| 摘要 |
[Objectives] This study was conducted to investigate the mechanism of continuous cropping obstacles in Polygonatum odoratum. [Methods] Three treatments were established: continuous cropping (two consecutive crops), first-crop control (with Phaseolus vulgaris as the preceding crop), and blank control. The effects of continuous cropping on the functional diversity of soil microorganisms, soil enzyme activities, and soil nutrient coordination in the rhizosphere soil of P. odoratum during different growth stages were investigated. [Results] (1) Continuous cropping increased the carbon source metabolic capacity, Shannon diversity index, and richness of rhizosphere soil microorganisms by 3.2%-14.7%, 0.9%-3.5%, and 1.3%-12.5%, respectively, but the differences were not significant. (2) Principal component analysis indicated that during the middle stage of rhizome expansion, continuous cropping significantly altered the characteristics of microbial carbon metabolism, and the microbial communities utilizing carbohydrates, amino acids, polymers, carboxylic acids and amines as carbon sources exhibited vigorous metabolism. (3) Continuous cropping significantly reduced the activities of urease, polyphenol oxidase, and acid phosphatase in rhizosphere soil, with decreases of 24.4%-39.5%, 3.2%-14.8%, and 7.9%-18.2%, respectively. The activities of catalase and invertase sometimes exceeded and sometimes fell below those of the first crop, showing no consistent pattern. (4) Under continuous cropping conditions, nutrient imbalance occurred in the rhizosphere soil, characterized by nitrogen deficiency and phosphorus surplus. (5) Grey correlation analysis indicated that available phosphorus content, alkali-hydrolyzable nitrogen content and polyphenol oxidase activity in rhizosphere soil were the main factors influencing microbial functional diversity. [Conclusions] This study provides a theoretical basis for understanding the formation mechanism of continuous cropping obstacles in P. odoratum. |
