Study On Soil Microbial Diversity And Soil Enzyme Activity In Yellow River Delta Wetland

Soil microbial and soil enzymes play an important role in improving soil environment and the researches on them have been paid more and more attention by scholars at home and abroad.Soil microbial have many functions,for example,promoting decomposition of organic matter to release nutrient element,improving soil structure and promoting decomposition of minerals in soil.Soil enzymes are beneficial to the decomposition and synthesis of organic matter in soil.The study of soil enzyme activity is beneficial to grasp the decomposition and synthesis efficiency of organic matter in soil.Therefore,the study of soil microbial with soil enzyme activity can facilitate people to understand the changes of soil microenvironment and soil fertility in time.This study was based on soil microbial diversity with soil enzyme activity about different vegetations,different repair times and different hydrological conditions in the Yellow River Delta Wetland.The main findings are as follows.1.The seasonal change of soil microbial nunber in different vegetation typess was as follows,autumn>spring,bacteria>actinomycetes>fungi.The number of bacteria increased from 10~5in spring to 10~7in autumn,The number of fungi increased from 10~4in spring to 10~5in autumn,The number of actinomycetes increased from 10~5 in spring to 10~6 in autumn,the results showed that the seasonal variation will affect soil microbial number.The number of bacteria in spring was as follows,reed-suaeda salsa>reed>suaeda salsa,bout in autumn,reed>reed-suaeda salsa>suaeda salsa.The number of fungi in different season was as follows,reed-suaeda salsa>suaeda salsa>reed.The number of actinomycetes in spring showed that reed>reed-suaeda salsa>suaeda salsa,but in autumnshowed that reed>reed-suaeda salsa>suaeda salsa.In the same season,the number of soil microbial in different vegetation types was different,which indicates that vegetation types will affect the number of soil microbial.2.The seasonal change of soil microbial number in different repair time region was as follows,autumn>spring,bacteria>actinomycetes>fungi.In spring,the number of bacteria showed that 2001>2009>2015,the number of fungi showed that 2001>2009>2015,the number of actinomycetes showed that 2009>2001>2015.In autumn,the number of bacteria showed that 2009>2015>2001,the number of fungi showed that 2001>2009>2015,the number of actinomycetes showed that 2009>2015>2001.In general,the total number of soil microbial showed that 2009>2001>2015.The results showed that the number of soil microbes increased first and then decreased with the increase of repair time.3.The influence of hydrological conditions on soil microbial number was as follows,the number of soil microbial in non-flooded area was higher than that in flooded area.The number of bacteria,fungi and actinomycetes in non-flooded area was 22.5 times,53.5 times and 16.3times than in flooded area.The number of soil microbes in both regions was as follows,bacteria>actinomycetes>fungi.This shows that hydrological conditions have an impact on soil microbial number,excess water will reduce soil microbial number.4.The effect of seasonal changes on soil enzyme activity in different vegetation types was as follows,the activity of urease,sucrase,phosphatase and polyphenol oxidase in three vegetationg types was higher in autumn than in spring.The activity of amylase,catalase,peroxidasein autumn were less than in spring,the activity of ascorbate oxidase in reed and Suaeda salsa vegetationg was higher in autumn than in spring,but autumn was less than spring in reed-Suaeda salsa mixed vegetation.In the same vegetation,soil enzyme activity varies with the seasons.Soil enzyme activity was different in different vegetation types in the same season.In general,soil enzyme activity was affected by the seasons and vegetation types.5.The effect of seasonal changes on soil enzyme activity in different repair time regions was as follows,the activitiy of soil urease,sucrase,phosphatase,catalase and polyphenol oxidase in autumn were higher than in spring.The activity of amylase,peroxidase and ascorbic acid oxidase were lower in autumn than in spring.The activity of urease,phosphatase,catalase peroxidase,polyphenol oxidase increased with the increase of repair time,and the five enzymes could be used as the index of repair time.6.The activity of phosphatase and catalase in flooded area was higher than in non-flooded areas,the activity of urease,sucrase,amylase,peroxidase,polyphenol oxidase and ascorbic acid oxidase were lower than in non-flooded area.This indicated that water stress could increase phosphatase and catalase activity,Hydrological conditions could affect soil enzyme activity.7.Correlation analysis of soil microbial number,soil enzyme activity,physical and chemical properties of soil showed that,the number of bacteria was positively correlated with urease and ascorbic acid oxidase activity,but positively correlated with sucrase,amylase and polyphenol oxidase activity.The number of fungi was positively correlated with urease and phosphatase activity and polyphenol oxidase activity.There was a significant positive correlation between the number of actinomycetes and the activities of sucrase and peroxidase.This shows that soil microbial and soil enzyme were closely related.The activity of urease was positively correlated with organic matter,total nitrogen and total phosphorus,and negatively correlated with pH.The activity of amylase was negatively correlated with pH,the activity of phosphatase was positively correlated with organic matter and positively correlated with total nitrogen.Polyphenol oxidase activity was positively correlated with total phosphorus.The results showed that there was a negative correlation between pH and soil enzyme activity,so pH could inhibited soil enzyme production,We should consider the effect of pH that in the process of soil remediation by soil enzymes.Urease activity was positively correlated with polyphenol oxidase activity.There was a significant positive correlation between sucrase activity and phosphatase activity and a very significant positive correlation between sucrase activity and ascorbic acid oxidase activity.Amylase activity was positively correlated with phosphatase activity.Catalase activity was negatively correlated with polyphenol oxidase activity.Peroxidase activity was positively correlated with polyphenol oxidase activity and negatively correlated with ascorbic acid oxidase activity.