| Abstrakt: |
Continuous cropping obstacles strongly affect yield and soil health during peanut production. The application of Orychophragmus violaceus(AOV) as a green manure is proposed as an alternative to continuous cropping to sustain high yield and soil quality in peanut production systems. However, the mechanisms by which AOV mitigates the obstacles of continuous cropping obstacles in soil through alterations in the soil microbial communities and related functions remain poorly understood. The objective of this study was to investigate the microbiological mechanism by which AOV alleviates the obstacles associated with the continuous cropping of peanut plants. A five-year field experiment was conducted to investigate the responses of soil physicochemical properties, the microbial community and carbon (C), nitrogen (N), phosphorus (P) and sulfur (S) functional genes (as revealed by metagenome shotgun sequencing) to OV amendment. The treatments included continuous peanut cropping as a control (CC) and the application of OV as green manure after peanut harvest. Compared with CC, the AOV treatment significantly increased soil NH4+-N, NO3−-N, available P, exchangeable calcium content and pod yield, while decreased soil pH. Although AOV had a significant negative impact on α-diversity, it increased the abundance of potentially beneficial taxa (e.g., Deinococcus-Thermusphylum and Mycobacteriumgenus) associated with strong resistance to extreme environmental conditions and reduced the relative abundances of pathogens (e.g., Blastocladiomycotaphylum and Fusariumgenus). Comparison of functional genes revealed that AOV enriched the C cycling genes abundance that involved in C fixation and methane metabolism, while decreased the percentage of genes related to C degradation. Furthermore, AOV was beneficial to N cycling genes involved in nitrification and denitrification, while it had the opposite effect on genes related to assimilatory and dissimilatory nitrate reduction. Additionally, AOV stimulated the expression of P cycling genes involved in regulatory, organic P mineralization and transporters. Overall, AOV optimized CNP functional genes and increased the supply of N, P and Ca. Furthermore, AOV stimulated the proliferation of beneficial bacteria while suppressing pathogens. These alterations were likely to have a positive impact on enhancing soil health and mitigating continuous cropping obstacle of peanut. Therefore, peanut-OV rotation is expected to become an alternative to continuous peanut cropping in northern China in the future. |
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