土壤质地及容重和含水率对其导气率影响的实验研究

Effects of soil texture,bulk density and moisture content on soil air permeability

在室内利用一维瞬态法对重新装填的棕壤土、土、黄绵土和盐碱土等四种土壤的导气率进行了测量,分析了容重、含水率及冰冻等因素对土壤导气率的定量影响,以明确土壤类型、容重、含水率、冰冻与土壤导气率的关系。实验结果表明:土壤质地和结构对导气率有明显的影响,同一容重条件下土和棕壤土导气率接近,均显著高于黄绵土,在所设的四个容重条件下盐碱土导气率均为最低,仅为土和棕壤土导气率的3%～4%;四种土壤的导气率均随着容重的增加而减小,同种土壤最大容重(1.5 g.cm-3)下的导气率较之最小容重(1.2 g.cm-3)下降75%～85%,并且导气率与容重之间存在显著的指数函数关系;其他因素一致的条件下,土壤导气率随着含水率的增加而减小,导气率与含水率之间亦存在显著的指数函数关系;冰冻后土壤导气率较冰冻前显著降低,在本实验条件下含水率越低冻结后导气率下降越显著。

In laboratory,air permeability of reload brunisolic soil,lou soil,loessal soil and saline-alkali soil are measured by the one-dimensional transient method,soil bulk density,moisture content,frozen and other factors’ quantitative impact on the air permeability are analyzed,which are to make clear the relationship among the soil type,bulk density,moisture content,frozen and soil air permeability.Experimental results show that： soil texture and structure have a significant effect on the rate of air conductivity, in the same bulk density conditions,the air permeability of lou soil is close to that of brunisolic soil,and the air permeability of the two kinds of soil above are significantly higher than that of loessal soil.Saline-alkali soil air permeability are the lowest in the four bulk density,only 3% to 4% of the rate of lou soil and brunisolic soil;The air permeability of the four kinds of soil decreases with the increase of bulk density,the air permeability in maximum bulk density（1.5 g·cm-3） decreases by 75% to 85% compared to the minimum bulk density（1.2 g·cm-3） of the same kind of soil,and there is a significant exponential relationship between air permeability and bulk density;With other factors in the same conditions,the soil air permeability decreases with the increase of moisture content,there is also a significant exponential relationship between air permeability and moisture content;The frozen soil air permeability is much lower than that before freezing,the air permeability declines more significant in lower moisture content under given experimental conditions.