Effects of different fertilization formulas on fruit quality and soil physical and chemical properties of oil peony in abandoned mining areas

<bold>Objective</bold> The planting area of oil peonies（<italic>Paeonia suffruticosa</italic> Andr.）in China is gradually increasing.However，unreasonable fertilization significantly restricts the improvement of fruit yield and quality of oil peonies，and indiscriminate fertilization can decrease soil fertility.This study aims to explore whether a reasonable fertilization ratio can improve the quality of oil peony fruit and soil properties，thus providing a theoretical basis for the rational planting of oil peony in abandoned mining areas. <bold>Method</bold> The “3414” formula fertilization method was used to fertilize 10-year-old oil peonies according to 14 different nitrogen，phosphorus，and potassium fertilization ratios.The differences in fruit quality and soil physicochemical properties of oil peonies under 14 different treatments were analyzed. <bold>Result</bold> There are significant differences in the effects of different fertilization treatments on fruit quality and soil properties.Suitable nitrogen，phosphorus，and potassium fertilization ratios can significantly improve soil physical and chemical properties，and increase the yield and quality of oil peony seeds.Under the N₃P₂K₂ treatment，most of the indicators，except for the seed shape index，are optimal，especially the quality of oil peony seeds.The number of pods per plant，pod diameter，and seed weight per 100 seeds increase by 106%，31%，and 45%，respectively，compared with those of CK（N₀P₀K₀）.The optimal treatment for soil total nitrogen and alkaline nitrogen was N₃P₂K₂，with total nitrogen increased by 62% compared with that of CK.Although there are differences in soil physical properties among different treatments，the difference is relatively small；N₃P₂K₂ is also the optimal treatment for soil urease and phosphatase，which increase by 33% and 20% respectively compared with that of CK，and the results of the control group treatment are lower than those of other fertilization treatments. <bold>Conclusion</bold> Different fertilization treatments can significantly affect the quality of oil peony fruits and soil properties.The best fertilization result is the N₃P₂K₂ treatment，with recommended fertilization amounts of N：176.8 kg/hm²、P₂O₅：63.1 kg/hm²、K₂O：96.3 kg/hm².