Distribution Characteristics Of Soil Sulfur And Its Influencing Factors In Spartina Alterniflora Wetland In Jiaozhou Bay

Jiaozhou Bay Wetland,located in Qingdao,is the largest coastal wetland in Shandong Peninsula,and is also a treasure trove of Qingdao's natural resources.Wetland,as a complex ecosystem,has an important impact on ecology and environment.The sulfur element,as the fourth important nutrient elements behind nitrogen,phosphorus and potassium,has an important role in the process of plant growth and development.At the same time,it has an important significance to maintain the healthy development of the ecosystem.The biogeochemistry process of sulfur plays an important role in the wetland ecosystem,in order to better understand the position and role of sulfur in the wetland ecosystem.The research regards Jiaozhou Bay Spartina alterniflora Wetland as the main research area.Through field sampling and laboratory experiments,we can get the available sulfur content by using the method of calcium chloride extracted-Barium sulfate turbidimetry,and we can know the total sulfur contents by using the method of acid digested-barium sulfate turbidimetric,in order to explore the temporal and spatial distribution characteristics of the soil sulfur concents in S.alterniflora wetland.In addition,the influence factors related to the soil sulfur content in S.alterniflora wetland were detemined by using the methods that were often used to determine the physical and chemical properties;meanwhile the differences of the soil sulfur content and the corresponding temporal and spatial distribution characteristics in grassland and mudflat were contrasted and analysed;revealing the influence of exotic S.alterniflora on the soil sulfur in Jiaozhou Bay Wetland,and the correlation between soil physical and chemical properties and the contents of soil sulfur in wetland,in order to provide basic data for to understand the characteristics of nutrient elements in Jiaozhou Bay S.alterniflora Wetland.The main results of this study are as follows:(1)The vertical distribution characteristics of soil total sulfur and soil available sulfur in 0-60 cm soil layer of Jiaozhou Bay S.alterniflora wetland in 2015 and 2016 on the whole were the content gradually decreased from top to bottom.(2)Compared respectively the contents of soil total sulfur and available sulfur of S.alterniflora zone and mudflat in 2015 and 2016,we can know that the contents in S.alterniflora zone were higher than those in mudflat.(3)The soil total sulfur average contents in 0-60 cm soil layer of S.alterniflora wetland in 2015 and 2016 were 1.49 g/kg,1.34 g/kg respectively and the soil available sulfur average content were 651.56 mg/kg,696.54 mg/kg respectively.So the total sulfur content in soil is decreased while soil available sulfur content is rising in 2016.(4)The content of soil total sulfur of Jiaozhou Bay S.alterniflora Wetland in 2015 year changes with the seasons,and decreased first and then increased and then decreased and with seasonal variation the soil available sulfur content increased first and then decreased;While the contents of soil total sulfur and soil available sulfur were all decreased gradually with the season changing.The content of soil total sulfur of Jiaozhou Bay S.alterniflora Wetland in 2016 changes with the time,the lowest in June,the highest in September;soil available sulfur content was the lowest in June.The content otherness among September,October,November was small.While highest content of the soil total sulfur was in June and lowest in October;the soil available sulfur content was gradually reduced with the monthly variation and the highest content in June and the lowest in November.(5)Each organ of S.alterniflora has different accumulation ability on the same element,the contents of total sulfur in them are different.The total sulfur content in different organs of S.alterniflora in 2015 was root > leaf > stem.The total sulfur content in different organs of S.alterniflora in 2016 roughly as follows: leaf > root > stem.(6)The main factors affecting the soil sulfur content variation of Jiaozhou Bay S.alterniflora Wetland are soil organic matter,soil soluble salt content and pH.The content of soil organic matter and soluble salt were significantly positively correlated with the content of sulfur in soil(P<0.01),and soil pH was significantly negatively correlated(P<0.01).