School of Agriculture, Sun Yat-sen University, Shenzhen, Guangdong 518107, China; Modern Agricultural Innovation Center, Henan Institute of Sun Yat-sen University, China.
Vegetable Research Institute, Guangdong Academy of Agricultural Sciences, Guangzhou, 510640, China.
Sci Total Environ. 2022 Oct 15;843:157037. doi: 10.1016/j.scitotenv.2022.157037. Epub 2022 Jun 28.
Biochar (BC) as a increasing widely adopted soil amendments showed potential threat to soil P leaching, but the relevant mechanisms were not clear enough and relevant strategy should be proposed to address the P leaching induced by BC application. In this study, effects of ordinary corn straw BC, and a fabricated Mg/Al-LDHs modified biochar (LBC) on soil P availability, adsorption, fraction and mobility were compared and investigated by conducting the column and incubation experiments at biochar to soil rate of 1 %, 2 % and 4 % (w/w). Chemical sequential extraction methods and various solid-state method (i.e., three-dimensional excitation emission matrix (EEM), x-ray diffraction (XRD), scanning electron micrograph (SEM) and P K-edge X-ray absorption near edge structure (XANES)) were utilized to give deep insights into the P mobilization and immobilization mechanisms by respectively applying the BC and LBC. Results of incubation experiments showed that applying the LBC reduced the labile P with significant CaP transformation to Al-retained P, while ordinary BC promoted the Fe/Al-P transformation to labile dibasic calcium phosphate and monobasic calcium phosphate evidenced by the EEM analysis, in-situ XANES investigation and chemical sequential extraction methods. Results of phosphatase and microbial analyses indicated that the decreased labile P after 30 days' incubation and the mitigated P leaching in LBC treatment were dominantly ascribed to abiotic processes of inorganic P transformation and (de)sorption. This research gave deep insights into abiotic and biotic processes of ordinary biochar promoting soil P leaching, and important implications for applying engineered biochar in reducing P leaching and improving soil productivity.
生物炭（BC）作为一种越来越广泛应用的土壤改良剂，对土壤磷淋失表现出潜在威胁，但相关机制尚不清楚，应提出相关策略来解决生物炭应用引起的磷淋失问题。在这项研究中，通过在生物炭与土壤的比例为 1%、2%和 4%（w/w）的柱和培养实验，比较和研究了普通玉米秸秆生物炭和一种制备的 Mg/Al-LDHs 改性生物炭（LBC）对土壤磷有效性、吸附、形态和迁移性的影响。采用化学连续提取方法和各种固态方法（即三维激发发射矩阵（EEM）、X 射线衍射（XRD）、扫描电子显微镜（SEM）和 P K 边 X 射线吸收近边结构（XANES）），深入研究了分别施加 BC 和 LBC 时磷的活化和固定化机制。培养实验结果表明，施加 LBC 减少了可利用磷，同时将大量 CaP 转化为 Al 保留磷，而普通 BC 则促进了 Fe/Al-P 向可利用的二碱式磷酸钙和一碱式磷酸钙的转化，这可以通过 EEM 分析、原位 XANES 研究和化学连续提取方法得到证实。磷酸酶和微生物分析结果表明，经过 30 天培养后可利用磷减少，LBC 处理中磷淋失减轻，主要归因于无机磷转化和（脱）吸附的非生物过程。这项研究深入了解了普通生物炭促进土壤磷淋失的非生物和生物过程，为应用工程生物炭减少磷淋失和提高土壤生产力提供了重要启示。
