Engineered biochar-attapulgite clay composite: A novel slow-release phosphorus fertilizer

作者：Harleen Kaur, Gurwinder Singh, Marjana Yeasmin, Kavitha Ramadass, Puspamitra Panigrahi, Alan Larson, Ranjit Pati, Dane Lamb, Bo Zheng, Ehsan Tavakkoli, Lukas Van Zwieten, Ajayan Vinu · 发表于：Chemical Engineering Journal · 年份：2025 · DOI：10.1016/j.cej.2025.165791 · 被引用次数：26 · 研究领域：Phosphorus and nutrient management、Clay minerals and soil interactions、Polymer-Based Agricultural Enhancements

Sustainable agricultural practices are in high demand, and the development of innovative materials for slow nutrient release holds utmost importance. Phosphorus (P) stratification limits plant P availability in no-till farming systems. To address this, a nano composite-based P fertilizer to release nutrients in the root zone following surface soil application is constructed. The nanocomposite fertilizers (BAP-SRFs) were formed by a combination of different amounts of biochar (BC), attapulgite clay (ATP) and KH 2 PO 4 , followed by a high-temperature treatment (500 °C). XANES analysis revealed the enrichment of the surface with carbon (C), oxygen (O) and P-containing functional groups, and the bond formation of P with calcium (Ca) and magnesium (Mg) and organic C. Batch desorption and dynamic release experiments provided conclusive evidence that an interplay between ATP and P contents is crucial for the optimum delivery of P in both aqueous and soil media. The slowest release of P in water was achieved in BAP-SRF, which had a BC to ATP ratio of 2 and was loaded with 200 mg of KH 2 PO 4 . Pseudo-second-order kinetics presented the best fit for P release, demonstrating that the release mechanism of P is primarily based on diffusion. The visual diffusion of P in soil provides critical evidence of the slow-release nature of the BAP-SRFs as compared to commercial single super phosphate. The experimental findings were further corroborated by the first principles density functional t...