Fermented potato fertilizer modulates soil nitrification by shifting the niche of functional microorganisms and increase yield in North China.

Aims: Potato starch wastewater contains higher contents of essential nutrients, which can be fertilizer to help crop growth. However, the effects of fermented potato fertilizer on soil ecology and microbial community structure have not yet been elucidated. This study aimed to investigate the shifts of active ammonia oxidation microbial communities under different fertilization in a typical soil in North China. Methods: The different levels of fermented potato fertilizer without or with chemical fertilizer were designed by field experiment. Results: The results showed that applying fermented potato fertilizer could significantly increase crop yields by 165–399% compared to Control. The content of available soil nutrients and the activity of saccharase and cellulase were increased when fermented potato fertilizer was applied, and the combination fertilizers further increased the content of Olsen-P by 145.6–166.7%, NO₃⁻ by 15.2–81.1%, Total C by 13.8–14%, and Total N by 27.2–34.7% compared with fermented potato fertilizer (PW) treatments. In addition the fermented potato fertilizer significantly stimulated the diversity of soil microbial community and increased the differentiation and stability of soil microbial networks in deep soils. Finally, the change of niche of soil Comammox (COM), ammonia-oxidizing archaea (AOA), and ammonia-oxidizing bacteria (AOB) were found after PW treatments. It showed a significant positive correlation between AOA and COM (r = 0.79, P < 0.01), AOB and NOB (r = 0.7, P < 0.05) instead of theoretically the competitive relationship between AOA and COM. Conclusions: One of the reasons crop yield increase is that fermented potato fertilizer can modulate soil nitrification strategy bychanging the niche of soil functional microorganisms to increase fast-acting nutrients and increase crop yield. [ABSTRACT FROM AUTHOR]