Effects Of The Invasion By Trifolium Repens L.on Soil Animal In Urban Turfgrass Ecosystem

Invasive plants cause huge losses to agroforestry in China,which can affect the entire invasive soil ecosystem.Soil animal is an important part of soil ecosystem,which affects the energy flow and material circulation of the soil ecosystem,and its survival condition can reflect the quality of soil.After the invasion of alien plants,soil animals were directly or indirectly affected,which changed the whole soil ecosystem.At present,most of the research objects of alien plant invasion are concentrated in farmland,lakes,wetlands,desert and other ecosystems,and few research on the urban lawn ecosystem,and turf is a very important form of urban landscape greening.The invasion of foreign plants to the urban lawn landscape has caused serious damage and greatly increased the maintenance cost.The Trifolium repens L.is one of them.The study of the effect of the invasion of T.repens L.on the soil animal in the urban lawn ecosystem can provide a theoretical basis for understanding the invasion mechanism of exotic plants and taking measures to build and maintain the urban lawn ecosystem.In this paper,the soil animal community and soil physical and chemical properties of 4 invasive T.repens L.samples with different invasive degree were studied by field observation,and the laboratory control experiment was used to carry out acute and chronic toxicity experiments on earthworms,and the effects of allelochemicals on Soil animals were studied.The results show that:1,A total of 30099 individuals of soil animal,which belong to 19 orders,43 families were collected..Among them,the most dominant groups were Poduridae,Laelapidae,Rhabditidae and Enchytraeidae.The individuals and the number of soil animal groups were significantly different among the sampling areas.2,The order of group number and individuals was moderate invasion > mild invasion > control > severe invasion.This phenomenon is consistent with the intermediate disturbance hypothesis.The analysis of variance showed that the number of soil animals in the T.repens L.was significantly different(F=10.469,P<0.01),and there were significant differences between different seasons(F=3.424,P<0.05)in different seasons(F=3.424,P<0.05),and the individual number of soil animals was very significant(F=9.541,P<0.01)and soil animals under different invasive degrees of T.repens L..There was a significant difference in the number of individuals in the season(F=6.585,P<0.01).The seasonal dynamics of individual number and group number of soil animals were mainly in summer and autumn,and low in spring and winter.3,The proportion of individual number and group number of soil animal functional groups is rotten food > herbivorous > predatory > omnivorous.The predatory soil animals changed with the seasons,the highest in autumn and winter,the lowest in spring and summer,and the opposite of the phytophagous soil animals.The trend of the predatory soil animals with the invasion degree was the severe invasion > the control > mild invasion > moderate invasion,and the change trend of the phytophagous soil animals was opposite.4,The soil pH under different invasions of T.repens L.was between 6.84-7.12 and neutral.The analysis of variance analysis showed that there was no significant difference in soil pH value and available P under different invasions;soil water content,ammonium nitrogen and quick acting K under different invasions were significantly different.The invasion of T.repens L.significantly affected the contents of ammonium and available potassium in soil.Pearson correlation analysis showed that ammonium nitrogen was the most influential soil physicochemical factor for soil animals.CCA sequencing showed that soil physical and chemical factors had little influence on dominant groups,which mainly affected the common groups and rare groups.5,The effect of the T.repens L.water extract on the acute lethal effect of earthworms was not significant.At the maximum concentration,it did not reach the semi lethal concentration of the acute toxicology experiment.The variance points showed that the effect of different concentration of T.repens L.water on the small and medium dry soil animals was not significantly different.The toxicity of different concentration of water extract to Eisenia Eisenia was different in chronic exposure experiment.The toxicity of T.repens L.aqueous extract increased with the increase of concentration.In 60 days,the earthworms' weight change rate,cellulase activity,glutathione transferase(GST)activity and superoxide dismutase(SOD)activity of earthworms were significantly different from those of the control(P<0.05).It was shown that the growth and development of earthworms were influenced by the invasion of the three leaves.The study showed that a certain degree of T.repens L.invasion increased the diversity of soil animal community,but when it reached severe invasion,the T.repens L.formed a single community and reduced the plant diversity.In addition,soil animals can get less resources and reduce diversity of soil animal communities.The invasion of T.repens L.may be mainly to change the content of soil physical and chemical factors through allelopathy,which affects common groups and rare groups of soil animals,and ultimately affects the characteristics of soil animal communities.In the management of urban lawn,the T.repens L.,which has been invaded,should be cleaned in time to prevent a large number of breeding,reduce the diversity of species,affect the normal growth of soil animals,and be not conducive to the maintenance of soil fertility.