College of Hydraulic Science and Engineering, Yangzhou University, Yangzhou, Jiangsu 225009, China.
College of Water Resource, Shenyang Agricultural University, Shenyang, Liaoning 110866, China.
Sci Total Environ. 2024 Oct 20;948:174956. doi: 10.1016/j.scitotenv.2024.174956. Epub 2024 Jul 24.
Biochar exhibits numerous advantages in enhancing the soil environment despite a few limitations due to its lower surface energy. Nanomodified biochar combines the advantages of biochar and nanoscale materials. However, its effects on water infiltration and N leaching in a clayey soil remain unclear. Therefore, this study prepared rice straw nano-biochar by a ball milling method, and investigated its physicochemical properties and effects of bulk biochar and nano-biochar at various addition rates (0 %, 0.5 %, 1 %, 2 %, 3 %, and 5 %) on wetting peak migration, cumulative infiltration, water absorption and retention, and N leaching. The results showed that, compared with bulk biochar, nano-biochar presented a more abundant pore structure with an increase in specific surface area of approximately 1.5 times, accompanied by a 20 % increase in acid functional groups. Compared with those for clayey soil without biochar addition, the wetting front migration time was increased by 10.2 %-123.9 % and 17.0 %-257.9 %, and the cumulative infiltration volume at 60 min was decreased by 26.0 %-48.4 % and 14.1 %-62.4 % for bulk biochar and nano-biochar, respectively. The parameter S of Philip model and the parameter a of Kostiakov model for nano-biochar were lower than those for bulk biochar, whereas the parameter b of Kostiakov model was greater, indicating that nano-biochar decreased initial soil infiltration rate and increased attenuation degree of the infiltration rate. Nano-biochar increased water absorption by 8.03 % and subsequently enhanced water retention capacity relative to bulk biochar. In addition, bulk biochar and nano-biochar reduced NH-N leaching by 3.0 %-13.1 % and 5.7 %-39.2 %, respectively, and NO-N leaching by 2.7 %-3.6 % and 9.0 %-43.3 %, respectively, by decreasing N concentration and leachate volume relative to those with no biochar addition. This study provides new knowledge for nano-biochar application in a clayey soil.
生物炭在增强土壤环境方面表现出许多优势，尽管由于其表面能较低而存在一些局限性。纳米改性生物炭结合了生物炭和纳米材料的优势。然而，其对粘性土壤中水分入渗和氮淋失的影响尚不清楚。因此，本研究采用球磨法制备水稻秸秆纳米生物炭，研究了不同添加率（0%、0.5%、1%、2%、3%和 5%）下大比表面积生物炭和纳米生物炭对润湿峰迁移、累积入渗、水分吸收和保持以及氮淋失的影响。结果表明，与大比表面积生物炭相比，纳米生物炭具有更丰富的孔结构，比表面积增加了约 1.5 倍，同时酸性官能团增加了 20%。与未添加生物炭的粘性土壤相比，润湿前沿迁移时间分别增加了 10.2%-123.9%和 17.0%-257.9%，60min 累积入渗体积分别减少了 26.0%-48.4%和 14.1%-62.4%，大比表面积生物炭和纳米生物炭的菲利普模型参数 S 和科斯蒂亚科夫模型参数 a 均低于大比表面积生物炭，而科斯蒂亚科夫模型参数 b 则大于大比表面积生物炭，表明纳米生物炭降低了初始土壤入渗率，增加了入渗率衰减程度。纳米生物炭增加了 8.03%的水分吸收，从而增强了相对于大比表面积生物炭的水分保持能力。此外，大比表面积生物炭和纳米生物炭分别减少了 3.0%-13.1%和 5.7%-39.2%的 NH-N 淋失和 2.7%-3.6%和 9.0%-43.3%的 NO-N 淋失，与不添加生物炭相比，降低了 N 浓度和淋出液体积。本研究为纳米生物炭在粘性土壤中的应用提供了新的知识。
