata, Pinus massoniana Lamb and eucalyptus in Guangxi, the different age classes (young forest, middle age forest, Near-mature forest, mature forest, over-mature forest). The sample area was 20m * 50m, the surface soil (0cm-10cm) was collected by grid method, the soil microbial quantity was determined by dilution plate smear method, Soil microbial biomass. The results showed that the quantity of bacteria in soil cultivated microorganisms at each age stage of three kinds of plantations had an absolute advantage. The order of the number of microbes in young, mid-aged and over-aged stages was: Chinese fir> Eucalyptus> Masson pine, young Chinese fir, Pinus massoniana, Eucalyptus near-mature forest microbial population in the largest in the forest type. Microbial biomass carbon (Cmi) c was the largest in young Chinese fir, middle aged Pinus massoniana and over-mature eucalyptus. Microbial biomass nitrogen (Nmi) c was the largest in young Chinese fir, over-aged Pinus massoniana and Eucalyptus, Pmi c was the highest in mature Chinese fir plantations, young stands of P. massoniana and near eucalyptus mature forests. Cmic, Nmic and Pmic of Chinese fir showed the trend of first decreasing and then increasing along with the increasing of forest age. The biomass of Pinus massoniana and Eucalyptus The change of forest age is not obvious. There was a significant (P <0.05) fractal relationship between soil Nmic and the number of soil bacteria and fungi in soil, and no correlation existed between the remaining microbial biomass and microbial population.