Effects Of Planting Years On Rhizosphere Microecological Environment Of Cherry

Cherry is rich in nutrients and sweet and sour.It was used for economic cultivation in the 16th century.Now it has developed into a worldwide fruit tree.Cherry has a good health function and has achieved considerable economic benefits in recent years.At present,cherries are widely planted in Shandong Province,but with the increase of planting years,the soil environment deteriorates gradually and pests and diseases occur frequently,which not only affects the yield and quality of cherries,but also deteriorates the quality of land,which limits the better development of cherry industry.There are few reports about the effects of cherry planting years on soil micro-ecological environment at home and abroad.In order to investigate the effects of planting years on the microecological environment of cherry rhizosphere soil,the physical and chemical properties,enzyme activities,phenolic acids and microbial changes of cherry rhizosphere soil in Yantai City,Shandong Province for 5,10,15,20 and 25 years,and Ping’an County,Qinghai Province for 5,10 and 15 years were studied in this paper.The effects of vegetable and abiotic factors were aimed at finding out the indicators reflecting soil deterioration,in order to provide theoretical and practical basis for regulating cherry planting management and the accumulation of soil health.In addition,growth-promoting bacteria with good application potential were screened from cherry rhizosphere soil in order to lay a foundation for the production of bio-fertilizer.The main contents and conclusions of this study are as follows:1.The changes of physical and chemical properties of cherry rhizosphere soil are different in different planting years.With the increase of planting years,soil PH in Yantai,Shandong Province and Ping’an,Qinghai Province did not change significantly.Soil alkali-hydrolyzed nitrogen,available phosphorus,available potassium and organic matter content continued to increase,among which alkali-hydrolyzed nitrogen and available potassium content increased rapidly.2.The changes of soil enzyme activity in Cherry rhizosphere were different in different planting years.With the increase of planting years,soil urease activity in Yantai,Shandong Province showed an irregular change trend,among which soil urease activity in25 years was the highest(2.78mgNH₄-N·g^-1 24h^-1),which was significantly different from that in other years.Soil urease activity in Ping’an,Qinghai Province was higher than that in Yantai,Shandong Province,and its activity increased first and then decreased with the increase of planting years.Soil phosphatase activity and invertase activity decreased with the increase of planting years,that is,the longer the planting years,the lower the enzyme activity.Soil catalase activity increased with the increase of planting years in Yantai,Shandong Province,with the highest activity in 25 years(0.11mol·L^-1 KMnO₄ ml·g^-1),while catalase activity decreased with the increase of planting years in Ping’an alkaline soil in Qinghai Province.But its activity is higher than that of Yantai,Shandong Province.3、The changes of phenolic acids in Cherry rhizosphere soil were different in different planting years.The contents of benzoic acid,vanillin and cinnamic acid in Cherry rhizosphere soil were significantly increased with the increase of cherry planting years in both acidic and alkaline soils,and the contents of phenolic acids in Cherry rhizosphere soil after 25 and 15 years of continuous cropping were significantly higher than those in non-continuous cropping soils,which were 0.064μg·Kg^-1and0.031μg·Kg^-1,0.050μg·Kg^-1and 0.025μg·Kg^-1,respectively.0.031μg·Kg^-1 and 0.012μg·Kg^-1cinnamic acid.4、The changes of microbial biomass in rhizosphere soil of different cherry rootstocks and planting years were different.With the increase of cherry planting years,the number of harmful fungi in soil increased,while the number of beneficial fungi and bacteria decreased.The results showed that the increase of planting years would change the proportion of soil microorganisms,increase harmful microorganisms,and affect the growth and development of plants.Different cherry rootstocks had different aggregation effects on microorganisms,such as in Mahali’s rhizosphere soil.There were more beneficial microorganisms and more harmful microorganisms in Gisela 6.5、Screening and identification of cherry rhizosphere growth-promoting bacteria.Three bacteria with good application potential were screened from cherry rhizosphere soil.Their sequencing results were compared with Blast in Gen Bank nucleic acid database on NCBI website.The results showed that the three bacteria were Exiguobacterium,Bacillus cereus and Bacillus methylotrophicus.