| 摘要: |
| 【目的】研究毛乌素沙地砒砂岩与风沙土（其中砂粒含量为95.31%）不同质量比复配土壤的持水情况，为砒砂岩改良风沙土的应用提供参考。【方法】将砒砂岩与风沙土分别按0∶1，1∶5，1∶2，1∶1，2∶1，5∶1和 1∶0的质量比复配，采用离心机法测定各复配土壤在不同水吸力（1，3，5，7，10，30，50，70，100，200，300，500，700，1 000和1 200 kPa）下的容积含水量，利用Gardner模型拟合并绘制其水分特征曲线，计算各复配土壤在各水吸力下的比水容量、田间持水量、萎蔫系数、有效水含量和毛管孔隙度及有效水孔隙度。【结果】Gardner模型能很好地拟合7种砒砂岩与风沙土不同质量比复配土壤的水分特征曲线，随着砒砂岩质量的增加，水分特征曲线逐渐右移；在同一水吸力（1～1 200 kPa）条件下，复配土壤含水量和比水容量均随砒砂岩质量的增加而增大。当砒砂岩质量大于或等于风沙土时，比水容量出现10-2数量级时的水吸力值为200 kPa，此时比水容量较高，土壤供水能力较强；当砒砂岩质量小于风沙土时，比水容量出现10-2数量级时的水吸力值为100 kPa（当全为风沙土时，此条件下的水吸力值为70 kPa），此时土壤向作物供水的能力相对较弱。随着复配土壤中砒砂岩质量的增加，其田间持水量由4.46%增加到17.32%，全有效水含量由3.17%增加到8.37%，萎蔫系数由1.29%增加到8.96%；毛管孔隙度先减小后增大，呈二次函数趋势变化；而有效水孔隙度呈指数型增长，由7.82%增加到15.35%。【结论】砒砂岩与风沙土复配后，复配土壤的持水保水能力随砒砂岩质量的增加而增强，但以砒砂岩与风沙土按5∶1质量比进行复配为宜。 |
| 关键词: 砒砂岩 风沙土 复配土壤 水分特征曲线 Gardner模型 土壤改良 |
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| 基金项目:国土资源部公益性行业科研专项（201311005）；陕西省科技新星计划项目(2011KJXX60)；陕西省农业攻关计划项目（2012K01-34） |
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| Water-holding characteristics of compounded soil with feldspathic sandstone and aeolian sandy soil |
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ZHANG Lu,HAN Ji-chang,LUO Lin-tao,et al
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| Abstract: |
| 【Objective】We studied the water retention properties of compound soil with feldspathic sandstone and aeolian sandy soil (the content of sand was 95.31%) by different mass ratios in Mu Us Sandy Land,to improve the application of feldspathic sandstone to aeolian sandy soil.【Method】Mixing Feldspathic sandstone and aeolian sandy soil were mixed with mass ratios of 0∶1,1∶5,1∶2,1∶1,2∶1,5∶1 and 1∶0.Centrifuge method was used to measure the soil volume moistures of each compound soil with various suctions（1,3,5,7,10,30,50,70,100,200,300,500,700,1 000 and 1 200 kPa）.Gardner model was used to fit and draw water characteristic curves and specific water capacity,field capacity,permanent wilting coefficient,available water content,capillary porosity and available water porosity were calculated.【Result】Gardner model well fitted water characteristic curve for each compound soil of feldspathic sandstone and aeolian sandy soil.With the increase of feldspathic sandstone mass ratio,the water characteristic curves gradually moved to the right.With identical suction (1-1 200 kPa),the compound soil moisture content and specific water capacity increased as the mass ratio of feldspathic sandstone.When mass ratio of feldspathic sandstone was no less than that of aeolian sandy soil, the suction was 200 kPa with large water capacity and strong water supply capacity when specific water capacity was 10-2.When mass ratio of feldspathic sandstone was less than that of aeolian sandy soil,the suction was 100 kPa with weak soil water supply capacity when specific water capacity was 10-2(the suction for pure aeolian sandy soil was 70 kPa).As the increase of feldspathic sandstone mass ratio in compound soil, field water capacity increased from 4.46% to 17.32%,total available water content increased from 3.17% to 8.37%,and permanent wilting coefficient increased from 1.29% to 8.96%.The capillary porosity decreased first followed by increase with quadratic function trend while the available water porosity increased exponentially from 7.82% to 15.35%.【Conclusion】Water holding capacity of compound soil increased as the increase of feldspathic sandstone mass ratio,and the best mass ratio of feldspathic sandstone to aeolian sandy soil was 5∶1. |
| Key words: feldspathic sandstone aeolian sandy soil compound soil water characteristic curve Gardner model soil improvement |
