| This research took the large-scale nursery of Tongzhou in Beijing as a study location.Following the soil fertility evaluation,we therefore tried to assess the improved mechanisms of green waste compost impacts on nursery soil fertility via organic carbon fractions,enzyme activity,bacterial and fungal community structures.Furthermore,we also focused on the effects of green waste compost on nursery stocks growth and tried to select the optimal fertilization treatment.More importantly,our research highlights the supplement about green waste recycling,but also provided the scientific basis for nursery fertilization management and soil quality improvement.The main results were as below.（1）By the investigation of soil fertility,we found that the content of soil organic matter（OM）,total nitrogen（TN）,available nitrogen（AN）,available phosphorus（AP）,and available potassium（AK）were 1.03-31.30 g?kg-1,0.13-1.25 g?kg-1,4.90-84.00 mg?kg-1,9.25-146.11 mg?kg-1 and 35.06-209.34 mg?kg-1,respectively.Thus,the evaluation of soil nutrients was in the middle and lower level,and the soil fertility was weak.（2）Our pot experiment research compared with chemical fertilizer（MF）after 1-year fertilization,which indicated that:（1）The content of soil OM,TN,ammonium nitrogen（NH4+-N）,AP,AK,available iron（Fe）,available manganese（Mn）,and available（Zn）were significantly increased by 32.73-131.33%and 13.54-166.00%under compost（GF）and 50%chemical fertilizer+50%compost（MGF）treatments,these results showed that compost could significantly improve nursery soil fertility.（2）The content of soil fulvic acid carbon（FAC）,humic acid carbon（HAC）,dissolved organic carbon（DOC）,and glomalin-related soil protein carbon（GRSPC）were significantly increased by 30.14-177.06%and 30.14-100.00%under GF and MGF treatments.The sensitivity coefficient of GRSPC was 229.03%under GF treatment,and positively correlated with soil nitrogen and phosphorus content,which indicated that GRSPC was an important soil fertility indicator.MGF treatment significantly increased soil aromatic compounds peak area up to 400.47,which complicated the organic carbon structure and enhanced stability for soil carbon fixation.（3）The activities of soil sucrase,urease,protease,alkaline phosphatase,dehydrogenase,and catalase were significantly increased by 24.14-425.15%and 2.34-539.31%under GF and MGF treatments.Soil catalase activity had a better explanation for nutrients and organic carbon fractions and account for 74.10%and 54.30%.These results showed that compost could promote organic carbon decomposition and release nutrients by increasing soil catalase activity.（4）The content of soil nutrients and organic carbon fractions was explained for 90.76%and 72.46%about bacterial community structure changes,respectively,and soil AP and GRSPC content were the key factors affecting bacterial community structures.（5）The content of soil nutrients and organic carbon fractions explained 87.37%and 60.56%of fungi community structure changes,and soil OM and DOC content were the key factors affecting fungi community structures.（3）The Field experiment compared to MF treatment indicated,the biomass of Malus×micromalus Makino leaves,branches,and trunks were significantly increased by 13.85%,11.11%,and 10.10%under MGF treatment.and nitrogen accumulation,soluble sugar,and soluble protein content in leaves were significantly increased by 17.34%,6.21%,and 22.24%.The comprehensive evaluation of nursery stock growth indicators showed that the MGF treatment index was 0.95 and ranked first.In conclusion,green waste compost could improve nursery soil fertility by affecting GRSPC,catalase activity,and microbial community structures.The secretion of GRSPC increased with highly and sensitivity coefficient,this result suggested that it was significantly positively correlated with soil nitrogen and phosphorus content,catalase activity,and bacterial community structures,which concluded that GRSPC was an important soil fertility indicator.The activity of catalase accelerated the redox reaction rate,decomposed soil organic carbon,and release nutrients.This increment of soil AP and OM content also determined soil microbial community structure changes.MGF treatment had the best nursery stock growth effect and was the best-recommended solution for the nursery fertilization management process.Taken together,our studies have important value and practical meaning for improving the forest land soil quality and scientifically cultivating nursery stocks. |
