We explored the effects of different fertilization treatments on soil structure,nutrient characteristics,bio-logical characteristics and yield of continuous cropping sugar beet,with the aim to screen out the best application amount of bioorganic fertilizer.With the conventional fertilization(900 kg·hm-2 chemical fertilizer)as the control(CK),we set up bioorganic fertilizer treatments(BOF1:1500 kg·hm-2;BOF2:3000 kg·hm-2;BOF3:4500 kg·hm-2;BOF4:6000 kg·hm-2;BOF5:7500 kg·hm-2)on the basis of reducing 300 kg·hm-2 chemical fer-tilizer.The results showed that the effects of BOF1 on soil quality indices were not significant.The BOF2 signifi-cantly increased the content of soil organic matter and available potassium.The BOF3 significantly reduced soil bulk density by 5.11%,significantly increased soil total porosity by 5.92%,soil organic matter by 14.07%,soil alkaline nitrogen by 18.35%,soil available phosphorus by 3.59%,and soil available potassium by 14.61%.Treatments BOF4 and BOF5 had similar effects on soil quality and beet yield.BOF4 and BOF5 significantly reduced soil bulk density by 9.33%and 9.65%,significantly increased soil porosity by 10.82%and 11.19%,soil organic matter by 27.22%and 27.78%,soil alkaline nitrogen by 31.62%and 35.42%,soil available phosphorus by 44.10%and 54.87%,soil available potassium by 22.93%and 30.03%,respectively.Both treatments significantly increased soil microbial biomass carbon by 22.78%-44.19%and 23.81%-60.17%,microbial biomass nitrogen by 2.45%-37.64%and 16.74%-43.56%,invertase activity by 26.03%-38.61%and 29.27%-44.71%,urease activity by 42.72%-63.20%and 51.59%-69.89%,alkaline phosphatase activity by 3.59%-33.44%and 29.60%-38.62%.There were no significant differences in each soil quality index between these two treatments.Compared with CK,the yield of BOF2,BOF3,BOF4 and BOF5 increased by 5.69%,11.82%,22.29%,and 11.95%,respectively.The beet yield of treatment BOF4 was significantly higher than that of BOF2,BOF3,and BOF5.Treatment BOF4 increased the economic benefits of continuous cropping sugar beet by 12.79%.In all,the application of 6000 kg· hm-2 bioorganic fertilizer can achieve the synergetic improvement of soil quality,yield and economic benefits of continuous cropping sugar beet.
reduction of chemical fertilizerbioorganic fertilizercontinuous cropping sugar beetsoil qualityyieldeconomic benefit