杨振奇, 秦富仓, 李龙, 任小同, 钱秋颖, 韩君. 砒砂岩区小流域土壤有机质空间分布特征及其影响因素[J]. 农业工程学报, 2019, 35(17): 154-161. DOI: 10.11975/j.issn.1002-6819.2019.17.019
    引用本文: 杨振奇, 秦富仓, 李龙, 任小同, 钱秋颖, 韩君. 砒砂岩区小流域土壤有机质空间分布特征及其影响因素[J]. 农业工程学报, 2019, 35(17): 154-161. DOI: 10.11975/j.issn.1002-6819.2019.17.019
    Yang Zhenqi, Qin Fucang, Li Long, Ren Xiaotong, Qian Qiuying, Han Jun. Spatial distribution characteristics of soil organic matter and its influencing factors in small watershed of feldspathic sandstone region[J]. Transactions of the Chinese Society of Agricultural Engineering (Transactions of the CSAE), 2019, 35(17): 154-161. DOI: 10.11975/j.issn.1002-6819.2019.17.019
    Citation: Yang Zhenqi, Qin Fucang, Li Long, Ren Xiaotong, Qian Qiuying, Han Jun. Spatial distribution characteristics of soil organic matter and its influencing factors in small watershed of feldspathic sandstone region[J]. Transactions of the Chinese Society of Agricultural Engineering (Transactions of the CSAE), 2019, 35(17): 154-161. DOI: 10.11975/j.issn.1002-6819.2019.17.019

    砒砂岩区小流域土壤有机质空间分布特征及其影响因素

    Spatial distribution characteristics of soil organic matter and its influencing factors in small watershed of feldspathic sandstone region

    • 摘要: 为了探究砒砂岩区小流域土壤有机质空间分布特征,该文以砒砂岩区典型流域鲍家沟小流域为研究对象。采用网格法布设取样点,2018年7月取样,按照0~20、>20~40、>40~60 cm划分取样层次。采用重铬酸钾外加热法测定土壤有机质,采用激光粒度测定仪测定土壤粒度,采用样方拍照法计算植被覆盖度。运用地统计学和约束性排序相结合的方法,研究环境因子影响下砒砂岩区土壤有机质的空间变异特征。结果表明:砒砂岩区小流域土壤有机质质量分数在0.98~15.45 g/kg之间,不同地形土壤有机质含量呈沟底>坡面>山脊的规律;研究区土壤有机质的空间分布规律可以用半方差函数的指数模型进行良好的模拟,块金效应在55.1%~57.5%范围内,属中等程度变异。小流域土壤有机质呈中间高边缘低的规律;冗余分析的结果显示,第1轴的特征值为0.58,解释量为58%,第1轴对响应变量的累积解释量为96.1%,前两轴对响应变量的累计解释量达到了99.3%。各环境因子与第1排序轴的相关系数大小顺序为植被覆盖度>土壤侵蚀程度>土壤颗粒平均粒径>坡位>高程>坡度,第1排序轴可以定义为植被-土壤侵蚀因子,坡度因子与第2排序轴的相关系数高于其他环境因子,第2排序轴可以定义为坡度因子。植被覆盖度是影响砒砂岩区小流域土壤有机质空间变异的主导因素,土壤侵蚀程度是决定土壤有机质垂向变异的关键因素。砒砂岩区的土层浅薄且贫瘠的地带,不宜开展大面积的整地和造林工作,而土层深厚且水肥条件良好的区域可以营造合理密度的灌木林、乔木林以及经济林。

       

      Abstract: Abstract: Feldspathic sandstone region is one of the main coarse sand source regions in the middle reach of Yellow River. Feldspathic sandstone region features complex and diverse landform with ravines and gullies criss-cross. It is a key region for implementing soil and water conservation and ecological restoration in China. Studying the spatial distribution characteristics of soil organic matter (SOM) had great significance to guide vegetation construction and reduce the input of coarse sand into Yellow River. Baojiagou small watershed is the most typical watershed among Feldspathic sandstone regions with the basin area of 12.67 km2. Thanks to the ecological immigration policy, the watershed is uninhabited and unaffected by a human presence. According to the results of the survey of the current situation of land use types in Baojiagou small watershed, forest and grassland are the main types of land use. Sampling points were set up by the grid method. In July and of 2018, soil samples were collected from 0-20, >20-40 and >40-60 cm in the plots under each samples. SOM contents were analyzed using sulfate digestion method with potassium dichromate and soil mechanical composition was measured by laser particle-size analyzer. Vegetation coverage was analyzed using photographic measurement. In this research, we studied the relationships between SOM and environmental factors in Baojiagou watershed through geostatistics analysis and constrained ordination. The results showed that soil organic matter content range from 0.98 to 15.45 g/kg. Ranking of SOM content according to topographic factors was: valley floor>slope> ridge. Exponential model fitted best to the semi-variance functions of soil organic matter content in the study areas, and the spatial variability of soil organic matter was at medium level, with the nugget effect ranging from 55.1 % to 57.5 %. SOM contents in the center parts of the study area were relatively high, whereas those in the edge parts were low. Redundancy analysis (RDA) demonstrated that the first axis and the second axis explained 96.1% and 2. 8% of the total variables of the SOM, The first two axes explained 99.3% of the relationship between the SOM and environmental factors. The correlation coefficient order of each environmental factor and the first ranking axis was the vegetation coverage > soil erosion degree > soil particle diameter > slope position > elevation > slope. Vegetation coverage and soil erosion degree had the greatest correlation with the first ranking axis, which was defined as vegetation-soil erosion factor, and slope factor had the largest correlation coefficient with the second ranking axis, which was defined as slope factor. Vegetation coverage was the dominant factor affecting the spatial distribution characteristics of SOM, soil erosion degree was the main factor affecting the vertical spatial distribution characteristics of SOM in feldspathic sandstone region. This paper suggests that in the shallow soil layer area, it is not suitable to carry out large scale land preparation and afforestation work and sealing measures should be taken. Trees can be planted in gully areas with deep soil and good water and fertilizer conditions.

       

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