Department of Environmental Science, Zhejiang University, Hangzhou, 310058, China; Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Hangzhou, 310058, China; State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, 830011, China; Research Center for Ecology and Environment of Central Asia, Chinese Academy of Sciences, Urumqi, 830011, China; University of Chinese Academy of Sciences, Beijing, 100049, China.
Department of Environmental Science, Zhejiang University, Hangzhou, 310058, China; Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Hangzhou, 310058, China.
Environ Pollut. 2019 Oct;253:779-789. doi: 10.1016/j.envpol.2019.07.051. Epub 2019 Jul 11.
Biochar addition to soil may change the hydrophobicity of amended soil and influence soil hydraulic properties. Soil hydrophobicity, i.e. soil water repellency (SWR) can interrupt water infiltration and form preferential flow leading to a potential risk of soil erosion or groundwater pollution. Up to date, the effect of different biochars on soil hydrophobicity remains unclear and the association of SWR with soil hydraulic properties is still unknown. To link the biochar hydrophobicity to SWR and soil water holding capacity (WHC), the surface structure and chemical composition of 27 biochars with different feedstocks and pyrolysis temperatures were characterized, and the SWR and soil WHC of biochar-added soil were investigated. Carboxylic groups on the biochar surface, surface area and pore volume were mostly influenced by pyrolysis temperature, which suggested the dominant factor determining the severity of biochar hydrophobicity was pyrolysis temperature. Hydrophilic soil became hydrophobic after biochar amendment. A higher addition rate led to a stronger SWR of hydrophilic soil. Biochar addition increased soil WHC of hydrophilic soil with low total organic carbon (TOC) content. Biochar did not have significant influence on SWR and soil WHC of hydrophobic soil with high TOC content. It implied that the influence of biochar on SWR and soil hydraulic properties mainly depended on soil original hydrophobicity and TOC content. Therefore, the properties of biochar and influence on soil hydrophobicity and hydraulic properties should be considered before processing biochar application.
生物炭添加到土壤中可能会改变土壤的疏水性，并影响土壤水力性质。土壤疏水性，即土壤抗水性（SWR），会阻碍水分入渗并形成优先流，从而导致土壤侵蚀或地下水污染的潜在风险。迄今为止，不同生物炭对土壤疏水性的影响尚不清楚，SWR 与土壤水力性质的关系也尚不清楚。为了将生物炭疏水性与 SWR 和土壤持水能力（WHC）联系起来，本研究对 27 种不同原料和热解温度的生物炭的表面结构和化学成分进行了表征，并研究了生物炭添加土壤的 SWR 和土壤 WHC。生物炭表面的羧基基团、表面积和孔体积主要受热解温度的影响，这表明决定生物炭疏水性严重程度的主要因素是热解温度。生物炭添加后，亲水性土壤变得疏水性。较高的添加率会导致亲水性土壤的 SWR 更强。生物炭添加增加了低总有机碳（TOC）含量亲水性土壤的土壤 WHC。生物炭对高 TOC 含量疏水性土壤的 SWR 和土壤 WHC 没有显著影响。这表明生物炭对 SWR 和土壤水力性质的影响主要取决于土壤原有的疏水性和 TOC 含量。因此，在处理生物炭应用之前，应考虑生物炭的性质及其对土壤疏水性和水力性质的影响。
