定边县板凳滩移民区土壤发生特性与系统分类研究

Soil Characteristics and Taxonomic Classification in Bandengtan Resettlement Area of Dingbian County,Shaanxi Province

通过对陕西省定边县板凳滩移民区2 500hm2未利用地的调查及不同深度剖面土样的分析,研究了不同地形和不同植被下土壤的发生特性及系统分类。项目区内土壤没有完整的发生层次;土壤颜色、结构和养分在剖面层次上无明显差异;土壤有机质含量较低,最高1.7871g/kg,最小0.201 7g/kg;土壤碳酸钙无明显的淋溶淀积,剖面中无淀积层;颗粒组成以2～0.02mm粒级的砂粒为主;土壤CEC集中分布在2.5～5cmol/kg,保肥性能差。通过诊断层和诊断特征分析,研究区土壤共分属1个土纲,1个亚纲,2个土类和4个亚类,其中剖面Ⅱ1属于弱盐潮湿砂质新成土,剖面Ⅱ5属于钠质潮湿砂质新成土,剖面Ⅲ4属于石灰潮湿砂质新成土,剖面Ⅵ4属于石灰干润砂质新成土。研究结果可为移民区的土壤资源综合评价、土壤适宜性评价及农、林、牧业合理布局提供依据。

Genesis properties and taxonomic classification in different types of topography and under different degrees of vegetation coverage are studied through the investigation of a 2 500 hm2 unused land and the analysis of soil samples at different depths in the Bandengtan resettlement area of Dingbian County,Shaanxi Province.In the study area,soil genesis layers are not complete,and profile differences in soil color,soil structure,and soil nutrients are not distinct.Soil organic matter content is rather low,with a maximum content of 1.787 1 g/kg and a minimum content of 0.201 7 g/kg.There are no distinct eluviation and deposition of soil calcium carbonate and no distinct deposition layer in the profile.Sand（2~0.02 mm） is the main particle composition.The CEC concentrates at 2.5~5 cmol/kg,indicating a poor soil fertility.From the diagnostic horizons and their characteristics analysis,soils in the area belongs to 1 soil order,1 suborder,2 groups,and 4 subgroups,in which Ⅱ1 belongs to Parasalic Aqui-Sandic Primosols;Ⅱ5,Sodic Aqui-Sandic Primosols;Ⅲ4,Calcaric Aqui-Sandic Primosols;and Ⅵ4,Calcaric Usti-Sandic Primosols.The results can be used as a reference to comprehensive soil resources evaluation,soil suitability evaluation,and the rational layout of agriculture,forestry,and animal husbandry.