Effects of different amendment treatments on survival rate and soil microbial community of continuous cropping Atractylodes macrocephala.

Prolonged continuous cropping of Atractylodes macrocephala usually cause soil-borne diseases such as root rot, resulting in significant yield losses even total crop failure. Burning, fumigation, and microbial inoculant application are commonly used to suppress soil-borne diseases in agricultural systems. However, their effects on plant performance and soil microbial communities in continuously cropped A. macrocephala systems remain poorly understood. We conducted a field experiment with high-throughput amplicon sequencing to examine the effects of burning, soil fumigation, microbial inoculant application, and their combined treatment (burning + fumigation + microbial inoculant application) on the survival rate, yield, and soil microbial communities of continuously cropped A. macrocephala, as well as to identify the key microbial taxa influencing A. macrocephala survival. The results showed that all soil amendment treatments increased A. macrocephala survival rate and yield. Soil fumigation treatment had the strongest effect on plant survival, with a survival rate of 66.9% and a yield of 2533.46 kg·hm-2, representing 89.5% and 157.8% increases, respectively. The combined treatment of soil burning, fumigation, and microbial inoculant application resulted in a survival rate of 61.1% and a yield of 2749.52 kg·hm-2, correspon-ding to 73.1% and 179.8% increases, respectively, and showed the largest yield gain among all treatments. Soil fungal community composition differed significantly among treatments, whereas bacterial community structure exhi-bited comparatively limited variation. Soil fungal communities in the control were dominated by Basidiomycota, whereas Ascomycota predominated in soils subjected to burning, fumigation, microbial inoculant application and the combined treatment. The combined treatment harbored the most connected fungal network, with 14204 edges, and exhibited a smaller decline in network stability following the removal of keystone nodes, indicating enhanced network complexity and robustness. Random forest analysis identified Leptosphaerulina, Saitozyma, Paraboeremia, and Fusarium as the key fungal genera associated with A. macrocephala survival, with their relative abundances being significantly reduced under fumigation and the combined treatments. The survival rate of A. macrocephala was negatively correlated with the relative abundances of Saitozyma (R2=0.32). Together, these findings indicate that soil fumigation and the combined application of soil burning, fumigation, and microbial inoculants can improve the ecological function of continuously cropped soils by restructuring soil microbial communities, enhancing fungal network stability and suppressing putative fungal pathogens, thereby increasing the survival rate and yield of A. macrocephala.