Changes in rhizosphere microbial community of potato under farmland with different cultivation years in alpine-cold...

Soil quality and microbial community structure are highly responsive to tillage practices, with long-term tillage leading to soil degradation and shifts in the rhizosphere microbial community. However, the mechanisms through which tillage duration and soil quality influence the potato rhizosphere microbial community in the black soil regions of alpine areas remain poorly understood.

To address this, farmlands with varying tillage durations (0, 5, 20, and 60 years) were selected. The space-for-time substitution method was employed to investigate the dynamic variations and functions of the potato rhizosphere microbial community across these different tillage durations, aiming to elucidate microbial succession patterns under prolonged conventional tillage.

The results revealed that long-term tillage significantly altered soil nutrient content. The Chao and Shannon indices for bacteria varied in response to changes in soil nutrients, whereas those for fungi declined with increasing tillage duration and eventually stabilized. Soil alkaline nitrogen (AN), total nitrogen (TN), total phosphorus (TP), and organic matter (SOM) content were positively correlated with the beneficial bacterial community. Distinct differences in bacterial biomarker taxa were observed across tillage durations, while the number of fungal biomarker taxa sharply decreased with extended tillage. Long-term tillage notably increased the abundance of aerobic chemoheterotrophic bacteria, ureolytic bacteria, organic matter-decomposing bacteria, fungal plant pathogens, and endophytic fungi. Partial least-squares analysis indicated that tillage duration and soil factors collectively explained 72% of bacterial diversity and 54% of its compositional variation, as well as 54% of fungal diversity and 72% of its compositional variation. Both factors exerted direct and indirect regulatory effects on the microbial community.

In summary, long-term tillage had a direct impact on the rhizosphere microbial community and its functional potential, with bacteria being more sensitive to long-term tillage than fungi. Thus, in the development of the potato industry in the black soil regions of alpine areas, maintaining and improving soil fertility and quality should be prioritized.