Effects of different cropping systems on bacterial community structure in soil and growth of Amorphophallus konjac

【Objective】To explore the effects of different cropping systems on soil bacterial community structure and growth of Amorphophallus konjac in the next crop，so as to provide scientific basis for improving soil microecological environment by rational cropping systems，and maintaining sustainable planting of A. konjac.【Method】The high-throughput sequencing technology was used to analyze the differences of soil bacterial community structure and diversity under the cropping systems：A. konjac has never been cultivated（N），A. konjac was planted as the previous crop（R），maize was planted for 1 year after A. konjac has been harvested（L1），and maize was planted for 2 years after A. konjac has been harvested（L2）. The effects of soil microecology formed under different planting systems on the growth of A. konjac in the next crop were studied by analyzing the physical and chemical properties of soil before planting A. konjac in the next crop， and the seed germination rate，seedling survival rate，plant height，leaf length，fresh weight of tuber per plant of A. konjac. 【Result】The electrical conductivity，contents of organic matter，alkali hydrolyzed nitrogen，available potassium in the soil sample of R were significantly higher than those in the soil samples of N and L2（P<0.05，the same below）. While pH in the soil sample of R was significantly lower than that in the soil samples of N and L2. The Sobs index，ACE index and Shannon index of soil bacterial communities in the 4 different cropping systems were N>L2>L1>R. Principal coordinates analysis（PCoA）showed that the bacterial community structures of R and L1 treatments were similar，and were both greatly different from those of N and L2 treatments. The relative abundance of Proteobacteria，Myxococcota and Gemmatimonadota in the soil sample of N treatment was significantly higher than that in R treatment，but the relative abundance of Chloroflexi in the soil sample of N treatment was significantly lower than that in R treatment. However，the relative abundance of these 4 dominant bacterial phyla did not differ significantly between N and L2 treatments（P>0.05，the same below）. Correlation analysis showed that soil pH，electrical conductivity，organic matter content，alkali hydrolytic nitrogen content ，available phosphorus content and available potassium content were significantly or extremely significantly （P<0.01，P<0.001）correlated with the relative abundance of dominant bacterial genera in soils such as Bacillus，Gaiella， Solirubrobacter，MND1 and Skermanella. There were no significant differences in the seed germination rate，seedling survival rate，plant height，leaf length and fresh weight of tuber per plant of A. konjac in the next crop between N and L2， and they were both significantly greater than those of R treatment.【Conclusion】The cropping system of maize being planted for 2 years after harvesting A. konjac can restore soil health，promote the growth of A. konjac in the next crop，and effectively alleviate the continuous cropping obstacle of A. konjac by regulating soil microecology.