不同初始条件对砂姜黑土收缩特征的影响

发布时间：2018-05-07 00:35

本文选题：砂姜黑土 + 容重　；参考：《农业机械学报》2017年10期

【摘要】：利用离心机法,分别测定了初始容重为1.10、1.22、1.31 g/cm3,初始含水率为49.34%、43.55%、36.03%、31.93%和25.51%以及砂姜质量分数为0、4%、6%、8%、10%和12%的砂姜黑土样品在不同吸力下的土壤体积含水率及收缩特征。结果表明:在考虑土壤收缩变形的情况下,相比VG模型,Gregory模型可以更好地拟合砂姜黑土的水分特征,砂姜黑土含水率随着土样初始容重及初始含水率增加而增加,随着砂姜含量增加而降低。收缩过程中,在不同初始容重处理下,初始容重增加,土壤的线缩率减小,土壤收缩后容重增加比例下降;且初始容重增加显著提高了土壤结构收缩段孔隙收缩比例,降低了线性收缩段孔隙收缩比例。在不同初始含水率处理下,初始含水率越高,土壤线缩率及收缩后的容重越大;当初始含水率为36.03%时,土壤结构收缩段孔隙收缩比例最高,线性收缩段孔隙收缩比例较低。在不同砂姜含量处理下,砂姜含量的提高减小了线缩率及土壤收缩后的容重,增加了土壤总孔隙比。因此,对于砂姜黑土而言,在一定范围内,提高土壤容重以及降低土壤含水率可以减少土壤收缩;而在砂姜含量较高的情况下,主要应防止由于大孔隙存在而引起的水分流失。
[Abstract]:Using centrifuge method, the soil volume water content and shrinkage characteristics of sand ginger black soil samples with initial bulk weight of 1.10 ~ 1.22g / cm ~ (3), initial water content of 49.34 ~ 43.55U ~ (36.03)% and 25.51% and sand mass fraction of 0 ~ 4 ~ 4 ~ (8)% and 12% ~ (12)% were measured respectively. The results showed that compared with VG model and Gregory model, the moisture content of shajiang black soil increased with the increase of initial bulk density and initial moisture content. With the increase of ginger content, it decreased. In the process of shrinkage, under different initial bulk density treatments, the initial bulk density increased, the linear shrinkage rate of soil decreased, and the proportion of bulk density increased after soil shrinkage decreased, and the initial bulk density increased significantly the pore shrinkage ratio of soil structure shrinkage section. The porosity shrinkage ratio of linear shrinkage section is reduced. When the initial moisture content is 36.03, the shrinkage ratio of soil structure is the highest, and the shrinkage ratio of linear shrinkage section is lower than that of linear shrinkage section. The higher the initial moisture content is, the larger the linear shrinkage ratio is and the larger the bulk density is after shrinkage, and when the initial moisture content is 36.03, the shrinkage ratio of pores in the shrinkage section of soil structure is the highest. Under different ginger content, the increase of ginger content decreased the shrinkage rate and bulk density of soil after shrinkage, and increased the total porosity of soil. Therefore, for shajiang black soil, increasing soil bulk density and reducing soil moisture content can reduce soil shrinkage within a certain range, but in the case of high content of ginger, the water loss caused by the existence of macropores should be prevented.
【作者单位】：中国农业大学资源与环境学院;农业部华北耕地保育重点实验室;安徽省农业科学院土壤肥料研究所;
【基金】：“十二五”国家科技支撑计划项目(2012BAD05B00) 国家重点研发计划项目(2016YFD0300804-3)
【分类号】：S152

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