Short-term continuous monocropping reduces Curcuma kwangsiensis yield mainly via altering soil pH and Microbial community

Abstract Pursose In order to investigate the effects of short-term continuous monocropping on rhizosphere soil of Curcuma kwangsiensis (C. kwangsiensis) and establish a theoretical foundation for the conservation of the soil ecological environment as well as the future sustainable development of the C. kwangsiensis cultivation industry. Methods This study examined how short-term continuous monocropping affected the physicochemical characteristics, enzyme activities and microbial community of the rhizosphere soil of C. kwangsiensis. Rhizosphere soil samples were taken from C. kwangsiensis that had been planted for 1 (Y1) and 2 years (Y2). The soil before planting was used as the control (Y0). The microbial community structure in the rhizosphere soil was studied using a high-throughput analysis. Results The results showed that the yield of C. kwangsiensis in Y2 was 58.38% of that in Y1. The soil pH decreased; soil nutrients accumulated, and the activities of soil enzymes increased initially and then decreased with continuous cropping. Continuous cropping produced a relatively high abundance and diversity of bacterial and fungal species. Continuous cropping resulted in a significantly higher relative abundance of Planctomycetota as the dominant bacterial phylum, while the relative abundances of Ciliophora and Cercozoa as the dominant fungal phyla were also significantly higher. The pH was the most important factor that affected the microbial community composition. Conclusion The continuous monocropping of C. kwangsiensis reduced the soil pH and altered the physicochemical properties and activities of enzymes in the soil, which resulted in a decrease in the proportion of bacteria. This finding explains the decline in C. kwangsiensis production and provides a potential remedy for growers.