羊草草地分解者亚系统能量流动研究

【作者】 王娓；

【导师】 郭继勋；

【作者基本信息】 东北师范大学 ， 生态学， 2002， 博士

【摘要】 本论文以东北羊草草地典型羊草群落和碱茅群落为研究对象，通过2000-2001两年的野外测定和室内分析，完成了羊草草地分解者亚系统能量流动的研究工作。应用收获法和重量损失法对枯枝落叶输入与分解的季节动态及其与环境因子的关系进行了研究；应用静态气室法测定了土壤总呼吸和凋落物呼吸，应用土壤呼吸量与地下生物量线性回归趋势线法测定了土壤微生物呼吸及根呼吸的贡献量，运用相关分析法建立了土壤总呼吸、根呼吸、土壤微生物呼吸及其凋落物呼吸季节动态与环境因子之间的数学模型；应用灰色分析比较了两群落土壤呼吸季节动态产生差异的原因；应用干重换算法对土壤微生物能量积累量的季节动态进行了测定，建立了土壤微生物能量积累量与环境因子的数学模型；应用系统分析方法，利用分室模型，对两群落枯枝落叶与微生物之间的能量流动进行了定量测定和稳定性分析。 1．羊草群落枯枝落叶年输入量为124.8g.m^-2，碱茅群落为99.8g.m^-2，两群落枯枝落叶输入量的季节动态均与温度、降水量和地上绿色体生物量呈负相关。两群落枯枝落叶分解速率均于8月达最大值，分别为4.285mg.g^-1.d^-1和8.109mg.g^-1.d^-1，均与地温、土壤含水量呈正相关，与土壤有机质含量和土壤碳氮比呈负相关。 2．羊草群落昼夜二氧化碳释放速率为0.3908gC.m^-（2）.hr^-1，碱茅群落为0.83gC.m^-2.hr^-1，两群落均于11-13时达最大值，1时达最小值，均与地表温度呈对数正相关；羊草群落土壤呼吸速率于8月份出现最大值12.66gC.m^-2.d^-1，碱茅群落于7月份达最大值11.4gC.m^-2.d^-1；两群落土壤呼吸速率均与地温、降水量、土壤含水量、空气相对湿度、绿色体生物量、枯枝落叶分解速率呈正相关，与土壤碳氮比和地表凋落物量呈负相关；羊草群落的灰色关联序为：pH（0.4702）＞风速（0.4194）＞0-10cm土壤含水量（0.397）＞10-20cm土壤含水量（0.3932）＞20-30cm土壤含水量（0.3764）＞孔隙度（0.3705）＞相对湿度（0．3576）＞有机质（0．306）＞C／N（0．2776）＞10Clll地温（0．2422）＞降水量（0．1716）；碱茅群落的灰色关联序为：0－10cm土壤水分含量（0．4835）＞洲（0．3999）＞风速（0．3877）＞孔隙度（0．3559）＞有机质（0．3473）＞10cm地温（0．3386）＞10－20cm土壤水分含量（0．3287）＞C／N（0．2915）＞相对湿度（0．2661）＞2030cm土壤水分含量（0．256）＞降水量（0．1892）。 3．羊草群落和碱茅群落根呼吸占土壤总呼吸比例在生长季节内分别为52％和49％，其变化幅度分别为38％－71％和31％－73％；羊草群落根呼吸在8月达最大值5．37gC．f‘．d－‘；碱茅群落于6月达到最大值4．52gC．nf’．d－‘；两群落根呼吸均与土壤温度、土壤含水量、地上生物量和地下生物量呈正相关。 4．羊草群落和碱茅群落土壤微生物呼吸速率均在7月达最大值分别为5．64gC．／．d－‘和5．06gC．矿．d－‘，羊草群落土壤微生物能量损耗速率与地表温度、降水及土壤表层含水量（0－20CC）、绿色体生物量呈正相关；碱茅群落能量损耗速率同降水量、土壤表层含水量（0－20cm）、地上生物量和地下生物量呈线性正相关。两群落土壤微生物呼吸均为在生长发育初期贡献率最大，在生长发育末期最小。 5．羊草群落、碱茅群落凋落物呼吸均在7月达最大值，分别为0．88 gC．In’．d－‘和1．59 gC．In’．d－‘，5刁月期间凋落物呼吸速率羊草群落为：－0．001 gC。《．d叫，碱茅群落为 0．618 gC．才．d＼ 羊草群落凋落物呼吸与温度、土壤含水量呈正相关，碱茅群落凋落物呼吸速率与地温呈线性正相关。 6．羊草群落和碱茅群落土壤微生物能量积累量均于8月份达最大值，分别为183．67U．m－‘和180．86kJ．卜’，羊草群落与土壤含水量、地上生物量和枯枝落叶分解速率呈线性正相关，与土壤有机质含量和土壤碳氮比均呈对数负相关。碱矛群落与土壤含水量呈线形正相关。 7．羊草群落枯枝落叶中能量含量为 1834．02 kJ．In‘．a‘，被微生物利用的能量为652．93 kJ．m”．a－‘，微生物在呼吸作用中消耗的能量为 469．26 kJ．In’．a‘，构成微生物生物量的能量为 183．67 kJ．m’．a‘；每年积累的枯枝落叶约需8年可全部分解；碱茅群落枯枝落叶中能量含量为 1357．84 kJ．m’．a’，被微生物利用的能量为 7朋．15 k1 m’．a－‘， IV 一微生物在呼吸作用中消耗的能量为552．29 kJ．m’．a－‘，构成微生物生物量的能量为 IS0．86 kJ。‘．a‘；每年积累在地表的95％凋落物分解约需4年。更多还原

