Nanozeolite-Coupled Biochar-Based Controlled-Release Phosphorus Fertilizer: Performance, Release Mechanism, and Techno-Economic Analysis
Chang‐Zhi Dong, Cheng Yang, Mengqiao Wu, Qian Wang, Yan Zhang, Jason C. White, Hai Xiang, Yanjiang Cai, Yongfu Li, Bing Yu
Abstract
Phosphorus fertilization is critical for crop production; however, traditional chemical phosphorus fertilizers (Chem-P) are highly inefficient, which leads to nutrient loss and environmental pollution. Here, a new nanozeolite-coupled biochar-based phosphorus fertilizer (ZEO/BC-PSRF) was developed using a simple disc granulation process, with kaolinite serving as a binder. The controlled-release performance of this fertilizer was evaluated through water release testing, where ZEO/BC-PSRF demonstrated the slowest phosphorus release, with only 29.4% being released after 24 h, compared with 43.8% for BC-PSRF (without nanozeolite) and 54.3% for Chem-P. Additionally, ZEO/BC-PSRF exhibited the best controlled-release performance in column leaching tests, with a cumulative P release rate reaching 23.4% after 42 days. A greenhouse pot experiment with tomato demonstrated that ZEO/BC-PSRF significantly enhanced seedling growth and increased the levels of vitamin C and lycopene in the harvested fruits compared with the BC-PSRF and Chem-P treatments. Mechanistic investigations suggest that the primary mechanism for the controlled release of phosphorus from ZEO/BC-PSRF is the enhanced adsorption of phosphorus onto the ZEO/BC. Further, ZEO/BC-PSRF maintained the highest available soil phosphorus content, promoting the growth of phosphorus-utilizing soil bacteria and facilitating enhanced phosphorus uptake by tomato. An economic feasibility analysis confirmed the potential for cost-effective large-scale production, while a comparison of carbon emissions indicated that the application of ZEO/BC-PSRF had the capacity to reduce greenhouse gas emissions in contrast to traditional Chem-P. This study highlights the potential of combining biochar and zeolite as a sustainable and low-cost solution to enhance the efficacy of phosphorus fertilizers in agricultural production while simultaneously reducing carbon emissions.