| 摘要: |
| 【目的】分析宁南山区不同林龄杏树地土壤的干层特征，明确林龄对该地区杏树地土壤干层、干燥化程度的影响。【方法】以自然条件下农田为对照，分析比较宁南山区彭阳县王洼流域3，17，23，35年林龄杏树地土壤0～600 cm土层含水率、干层起始深度、干层厚度；采用土壤水分相对亏缺指数及干燥化指数对土壤干层程度进行定量评价，同时对土壤干层影响因素进行冗余分析。【结果】3，17，23，35年林龄杏树地土壤平均含水率分别为15.58%，12.79%，11.54%，11.24%，林龄越长的杏树地土壤含水率越低，3年林龄杏树地与其他林龄杏树地土壤含水率之间存在显著差异（P＜0.05）。除3年林龄杏树地外，其他林龄杏树地土壤干层起始深度随林龄的增加而向表层发展，干层厚度随林龄的增加而增加；3，17，23，35年林龄杏树地剖面土壤水分相对亏缺指数均值分别为-0.16，0.29，0.45，0.53，林龄越长土壤水分亏缺越严重，除0~100 cm土层外，其余各层土壤水分亏缺均值均随林龄的增加而呈增大趋势。3，17，23，35年林龄杏树地的平均土壤干燥化指数分别为184.36%,99.87%,74.60%,59.15%，即林龄越长其干燥化程度越强。冗余分析表明，坡度及杏树林龄、胸径、冠幅、株高等是导致研究区土壤干燥化的主要原因。【结论】林龄越长的杏树地土壤干燥化程度也越强，建议对杏树林采取科学合理的修剪措施，并通过调整种植密度、结构等缓解土壤干层现象的发生。 |
| 关键词: 宁南山区 杏树地 土壤干层特征 土壤干燥程度 林龄 冗余分析 |
| DOI： |
| 分类号: |
| 基金项目:国家自然科学基金项目(41867003,41761049)；宁夏自然科学基金项目(2018AAC03027)；宁夏回族自治区科技重大专项（2018BEG02010）；宁夏环境保护科学技术研究项目（2018-007） |
|
| Evolution of dry layer of apricot land at different ages in southern Ningxia mountain areas |
|
BAO Weibin,WANG Youqi,LIU Peng,et al
|
| Abstract: |
| 【Objective】The characteristics of dry layer of apricot soil at different forest ages in southern Ningxia mountain area were analyzed,and the effects of forest age on dry layer and drying degree were clarified.【Method】In this study,soil water content,starting depth and thickness of dry layer of 0-600 cm soil in the forests at ages of 3,17,23 and 35 years in the Wangwa basin of Pengyang County were analyzed and compared using farmlands under natural conditions as control.The drying degree was evaluated based on soil moisture deficit index and desiccation index,and redundancy analysis was conducted to identify influencing factors.【Result】Longer apricot planting years had lower soil moisture content. The average soil moisture contents of apricot lands at the ages of 3,17,23 and 35 years were 15.58%,12.79%,11.54% and 11.24%,respectively.There was significant difference between 3 year apricot land and other ages (P<0.05).Except for 3 years old apricot land,the initial depth of soil dry layer developed to the surface layer with the increase of forest age,and the thickness of dry layer increased with the increase of forest age.The average relative deficit indexes of soil moisture of apricot lands at ages of 3,17,23 and 35 years were -0.16,0.29,0.45 and 0.53,respectively.Longer the planting years also showed more serious soil water deficit.Except for the 0-100 cm soil layer,the average soil water deficit in other layers increased with the increase of forest age.The average drying indexes of apricot lands at ages of 3,17,23 and 35 years were 184.36%,99.87%,74.60% and 59.15%,respectively.In other words,the drying index increased as the increase of planting age.Redundancy analysis showed that slope,apricot tree age,diameter at breast height of apricot,crown width and plant height were the main reason for soil drying in the study area.【Conclusion】The extension of planting years increased soil desiccation intensity of apricot soil.Scientific and reasonable pruning measures and adjusting planting density and structure are suggested for alleviating the occurrence of dry soil layer. |
| Key words: southern Ningxia mountain area apricot field characteristics of soil dry layer degree of soil dryness planting years redundancy analysis |
