大兴安岭多年冻土区泥炭地土壤性质与微生物呼吸活性研究

Soil Property and Microbial Respiration Activity of Peatland in Permafrost Region in Greater Hinggan Mountains

以大兴安岭北部黑龙江省漠河市图强林业局多年冻土区的一块泥炭地作为采样地,2012年9月3日,采集腐殖质层和0~40 cm深度土层(以10 cm厚度为一层)的样品,分析腐殖质层和土壤样品的基础理化指标、生态化学计量、养分元素和微生物呼吸活性特征。研究结果表明,随着土壤深度的增加,0~40 cm深度土壤的有机碳、全氮和全磷含量都在减小,其粗灰分含量、pH、容重和钠元素含量都在增大,其镁和钾元素含量波动增大,其钙元素含量波动减小;泥炭地30~40 cm深度的粘土层的有机碳、全氮和全磷含量都显著小于腐殖质层和0~30 cm深度的泥炭层(p<0.05),其粗灰分含量、pH、容重、钠元素含量、镁元素含量和钾元素含量都显著大于腐殖质层和0~30 cm深度的泥炭层(p<0.05),其钙元素含量显著小于腐殖质层和0~20 cm深度的泥炭层(p<0.05);随着土壤深度的增加,0~30 cm深度泥炭层的碳氮比、碳磷比和氮磷比都在增大,碳钠比和碳钙比都在减小,碳镁比和碳钾比都呈单峰型变化;泥炭地腐殖质层的碳氮比、碳磷比和碳钠比都显著大于0~40 cm深度土壤(p<0.05);而30~40 cm深度的粘土层的碳氮比、碳磷比、碳钠比、碳镁比、碳钾比和碳钙比都显著小于腐殖质层和0~30 cm深度泥炭层(p<0.05);泥炭地0~40 cm深度土壤中的镁含量分别与钾含量、钙含量显著正相关(n=15,p<0.01),钾含量与钙含量显著负相关(n=15,p<0.01),表明泥炭地土壤中的养分元素的来源各异;泥炭地土壤中营养元素含量相对较大和它们之间具有相关关系可能与其在历史上受到火灾干扰有关;大兴安岭北部多年冻土区泥炭地土壤中的微生物活性指标值相对较小,腐殖质层的微生物量碳含量和基础呼吸强度都最大,随着土壤深度的增加,土壤的微生物量碳含量和基础呼吸强度在不断减小,但是,土壤微生物对有机碳的利用率较大,微生物活性所需要的能量较高。

A peatland in permafrost region of the north of Greater Hinggan Mountains(Tuqiang Forestry Bureau in Mohe city, Heilongjiang province) were chosen as the study area. The samples of the humus layer and soil layers(every 10 cm layer) at 0-40 cm depth were collected on September 3, 2012. The basic physical and chemical properties, stoichiometry, nutrient elements, and microbial respiration activities of the samples were analyzed. The results showed that with the increase of soil depth, the contents of total organic carbon,total nitrogen, and total phosphorus decreased, the contents of crude ash, pH, bulk density, and sodium increased, while the fluctuation of magnesium and potassium contents were higher and the fluctuation of calcium content was lower. The contents of total organic carbon, total nitrogen, and total phosphorus of 30-40 cm clay layer were significantly lower than those in the humus layer and peat layers at 0-30 cm depth(p<0.05). The contents of crude ash, pH, bulk density, sodium, magnesium, and potassium were significantly higher than those in the humus layer and peat layers at 0-30 cm depth(p<0.05). The contents of calcium were significantly lower than those in the humus layer and peat layers at 0-20 cm depth(p<0.05). With the increase of soil depth, the ratios of C/N, C/P, and N/P of peat layers at 0-30 cm depth increased, the ratios of C/Na and C/Ca decreased, and the ratios of C/Mg and C/K showed single-peak changes. The ratios of C/N, C/P,and C/Na in humus layer of peatland were significantly higher than those in the soils at 0-40 cm depth(p<0.05). The ratios of C/N, C/P, C/Na, C/Mg, C/K, and C/Ca of clay layer at 30-40 cm depth were significantly lower than those of humus layer and peat layers at 0-30 cm depth(p<0.05). There was a significant positive correlation between the content of magnesium and the content of potassium and calcium in the soils at 0-40 cm depth(n=15, p<0.01), and a significant negative correlation between the content of potassium and the content of calcium(n=15, p<0.01), which indicated that the sources of nutrient elements in peatland soil were different. The relatively large content of nutrient elements in peatland soil and the correlation between them might be related to the disturbance caused by the fire in history. The soil microbial respiration activity was relatively lower in this study area. The soil microbial biomass carbon and basal respiration rates were highest in the humus layer. With the increase of soil depth, soil microbial biomass carbon and basal respiration rates tended to be reduced, but the utilization rate of soil microorganisms on organic carbon could be increased and the energy that microbial activity required would be higher.