Correlation Between Soil Physicochemical Properties And Soil Nematodes And Microorganisms Under Different Vegetation Conditions In Jiangsu Coastal Areas

Coastal tidal flat is one of the most important soil resources in the coastal area.Due to the degradation of the coastline,the area of tidal flat is increasing.The soil in these areas cannot be directly used by human because of high soil salinity and poor soil fertility.In some areas,after decades of natural succession,natural plants have grown;and some areas have been artificially modified to grow crops for human use.The study of changes in soil during natural succession and human improvement has a crucial role in the rational development and utilization of human for using coastal tidal flat.The Yellow Sea Seashore(N33°16.87',E120°46.56'),the saline soil land park(N33°16.48',E120°43.55')and the Dafeng(N33°13.93',E120°40.27'),Xinyang(N33°32.16',E120°26.42')and Shuntai(N33°41.82',E120°23.41')Jerusalem artichoke plantations in Jiangsu Province were selected as research areas in this study.There were few human disturbance factors in the seaside of the Yellow Sea,a certain amount of human disturbance in the saline soil park,and relatively large human disturbance in the Jerusalem artichoke planting area.Through research on the physicochemical properties,enzyme activities,soil mineral composition,soil nematodes,microbes and root exudates of different niche soils,deepen the study of coastal tidal flat,and provide reference for ecological protection and rational development and utilization of coastal tidal flat.The main findings are as follows:1.Soil pH and salinity of Dafeng and Xinyang Jerusalem plantations were significantly lower than those of other natural plots,while organic matter,total nitrogen,total phosphorus and available phosphorus The content is significantly improved compared to other natural plots,indicating that artificial improvement(such as planting Jerusalem artichoke)has significantly improved soil fertility levels and soil quality of coastal tidal flat.2.Soil enzyme activities of Dafeng and Xinyang Jerusalem plantations were higher,and the enzyme activities of vegetation soils were higher than the control soil,indicating that artificial improvement(such as planting Jerusalem artichoke)has a significant increase in soil enzyme activity,and plant growth and development also promotes soil enzyme activity.3.Quartz,albite and calcite are the three main minerals in all soil samples.The total content of quartz and albite is higher than 50%,which is an absolute dominant position and belongs to the typical silty clay loam.4.There were 4 kinds,23 species of nematodes in the soil samples.Generally speaking,the soil fertility and soil quality along the beach were poor compared with other terrestrial ecosystems.In terms of quantity,the soil nematode biomass of Jerusalem artichoke planting area was significantly higher than other plots,indicating that the soil quality of Jerusalem artichoke planting land was better than other natural plots.5.Illumina high-throughput sequencing showed that 46 phylum and 683 genera were found in all soil samples in this experiment.Proteobacteria,Bacteroidetes,Actinobacteria,Chloroflexi,Acidobacteria and Gemmatimonadetes were the dominant species in all samples,while the relative abundance varies greatly in each soil sample.6.The root exudates detected in this study are mainly divided into the following 8 categories:acid anhydrides,aromatic hydrocarbons,alkanes,ketones,phenols,amines,alcohols and acid lipids.Acid lipids,alcohols,amines and phenols are found in all rhizosphere soil samples with the highest levels of acid lipids.The experimental results show that the physicochemical properties,enzyme activities,soil mineral composition,soil nematodes,soil microbes and root exudates of different ecological niches in the coastal areas are different.The indexes of Jerusalem artichoke planting sites are much different from other natural plots,indicating that artificial improvements(such as planting Jerusalem artichoke)have significant changes in soil fertility levels and soil quality.In addition,by analyzing the correlation between soil physicochemical properties,enzyme activity,soil mineral composition,microbial and root exudates,most of the indicators have a certain correlation.For example,there is a significant negative correlation between soil pH and salinity and organic matter,NH4+-N,total N,total P and available P.There is a significant positive correlation between alkaline phosphatase and invertase and organic matter,total N,total P and available P,and a significant negative correlation with soil pH and salinity.There is also a significant positive correlation between microbial community diversity and organic matter,total N,total P,available P and alkaline phosphatase,and a significant negative correlation with soil pH and salinity.Acid lipids and alcohol compounds in root exudates promote microbial community diversity,while amine compounds have inhibitory effects,andthese indicators interact and are interrelated.All the research in this experiment aims to deepen the research on the soil along the beach and provide constructive advice for the ecological protection and rational development and utilization ofcoastal tidal flat.