施加生物质炭对滨海盐碱土壤水分运移的影响

Effects of Biochar on Water Movement in Coastal Saline-alkali Soil

【目的】探究施加生物质炭对滨海盐碱土壤水力学特性的影响机制。【方法】通过室内模拟入渗实验,研究不同生物质炭施加量(质量分数分别为0%、0.3%、0.5%、0.8%、1.0%、3.0%、5.0%、8.0%)对典型滨海盐碱土壤水分导水入渗及持水性能的影响。【结果】供试土壤水分入渗速率和饱和导水率随生物质炭施加量增加呈先增大后减小趋势,生物质炭施加量<1.0%有助于供试土壤水分入渗,生物质炭施加量>1.0%则制约供试土壤导水性。1.0%生物质炭施加量是影响土壤水分入渗和土壤导水性的重要转折点。施加生物质炭能够显著提升滨海盐碱土壤的持水能力,且随着生物质炭施加量的增加而增加,但过量施加生物质炭降低了土壤渗透性,不利于提高滨海土壤的导水性。【结论】0.8%~1.0%的生物质炭施加量对滨海盐碱地改良成效较好。

【Objective】Investigating the influence mechanism of biochar application rate on the hydraulic characteristics of coastal saline-alkali soil.【Method】By conducting indoor simulation infiltration experiments,the effects of different biochar application rates(mass fractions of 0%,0.3%,0.5%,0.8%,1.0%,3.0%,5.0%,8.0%)on the water infiltration and water-holding capacity of typical coastal saline-alkali soil were studied.【Result】The infiltration rate and saturated hydraulic conductivity of the tested soil increased first and then decreased with the increase of biochar addition.<1.0%biochar application rate facilitated soil water infiltration,while>1.0%biochar application rate constrained the hydraulic conductivity of the tested soil.The 1.0%biochar application rate represented a significant turning point affecting soil water infiltration and conductivity.Biochar application significantly enhanced the water-holding capacity of the coastal saline-alkali soil,and it increased with the biochar content.However,excessive biochar application rate reduced soil permeability,which was not conducive to improving the hydraulic conductivity of coastal soil.【Conclusion】As a conditioner,biochar will achieve better remediation results when added to coastal saline-alkali soils at an application rate of 0.8%-1.0%.