西鄂尔多斯地区5种荒漠优势灌丛生物量分配格局及预测模型

以西鄂尔多斯地区5种荒漠优势灌丛（沙冬青（Ammopiptanthus mogolicus）、四合木（Tetraena mongolica）、霸王（Zygophyllum xanthoxylum）、红砂（Reaumuria songarica）、半日花（Helianthemum songaricum））为研究对象，采用平均标准灌丛全部收获法测定灌丛各营养器官（枝条、叶片、根系）生物量，并分别以丛高（H）和冠幅（C）的复合因子（CH）及基径（D）和丛高（H）的复合因子（D²H）为自变量建立单株灌丛生物量预测模型。通过决定系数（R²）、估计值的标准误差（SEE）和F检验显著水平筛选出各灌丛种最佳生物量预测模型。结果表明：（1）5种荒漠灌丛单株总生物量干鲜比差异性显著（P<0.05），各营养器官间差异性也达到显著水平（P<0.05）；灌丛根冠比种间差异显著（P<0.05），红砂（1.05）> 霸王（1.01）> 半日花（0.92）> 沙冬青（0.90）> 四合木（0.49）；（2）根系和枝条是荒漠灌丛生物量的主要贡献者，其生物量占灌丛总生物量比例之和均在80%以上，根系生物量分配随根系径级的增加而增加；（3）5种荒漠优势灌丛单株灌丛生物量预测模型R²值均在0.85以上，且在0.05水平上显著，生物量模型预测精度较高。

Biomass Allocation Patterns and Estimation Model of Five Desert Shrub Species in West Ordos Region

In this paper, the main desert shrub species: Ammopiptanthus mogolicus, Tetraena mongolica, Zygophyllum xanthoxylum, Reaumuria songarica, Helianthemum songaricum shrub were taken as the research objects in west Ordos region, Inner Mongolia autonomous region, China. The average standard shrub harvest method was used and each part (branch, leaves and roots) biomass of shrub was measured in field. Shrub height (H) combined respectively by crown area(C) as CH and diameter (D) as D²H was used as independent variable to establish the biomass model. The optimal models were selected according to the largest determination coefficient (R²), the smallest standard error of estimate (SEE) and significance level of F test. The results showed that the differences among the dry/fresh weight ratio of single shrub and the differences among parts of shrub reached a significant level (P<0.05).The differences among root-shoot ratio of five shrub species reached a significant level (P<0.05). The root-shoot ratio of five shrub species was respectively that Reaumuria songarica was 1.05, Zygophyllum xanthoxylum was 1.01, Helianthemum songaricum was 0.92, Ammopiptanthus mogolicus was 0.90, Tetraena mongolica was 0.49. The roots and branches were main contributors to total biomass of desert shrubs and the proportion of roots and branches biomass to total biomass reached above 80%.With the increase of root diameter class, the root biomass was increasing. The R² value of single shrub biomass models were all more than 0.85 and reached a significant level (P<0.05). The prediction accuracy of five desert shrubs' biomass models were good. The important basic data was provided by this research results and theoretical basics for the response of shrub productivity, carbon storage and carbon cycle to global climate changes in desert area of western China.