School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China.
Jiangsu Key Laboratory of Environmental Functional Materials, School of Chemistry Biology and Material Engineering, Suzhou University of Science and Technology, Suzhou, 215009, China.
Environ Pollut. 2018 Aug;239:562-570. doi: 10.1016/j.envpol.2018.04.050. Epub 2018 Apr 23.
Land application of biomass-derived biochar has been increasingly recommended as a beneficial soil amendment for nutrients (such as N, P) retention. However, the small-scale biochar particles, especially those in the nano-scale range, may carry nutrients downward the soil profile, reducing nutrition retention and posing a potential risk to the groundwater. In this study, column experiments were conducted to investigate the retention and transport of phosphorus (P) in two acidic and two alkaline soils as affected by wood chip-derived biochar nanoparticles (NPs). In acidic paddy and red soils, biochar NPs facilitated the retention of P, increasing by about 24% and 16%, respectively, compared to the biochar absence. It is because biochar NPs stabilize soil Fe/Al oxides and dissolved organic carbon (DOC), thereby reducing the release of Fe/Al oxides- and DOC-associated P. In contrast, in alkaline huangmian and chao soils, retention of P was reduced in the presence of biochar NPs, decreasing by about 23% and 18%, respectively. It was mainly due to the increased transport of Fe/Al oxides-associated P in effluents. Moreover, biochar NPs could also act as a P carrier, mediating the retention of P. The diffusive gradients in thin films provided in-suit measurement of labile P in soil profiles, showing much lower labile P from retained P in acidic soils than that from alkaline soils though the labile P with biochar NPs presence was increased in all soils. Our findings indicate that biochar NPs have contrasting effects on the retention of P in acidic and alkaline soils, implying the cautious land applications of biochar for nutrients retention in soils with different acidities.
生物炭作为一种有益的土壤改良剂，被越来越多地推荐用于养分（如 N、P）的保持。然而，小规模的生物炭颗粒，尤其是纳米级范围内的颗粒，可能会携带养分向下迁移到土壤剖面中，减少营养物质的保持，并对地下水构成潜在风险。在这项研究中，进行了柱实验，以研究木屑衍生的生物炭纳米颗粒（NPs）对两种酸性和两种碱性土壤中磷（P）的保留和迁移的影响。在酸性稻田和红壤中，生物炭 NPs 促进了 P 的保留，与无生物炭存在相比，分别增加了约 24%和 16%。这是因为生物炭 NPs 稳定了土壤 Fe/Al 氧化物和溶解有机碳（DOC），从而减少了 Fe/Al 氧化物和 DOC 相关 P 的释放。相比之下，在碱性黄绵土和潮土中，生物炭 NPs 的存在减少了 P 的保留，分别减少了约 23%和 18%。这主要是由于流出物中 Fe/Al 氧化物相关 P 的迁移增加所致。此外，生物炭 NPs 还可以作为 P 的载体，介导 P 的保留。薄膜扩散梯度提供了土壤剖面中可利用 P 的原位测量，表明酸性土壤中保留的 P 比碱性土壤中的可利用 P 低得多，尽管所有土壤中的可利用 P 都因生物炭 NPs 的存在而增加。我们的研究结果表明，生物炭 NPs 对酸性和碱性土壤中 P 的保留具有相反的影响，这意味着在不同酸度的土壤中谨慎地应用生物炭来保持养分。
