基于最小数据集沂蒙山区不同治理模式下的土壤质量评价

Soil Quality Evaluation with Different Treatment Models in Yimeng Mountainous Area Based on Minimum Data Set

沂蒙山区是北方土石山区水土流失治理重点区域,定量评价不同治理模式下的土壤质量,进而优选适宜的生态恢复措施,是推进沂蒙山区生态环境建设的关键。以沂蒙山区4种治理模式(乔草混交、土坎梯田+果树种植、撂荒、封禁植草)为研究对象,基于主成分分析、相关性分析和Norm值计算,对土壤养分、孔隙、水分、容重4类9项土壤属性指标进行筛选,构建土壤质量评价最小数据集。结果表明:(1)治理模式对土壤理化性质具有明显影响,硝态氮属于极敏感指标,全氮为高度敏感指标,而有机质、全磷、无机磷、田间持水量与饱和含水量属中度敏感指标,土壤容重为低度敏感指标;(2)影响沂蒙山区土壤质量的最小数据集指标包括全氮、土壤孔隙度、容重,经总数据集验证所构建的最小数据集可体现沂蒙山区土壤质量有效信息、准确性较高;(3)沂蒙山区不同治理模式下土壤质量指数介于0.41~0.53,土壤质量属于中等水平,且0—5 cm和5—10 cm土层的土壤质量指数较10—20 cm分别增加136.20%和37.60%。土壤质量表现为乔草混交>土坎梯田+果树种植>撂荒>封禁植草。综上,在水土流失严重、土壤较为贫瘠的沂蒙山区,生态恢复措施应以乔草混交模式为主。

Yimeng mountainous area is regarded as the key area for soil erosion control in the earth-rocky mountain areas of northern China. It is greatly necessary to make quantitative evaluation for soil quality with different treatment models and then to determine optimum treatment for ecological remediation, which is helpful to promote ecological environment construction in Yimeng mountainous area. This study took four treatment models as the research object: arbor-grass mixture, ridge terrace + orchard planting, fallow land, and banned + grass planting. In order to construct minimum data set for soil quality evaluation, nine soil attribute indices of soil nutrient, pore, water content, and soil bulk density were selected with the combined methods of principal component analysis, correlation analysis, and the calculation of Norm value. The results showed that soil physical and chemical characteristic pronouncedly varied with the change of treatment models;nitrate nitrogen was extremely sensitive indicator, and total nitrogen was highly sensitive indicator, while soil organic matter, total phosphorus, inorganic phosphorus, field capacity, saturated water capacity were moderately sensitive indicators, and bulk density were lowly sensitive indicator;three indicators including total nitrogen, soil porosity, and soil bulk density were identified as the key indicators for soil quality evaluation in the minimum data set;the verification of total data set suggested that the minimum data set could reflect the effective information and accuracy evaluation for soil quality in Yimeng mountainous area;soil quality index ranged from 0.41 to 0.53, which indicated that soil quality with different treatment models in Yimeng mountainous area was on the middle level;meanwhile, soil quality index in the 0—5 cm and 5—10 cm soil layer increased by 136.20% and 37.60% relative to that in the 10—20 cm soil layer, respectively;soil quality with different treatment models ranked in order: arbor-grass mixture>ridge terrace + orchard planting>fallow land>banned + grass planting. Therefore, the model of arbor-grass mixture was the optimal ecological remediation measure in Yimeng mountainous area with serious soil erosion and impoverished soil.