【Abstract】 This paper was focused on typical Aneurolepidium chinense community and Puccinellia tenuiflora community in Songnen Grassland and the research work about energy flow of decomposer subsystem of Aneurolepidium chinense grassland was completed through field and laboratory experiments during the period from 2000 to 2001. The work on seasonal dynamics of litter input and decomposition and the relationship between them and environmental factors was studied through the method of harvest and weight loss. Soil respiration rate was measured by alkali-absorption method and the contribution from soil microorganism respiration and from root respiration was determined through trendline method of linear regression between soil respiration rate and belowground biomass. Mathematical models were established between the seasonal dynamics of main components of soil total respiration including soil respiration, root respiration, soil microorganism respiration, litter respiration and environmental factors. Grey-analysis was used to compare the difference of seasonal dynamics of soil respiration between Aneurolepidium chinense community and Puccinellia tenuiflora community. Dry-weight conversion method was used to measure the seasonal dynamics of energy accumulation of soil microorganism and mathematical models between energy accumulation and environmental factors were established. Compartment model was applied to describe the energy flow between litter and soil microorganism and stabilization analysis was conducted.1. The annual input of litter was 124.8g.m-2 and 99.8g.m-2 in Aneurolepidium chinense community and Puccinellia tenuiflora community respectively. The litter input amount in the two communities was negatively correlated with soil surface temperature, precipitation and green biomass of plants. The maximum values of decomposition rate of Aneurolepidium chinense community and Puccinellia tenuifloracommunity were 4.285 mg-g^.d"1 and 8.109 mg.g^.d"1 respectively in August and was positively correlated with soil temperature, soil water content and negatively correlated with soil organic matter content and ratio between carbon and nitrogen of soil.2. The diurnal release rate of CO2 was 0.3908gC.m"2.hr~1 in Aneurolepidium chinense community and O.83gC.m-2.hr-1 in Puccinellia tenuiflora community with the maximum value in 11-13:00 and the minimum value in 1:00. The release rate of the two communities were positively correlated with soil surface temperature. The two communities had obvious seasonal dynamics of soil respiration. Soil respiration rate of Aneurolepidium chinense community reached the maximum value of 12.66gC.m-2.d-1 in August and that of Puccinellia tenuiflora community reached the maximum value of 11.4 gC.m-2.d-1 in July. The soil respiration rate of the two communities was positively correlated with soil surface temperature, precipitation, soil water content, relative humidity, green biomass and litter decomposition rate and was negatively correlated with ratio between carbon and nitrogen of soil and litter biomass of soil surface. The gray correlation order in Aneurolepidium chinense community was: pH (0.4702) > wind velocity (0.4194) > soil water content at 0-10cm depth (0.397)> soil water content at 10-20 depth (0.3932)> soil water content at 20-30cm depth (0.3764)> porosity(0.3705)> relative humidity (0.3576) > organic matter content of soil(0.306)> C/N (0.2776) > soil temperature at 0-10cm depth (0.2422)> precipitation amount (0.1716)and the gray correlation order in Puccinellia tenuiflora community was: soil water content at 0-10cm depth (0.4835)> pH(0.3999)> wind velocity (0.3877)> porosity (0.3559)> organic matter of soil (0.3473) >soil temperature at 0-1 Ocm depth (0.3386)> soil water content at 10-20cm depth (0.3287)> C/N(0.2915)> relative humidity (0.2661)> soil water content at 20-30cm(0.256)> precipitation amount(0.1892).3. The percentage of root respiration to soil respiration during growth period was 52% with the variation range of 38%-71% in更多还原