| Picea koraiensis is an important afforestation tree species in north China,and its initial growth is slow.Fertilization is an important forest management measure to promote the growth of stands,which has a significant impact on soil fertility and soil microorganisms.Therefore,in this paper,by applying(N,NP and NPK)fertilizers to the 10 a juvenile Picea koraiensis,studying the response of stands growth,leaf anatomy,mycorrhizal colonization rate,soil nutrients,and soil microorganisms to fertilization.It is of great significance for establishing fertilization and tending measures for juvenile Picea koraiensis plantations.The findings are as follows:(1)During the growing season,fertilization increased the height annual growth and ground diameter annual growth of juvenile Picea koraiensis,increased the area of mesophyll tissue,transfer tissue,resin lumen and phloem of leaves,reduced mycorrhizal colonization rate and soil pH,and increased the effective phosphorus content of different soil layers.Among all the fertilization measures,the effect of NPK fertilizer was the best.After one growing season of N,P and K compound fertilizer,the ground diameter and height of juvenile Picea koraiensis were 47.04%and 14.55%higher than those of the non-fertilized control.(2)Compared with the application of NPK fertilizer in the growing season,the application in fall enhanced the height annual growth,ground diameter annual growth and crown diameter annual growth of juvenile Picea koraiensis,increased the area of leaf endodermis,mesophyll tissue,transfer tissue,vascular bundle,xylem,phloem and resin channel,but had no significant effect on the mycorrhizal colonization rate and soil nutrient content.After fertilization in autumn,the juvenile stands'ground diameter and tree height were 37.66%and 70%higher than those of the non-fertilized control,respectively,and 13.98%and 36%higher than those in the growing season.(3)Compared with the single liberation cutting,the coupling treatment of fertilization in growth season and liberation cutting improved the ground diameter annual growth of young Picea koraiensis,promoted the change of leaf anatomical structure,reduced the soil pH and mycorrhizal colonization rate,and increased the content of total carbon,total nitrogen,organic matter,total phosphorus,available phosphorus and available potassium in 0-20cm soil layer.After the growing season fertilization and crown thinning coupling treatment,the young stands'ground diameter and stands height were 10%and 23.88%higher than those of the non-fertilized control,respectively,and 13.49%and 13.49%higher than the single NPK fertilizer treatment.5.12%.(4)Fertilization in growing season changed the composition of fungi community in rhizosphere and non-rhizosphere soil.Ascomycetes and basidiomycetes were the dominant communities of rhizosphere and non-rhizosphere soil fungi under fertilization.In rhizosphere soil,all kinds of fertilization treatments resulted in the decrease of ascomycete abundance and the increase of basidiomycete abundance.However,in non-rhizosphere soil the effects of different fertilization treatments were different:N and NP fertilization reduced Ascomycete abundance,but increased Basidiomycete abundance,while NPK fertilization had the opposite effect.The results of a diversity analysis showed that the fungal richness index of rhizosphere soil was higher than that of non-rhizosphere soil,but the diversity index was lower than that of non-rhizosphere soil.Among all kinds of fertilization treatments,N fertilizer had the highest fungal richness index in rhizosphere soil,while NP fertilizer had the highest fungal diversity index in rhizosphere soil.NPK application increased the fungal richness index and decreased the diversity index of non-rhizosphere soil.In conclusion,it was found that fertilization increased the growth of juvenile Picea koraiensis,and the effect of liberation cutting combined with fertilization is the best.Fertilization can increase soil nutrient content,soil fungal richness index and diversity index,and reduced soil pH and mycorrhizal colonization rate.In order to adapt to the condition of fertilization,the area of leaf tissue was increased and the efficiency of nutrient transportation was improved.The results of this study provide a reference for the establishment of fertilization and tending measures to effectively promote the growth of juvenile stands of Picea koraiensis. |
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