Water and fertilizer management regulates soil quality, bacterial community structure and function, and yield in Panax Notoginseng

Abstract Background Proper water and fertilizer management can improve soil quality, regulate soil microbial community balance, and increase crop yield. However, the overall soil quality of Panax notoginseng under different irrigation and fertilization levels are still unclear. Methods We set up an experiment with W1F1, W1F2, W1F3, W1F4, W2F1, W2F2, W2F3, W2F4, W3F1, W3F2, W3F3, W3F4 irrigation and fertilization treatments and a non-irrigated and non-fertilized CK as a control in Panax pseudoginseng farmland during 3 consecutive years. The differences of TDS covering 13 soil physicochemical properties and biological indicators in the fruiting stage of Panax notoginseng under different irrigation and fertilization treatments were analyzed, and the effects of different irrigation and fertilization treatments on the structure and function of soil bacterial community in a phyla level were further explored. The soil MDS was selected by principal component analysis and Norm value combined with Pearson correlation analysis, and the SQI-MDS was employed to comprehensively evaluate the soil quality of Panax notoginseng under each irrigation and fertilization treatment and the corresponding yield was associated. Results The data showed that the soil physicochemical properties and Alpha diversity index, structure, and function of bacterial in Panax notoginseng under different irrigation and fertilization treatments in three years had significant difference. In 3 years, the coupling water and fertilizer treatments compared to single fertilization or irrigation had more unique bacteria phyla, the Acidobacteriota, Actinobacteriota, Chloroflexi, and Proteobacteria were the dominant bacteria phyla in each fertilization or irrigation treatment, the Acidobacteriota and Firmicutes phylum demonstrated significant difference in the W3 and F3 treatment, respectively, and the values of multiple positive soil physicochemical indicators and bacterial functional metabolism potential under the W3F3 treatment were significantly greater than CK. In addition, the functional richness of soil beneficial bacteria in Panax notoginseng increased with the increased planting years. The soil MDS included pH and Shanno indicators, and the fitting effect between SQI-MDS-NL and SQI-TDS were better in each year. The irrigation and fertilization regimes under the top three soil quality were the same and the soil quality under the W3F3 treatment was in the top three in every year. Furthermore, the yield in Panax notoginseng under the W3F3 treatment in 2018–2019, 2019–2020, and 2021–2022 year increased by 1.63 times, 1.29 times, and 0.95 times compared with CK, respectively. Conclusions This study provides a reference for understanding the overall soil condition of Panax notoginseng under different irrigation and fertilization regimes in the long term and formulating the optimization plan of irrigation and fertilization management increasing the yield in Panax notoginseng.