The system elucidates the functions and mechanisms of green manure in cultivating healthy soil, which clarifies the irreplaceability of green manure and its critical role in leading green agriculture in the new era. Recently, the green manure group from the Innovation Team of Fertilizer and Fertilization Technology of the Institute of Agricultural Resources and Regional Planning (IARRP) of the Chinese Academy of Agricultural Sciences (CAAS) made a series of discoveries in the cultivation of healthy soil in the arid region of northwest China, which were published in the journals "SCIENCE CHINA Life Sciences" and "iMeta".

The study found that long-term planting and utilization of green manure can recruit diazotrophs and arbuscular mycorrhizal fungi (mainly enhancing Azospirillum and Glomus), while also strengthening the synergistic relationship between diazotrophs and arbuscular mycorrhizal fungi in the co-occurrence network formed by key ecological clusters (dominated by Skermanella, Azospirillum and Glomus). It significantly enhanced the soil's potential for endogenous nitrogen fixation. Further research showed that long-term planting and utilization of green manure produced  wheat yields equivalent to those obtained with chemical fertilizers alone, primarily by improving soil nitrogen cycling functions (especially soil nitrogen mineralization and biological nitrogen fixation) to meet the nutrient requirements of wheat production. Furthermore, the soil under green manure application exhibited higher multifunctionality. Soils treated with long-term chemical fertilizers, green manure, and cow manure resulted in the highest abundances of amoB, nifH, and GH48 genes and Nitrosomonadaceae, Azospirillaceae, and Sphingomonadaceae within the keystone phylotypes, and these microbes were significantly and positively correlated with N₂O release, N fixation, and organic C mineralization, respectively. Organic fertilizer application methods, especially green manure, drove the migration of soil microorganisms across the soil profiles, increased the size, abundance, and biodiversity of key microbial groups in subsoil microbial networks, thereby enhancing the multifunctionality of subsoil. However, the application of cow manure and straw residue to the soil reduced the stability of the soil microbial network. This research provides a theoretical basis for using green manure to build nutrient-efficient cycling systems and to selectively regulate soil microbial communities to cultivate healthy soil.

Dr. Zhou Guopeng, a postdoctoral researcher at the IARRP is the first author of the paper. The corresponding authors are Dr. Cao Weidong from the same institute and Dr. Che Zongxian from the Institute of Soil Fertilizer and Water-saving Agriculture, Gansu Academy of Agricultural Sciences. The research were jointly funded by the National Key Research and Development Program (2021YFD1700200) and the National Green Manure Industrial Technology System (CARS-22) project.

Link to the paper:

http://engine.scichina.com/doi/10.1007/s11427-023-2432-9 

https://doi.org/10.1002/imt2.81