In the quest for sustainable agriculture, straw returning—a practice where crop residues are plowed back into the soil—has emerged as a promising strategy to enhance soil health and reduce environmental impact. However, the comprehensive effects of this practice on soil microbial communities and their functions remain underexplored. A recent study published in *Zhejiang University Journal: Agricultural and Life Sciences Edition* sheds light on this critical gap, offering insights that could reshape agricultural and energy sector practices.
Led by WANG Binhao, the research delves into the long-term impacts of straw returning on various functional genes and microbial taxa in paddy fields. By analyzing soil samples from Ningbo City, Zhejiang Province, where straw has been returned for over five years, the study employed high-throughput metagenomic sequencing to assess changes in antibiotic resistance genes (ARGs), methane-cycling genes (MCGs), nitrogen-cycling genes (NCGs), and virulence factor genes (VFGs).
The findings reveal a nuanced picture. Long-term straw returning significantly decreased the richness of nitrogen-cycling genes and virulence factor genes, as well as the abundance of key methanogenesis genes like mcrA, B, C, and G. “This suggests that straw returning could potentially reduce greenhouse gas emissions, particularly methane and nitrous oxide, from rice fields,” WANG Binhao noted. The study also found a reduction in the abundance of the methanogenesis taxon Methanosarcina mazei and genes related to methylotrophic methanogenesis, further supporting this hypothesis.
However, the practice is not without its trade-offs. The research highlighted a significant increase in the abundance of virulence factor genes under long-term straw returning, indicating a heightened risk of rice diseases. “While straw returning offers environmental benefits, it also poses challenges for disease management in agriculture,” WANG Binhao explained.
The study also explored the relationship between soil chemical properties and microbial functional group composition. Multiple regression on distance matrix analysis revealed that total organic carbon and dissolved organic carbon were closely linked to the soil microbial functional group composition, underscoring the importance of these factors in shaping soil ecology.
For the energy sector, these findings are particularly relevant. The reduction in methane and nitrous oxide emissions could contribute to lower greenhouse gas footprints, aligning with global efforts to combat climate change. “Understanding the microbial dynamics in soil can help us develop more effective strategies for carbon sequestration and greenhouse gas mitigation,” WANG Binhao added.
As agriculture continues to evolve, the balance between sustainability and productivity remains a critical challenge. This research underscores the need for a holistic approach to soil management, one that considers both the ecological and commercial impacts. By integrating these findings into agricultural practices, stakeholders can work towards a more sustainable and resilient future.
Published in *Zhejiang University Journal: Agricultural and Life Sciences Edition*, this study provides a foundation for further exploration into the complex interplay between straw returning, soil microbial communities, and environmental health. As the agricultural and energy sectors continue to innovate, such research will be instrumental in guiding policy and practice towards a greener, more sustainable future.