Long-term continuous cropping induced phenolic acid accumulation, acidification and microbial deterioration in greenhouse-based strawberry soil

Continuous cropping (CC) can trigger drastic variations in the microenvironment of farmland soil, resulting in the development of persistent soil-borne diseases. However, the integrated influences of long-term CC on the abiotic and biotic factors of the strawberry soil have not been sufficiently characterized. In this study, variations in physico-chemical characteristics, enzymatic activities, phenolic acids and microorganisms were investigated in long-term strawberry CC soil. The results demonstrated a continuous decrease in soil pH and a first increase and then decrease in soil enzyme activities. Additionally, phenolic acid concentrations were found to accumulate. CC for 15 and 18 years resulted in a significant decrease microbial diversity, relative abundance, and the ratio of bacteria to fungi in soil. Specifically, bacterial Bacillus (Top2 genus) increased considerably in the two and five years, while fungal Fusarium (Top2 genus) decreased in the fifteen and eighteen years. Moreover, the structural equation model (SEM) provided a comprehensive insight into the effects of strawberry CC on soil conditions. The SEM revealed that the standardized regression coefficients of CC on enzyme activity, phenolic acid, bacterial and fungal communities were 0.86, 0.95, -0.39, and 0.17, respectively. In conclusion, the findings contribute to a deeper knowledge of the challenges posed by CC and provide insights for future research and agricultural management practices.