Nano molybdenum trioxide-mediated enhancement of soybean yield through improvement of rhizosphere soil molybdenum bioavailability for nitrogen-fixing microbial recruitment

• Published in: The Science of the total environment Vol. 937; p. 173304
• Main Authors: Li, Qibiao, Huang, Kan, Liu, Zhichen, Qin, Xiaoming, Liu, Yining, Tan, Qiling, Hu, Chengxiao, Sun, Xuecheng
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 10.08.2024
• Subjects: Available Mo; MoO3 NPs; Nitrogen-fixing bacteria; Rhizosphere soil; Soybean; Available Mo; Nitrogen-fixing bacteria; Soybean; MoO3 NPs; Rhizosphere soil; MoO NPs
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2024.173304

Molybdenum (Mo) plays a pivotal role in the growth and nitrogen-fixing process of plants mediated by rhizobia. However, the influence of nano‑molybdenum trioxide (MoO3NPs) on soybean growth, rhizosphere bioavailable Mo, and nitrogen-fixing microorganisms remains underexplored. Here, we report that compared with that of ionic Mo and bulk MoO3, the utilization of MoO3NPs (specifically NPs0.05 and NPs0.15) significantly boosted the available Mo content in the rhizosphere soil throughout the seedling (by 21.64 %–101.38 %), podding (by 54.44 %–68.89 %), and mature stage (by 34.41 %–to 45.71 %) of soybean growth. Furthermore, both NPs0.05 and NPs0.15 treatments maintained consistently higher levels of acid-extractable Mo, reducible Mo, and oxidizable Mo across these stages, which facilitated stable conversion and supply of bioavailable Mo. Within the rhizosphere soil, NPs0.05 and NPs0.15 treatments resulted in the highest relative abundance of Rhizobiales and Bradyrhizobium genera, and significantly promoted the colonization of nitrogen-fixing microorganisms, thereby increasing the content of nitrate nitrogen (NO3−-N) by 8.69 % and 7.72 % and ammonium nitrogen (NH4+-N) by 44.75 % and 17.55 %, respectively. Ultimately, these effects together contributed to 107.17 % and 84.00 % increment in soybean yield by NPs0.05 and NPs0.15 treatments, respectively. In summary, our findings underscore the potential of employing MoO3NPs to promote plant growth and maintain soil nitrogen cycling, indicating distinct advantages of MoO3NPs over ionic Mo and bulk MoO3. [Display omitted] •MoO3 NPs increased the available Mo during different growth stages of soybeans.•NPs0.05 maintained high levels of biologically available Mo, ensuring a stable supply of throughout the growth stages.•NPs0.05 enhanced the recruitment and function of nitrogen-fixing microorganisms.•Nitrogen-fixing microorganisms recruitment increased NO3‐−N and NH4+-N in the rhizosphere, boosting soybean yield by 124%.