冀北坝上沙化土地沙棘人工林的生态效益

为明确沙棘人工林对冀北坝上沙化土地的改善效果，以坝上沙化土地的沙棘林为研究对象，通过设置样地，测定其风速并计算防风效能和地表粗糙度，研究沙棘林的防风固沙效应；通过设置样方，利用丰富度指数(R₀)、Simpson指数(D)、Shannon-Wiener多样性指数(H)、Pielou均匀度指数(E)分析沙棘林地和荒坡地植物物种丰富度和结构特点；通过做土壤剖面，测定沙棘林地和荒坡土壤的理化性质。结果表明，沙棘林地和荒坡的粗糙度均随着季节呈逐渐升高的趋势，且沙棘林地的粗糙度大于荒坡，防风效果显著；沙棘林地的草本植物种比荒坡多8种，物种更丰富，且群落结构更为稳定；沙棘林地各土层土壤的自然含水率、持水量、孔隙度和全氮、全磷、全钾、碱解氮、速效钾含量均显著高于荒坡，沙棘林地土壤pH值范围为6.24～7.08,土壤有机质含量在14.75～16.71 g/kg之间，均显著优于荒坡。由此可见，在冀北坝上沙化地区种植沙棘，可促进防风固沙，提高植物物种丰富度和改善土壤理化性质。

Ecological benefits of Hippophae rhamnoides plantation on desertification land in the Bashang area of north Hebei Province

To clarify the improvement effect ofHippophae rhamnoidesplantations on desertified land in the Bashang area of northern Hebei Province, this experiment tookH.rhamnoidesplantations as the research object. By setting up sample plots, measured wind speed and surface roughness, the effect of sea buckthorn forest on wind protection and sand fixation was studied. The richness index(R₀), Simpson index(D), Shannon-Wiener diversity index(H) and Pielou evenness index(E) were used to analyze the species richness and structure characteristics of seabuckthorn forest and barren slope. Measure the physical and chemical properties ofH.rhamnoidesplantations soil and barren slopes soil by making soil profiles. The results showed that the roughness both inH.rhamnoidesplantation and barren slope increased gradually with the season. However, roughness inH.rhamnoidesplantation was greater than that of barren slopes, and windproof effect was remarkable. There were 8 more herbaceous species inH.rhamnoidesplantations than on barren slopes, the species were more abundant and the community structure was more stable. The natural water content, water holding capacity, porosity, total nitrogen, total phosphorus, total potassium, alkali-hydrolyzable nitrogen and available potassium content of each soil layer ofH.rhamnoidesplantation land were significantly higher than those of barren slope. The soil pH range ofH.rhamnoidesplantation land was 6.24-7.08, and the soil organic matter content was between 14.75-16.71 g/kg, which was significantly better than that of barren slopes. It could be seen that planting seabuckthorn on desertification land in the Bashang area of the north Hebei Province could promote windbreak and sand fixation, increase plant species richness and improve soil physical and chemical properties.