Microbial-driven nitrogen retention in optimized shelter forests: A solution for agricultural non-point source...

Area of Science:

• Environmental Science
• Soil Science
• Microbiology

Background:

• Agricultural nonpoint source pollution (NPSP) is a global environmental issue, with soil nitrogen (N) loss contributing to eutrophication.
• Soil microorganisms play a critical role in regulating soil N dynamics, making microbial community structure a potential target for N loss control.

Purpose of the Study:

• To investigate the impact of transforming pure moso bamboo forests into swell-structured water source shelter forests (WWSSFs) on soil microbial communities and nitrogen (N) loss.
• To elucidate the mechanisms by which forest structure optimization influences microbial communities and mitigates N loss.

Main Methods:

• Conducted in situ investigations comparing pure moso bamboo stands with two types of WWSSFs.
• Analyzed shifts in microbial community structure and quantified total-N and nitrate-N loss.
• Utilized partial least squares path modeling to determine direct and indirect effects of forest structure on N loss via microbial mediation.

Main Results:

• WWSSFs exhibited significant shifts in microbial community structure compared to pure bamboo stands.
• WWSSFs reduced total-N loss by 62.48%-71.45% and nitrate-N loss by 31.78%-64.61%.
• Microbial communities mediated N loss reduction through pathways involving changes in specific bacteria (e.g., Bradyrhizobium, Candidatus Nitrosotalea) and decreased soil nitrification.

Conclusions:

• Strategically restructuring vegetation to create WWSSFs is an effective method for mitigating agricultural NPSP.
• The study highlights the crucial role of microbial communities in mediating the reduction of N loss through ecological engineering.
• WWSSFs offer a scientifically validated approach for sustainable watershed management by reinforcing biological regulatory mechanisms.