Study On The Effect Of Different Fertilizers On Relieving Stevia Continuous Cropping Obstacles

With the continuous exploitation of stevia’s utilization value,the market demand for stevia is also increasing,resulting in the increasingly serious stevia continuous cropping phenomenon,the problem of continuous cropping obstacles to be solved urgently.In this study,the effects of different fertilizers on the agronomic character,physiological index,glycoside content,physical and chemical character,enzyme activity and microbial quantity of rhizosphere soil of stevia continuous cropping were studied by applying different fertilization treatments in three consecutive cropping years of stevia continuous cropping.In order to provide a reliable method to solve the problem of continuous cropping obstacles in the actual planting and production of stevia stevia and improve the yield and quality of stevia stevia.The main findings are as follows:1)compared with the control group,the plant height and stem diameter of continuous cropping stevia were increased with different fertilization treatments,among which amino acid fertilizer + bacterial fertilizer treatment had the greatest promoting effect on plant height and stem diameter in 5 and 10 years of continuous cropping compared with other treatments.In field experiments,the plant height and leaf length of stevia stevia were significantly increased by high potassium compound fertilizer treatment compared with other fertilization treatments.2)fresh weight,dry weight and root length of stevia were increased in 3 consecutive cropping years with different fertilization treatments.In the three consecutive cropping years,the fresh and dry weight of stevia stevia were significantly increased by the combination of bacterial fertilizer with organic fertilizer or compound fertilizer.Compared with other treatments in 5-and10-year continuous cropping soil,bacterial fertilizer treatment can promote root elongation.In the 15-year continuous cropping soil,high potassium compound fertilizer treatment had the greatest effect on root growth.3)the N,P and K contents of stevia stevia treated with bacterial fertilizer and high potassium compound fertilizer were the highest in the5-year continuous cropping soil.The N and K contents of stevia stevia were the highest in10 years of continuous cropping.Among the 10-and 15-year continuous cropping soils,treatment with high potassium compound fertilizer and bacterial fertilizer had the greatest effect on the reduction of MDA content.Different fertilization treatments significantly increased SOD activity in the three consecutive cropping years.In the five and ten consecutive cropping years,amino acid fertilizer treated stevia stevia showed the highest SOD activity,while in the 15 consecutive cropping years,amino acid fertilizer + bacterialfertilizer treated stevia stevia showed the highest SOD activity.4)the contents of RA and RC were significantly increased in the three consecutive cropping years by the treatment of high-potassium compound fertilizer + bacterial fertilizer,and the increase of RA and RC was the largest in stevia stevia in the five consecutive cropping years.5)in the three consecutive cropping years,the soil sucrase and urease activities of each fertilization treatment were higher than the control without fertilization in different periods,but the growth rates of enzyme activities in different periods were different.Compared with the control without fertilization,the number of soil fungi was decreased and the number of bacteria was increased.The activity of sucrase and urease increased the fastest in the soil treated with compound fertilizer + bacterial fertilizer,and the bacteria increased the fastest in the soil treated with high-potassium compound fertilizer + bacterial fertilizer.In 10 years of continuous cropping soil,bacteria treated with high potassium compound fertilizer and amino acid fertilizer increased the fastest.In the 15 years of continuous cropping soil,the bacteria treated with high potassium compound fertilizer increased the fastest.The results showed that single application of high potassium compound fertilizer or combined application of organic fertilizer had a great influence on the microbial quantity of continuous cropping soil.