The effect of slow-release phosphate fertilizers from digestates on maize rhizosphere soil microbial community and nutrient cycling: Response and activation mechanism

• Published in: Applied soil ecology : a section of Agriculture, ecosystems & environment ecosystems & environment, 2024-09, Vol.201, p.105528, Article 105528
• Main Authors: Li, Bowen, Zhao, Nan, Ran, Xueling, Zheng, Yonghui, Sobhi, Mostafa, Dong, Renjie, Guo, Jianbin
• Format: Article
• Language: English
• Subjects: Anaerobic digestion; Fertilizer; Hydroxyapatite; Maize–soil system; Phosphate-solubilizing microorganisms; Struvite
• ISSN: 0929-1393; 1873-0272
• DOI: 10.1016/j.apsoil.2024.105528

Anaerobic digestion (AD) constitutes an efficient technological approach for reducing waste and generating nutrient-rich digestates, which can effectively facilitate the recycling of phosphorus (P). P compounds such as CaP and MgP undergo mineralization during AD and then transform into insoluble P, which subsequently precipitates within the solid phase of the digestate. However, the effectiveness of these insoluble phosphates, especially CaP, and the response of plants and organisms to insoluble P remain unclear. Thus, this study aimed to investigate the effects of struvite (MAP) and hydroxyapatite (HAP), two typical insoluble phosphates from digestates, on maize growth and rhizospheric microorganisms in a maize–soil system. Results showed that the maize yields in the MAP and HAP groups were 13.00 % and 19.26 % higher, respectively, than that in the control group and 13.65 % and 8.87 % lower, respectively, than that in the superphosphate (SSP) group. Similar results were obtained for the shoot nutrients. The fertilizer utilization efficiencies were approximately 18.9 % in the SSP group, 9.6 % in the MAP group, and 12.1 % in the HAP group. Maize in the MAP and HAP groups absorbed more P from deeper soil as a supplement, displaying adaptability to low P environments. Moreover, P-solubilizing microorganisms (PSMs), such as Bacillus sp., Gaiellales sp., and Fusarium sp., were enriched in the black control (CK), MAP, and HAP groups and played important roles in mineralizing and dissolving P. In conclusion, MAP and HAP can be used as potential P fertilizer supplements and can be further developed by strengthening PSMs in fertilizers. This study provides theoretical support for utilizing non-water soluble P in digestates and novel insights into the development of new P fertilizers. [Display omitted] •Struvite and hydroxyapatite played a role in maize growth.•Maize yield in MAP and HAP groups was 13.65 % and 8.87 % lower than SSP.•PSMs responded to the low rapid P environments and activated non-available P.•Struvite and hydroxyapatite can be used as a potential P fertilizer supplement.