渭北地区不同种植年限苹果园土壤有机碳分布特征

Distribution characteristics of soil organic carbon in apple orchard with different planting years in Weibei regions

目的探究种植年限对苹果园土壤有机碳含量及其分布特征的影响,为提高果园土壤肥力,增加果园产量提供参考依据。方法以渭北地区种植年限为5 a,10 a,15 a和20 a的苹果园为研究对象,利用重铬酸钾外加热方法测定苹果园土壤有机碳含量。结果(1)随着种植年限的增加,土壤有机碳含量的总体平均值呈现出先下降后上升的变化趋势,且不同年限之间差异性显著(P<0.05),其中,5 a苹果园中有机碳含量最高,为6.83 g/kg。(2)在距树干0.5 m,1 m,1.5 m水平方向上,除5 a果园土壤外,距树干越近,土壤有机碳含量越高。除15 a果园土壤外,不同种植年限果园土壤有机碳含量在距树干0.5 m,1 m,1.5 m处的变化趋势差异显著(P<0.05)。(3)垂直剖面上,在0~40 cm土层深度范围内,不同种植年限苹果园土壤有机碳含量波动幅度较大,随着土层深度的增加,有机碳含量呈减少趋势,此外,5 a苹果园土壤有机碳含量在200~320 cm深度显著增加。结论渭北地区不同种植年限苹果园土壤有机碳含量随着种植年限的增加,呈现出先下降后上升的变化趋势。水平方向上,不同种植年限果园在近干处有机碳含量高,对果园有机碳赋存的影响更大。垂直方向上,有机碳含量集中在浅层土壤,呈现出表聚特征。

Purposes—To investigate the influence of planting years on soil organic carbon content and the distribution characteristics in apple orchards,and to provide reference basis for improving soil fertility of the orchard and increasing orchard yield.Methods—Taking apple orchards with the planting years of 5 a,10 a,15 a and 20 a in Weibei regions as the research object,the soil organic carbon content of apple orchards was determined with potassium dichromate external heating method.Results—(1)With the increase of planting years,the soil organic carbon content of apple orchards with different planting years showed a tendency of decreasing and then increasing on the overall average,and there was a significant difference between different planting years(P<0.05),of which,the organic carbon content of apple orchards with planting years of 5 a was the highest,6.83 g/kg.(2)In the horizontal direction of 0.5 m,1 m and 1.5 m from the tree trunk,except for the soil in the orchard with planting years of 5 a,the closer to the tree trunk,the higher the soil organic carbon content.Except for the soil in the orchard with planting years of 15 a,the trend of soil organic carbon content in orchards with different planting years differed significantly from the trunk at 0.5 m,1 m and 1.5 m(P<0.05).(3)In the vertical profiles of different planting years,the organic carbon content of apple orchards with different planting years fluctuated greatly in the range of 0~40 cm soil depth,and showed a decreasing trend with the increase of the soil depth,and in addition,the soil in the apple orchard with planting years of 5 a showed a decreasing trend in the range of 0~40 cm soil depth,with the increase of the soil depth.In addition,the soil organic carbon content of apple orchards with planting years of 5 a increased significantly in the depth of 200~320 cm.Conclusions—The soil organic carbon content of apple orchards with different planting years in Weibei regions showed a tendency of decreasing and then increasing with the increase of planting years.In the horizontal direction,orchards with different planting years had high organic carbon content near the dryness,which had a greater influence on the organic carbon endowment of the orchards.In the vertical direction,the organic carbon content was concentrated in the shallow soil layer,showing the characteristics of epilimnion.