| Sporobolus alterniflorus was introduced into China in the last century.It can grow intensively,with strong resistance and fertility,leading to ecological imbalances in the tidal flats and siltation of the channel.At the same time,it poses a serious threat to native plant species and birds and needs to be treated.Mangroves grow in the intertidal zone of tropical and subtropical coasts,which are woody plants with significant social,economic and ecological benefits.Kandelia obovata has been the important species in China's coastal wetland mangrove ecosystem restoration project.In this study,we have developed a bio-physical prevention and control method based on the principles of bio-substitution and competitive exclusion principle,which is made of “castration + clipping + cover film + planting mangrove plant + recycling film” to control S.alterniflorus.This method has achieved good results.This study is based on the study of Ecological effect study of control S.alterniflorus by K.obovata.We establish the "Quanzhou Bay coastal wetlands S.alterniflorus prevention and ecological restoration demonstration base" for our plots.In this study,we investigated and analyzed the population characteristics and physiological and ecological effect of control S.alterniflorus by K.obovata of mangrove in Quanzhou Bay.The research results are as follows:(1)The clipping can significantly reduce the plant height,plexus diameter,fresh weight and dry weight of S.alterniflorus,but after a whole year,the density of S.alterniflorus increases.The contents of carbon,nitrogen and phosphorus in the leaves of clipped S.alterniflorus and their C/N,C/P were significantly different from those of untreated plants,but N/P was similar.It shows that clipping can inhibit the growth of S.alterniflorus to a certain degree,but the effect caused by clipping is basically not obvious after a whole year recovery.(2)Using bio-physical patented method to control S.alterniflorus,with the growth of K.obovata,the advantages of low-density planting mode are gradually reflected.Especially to the end of second growth year.The plant height,crown width,root length,biomass,absolute growth rate and leaf organic carbon content of K.obovata with 100×100 cm planting spacing were significantly higher than others.Its carbon sequestration level and P utilization efficiency are the highest among the four planting modes.The total nitrogen content of K.obovata at different planting modes did not differ significantly,and the growth of K.obovata in different planting densities in Quanzhou Bay may be limited by nitrogen.(3)It can be seen that the intensive planting mode(25×25 cm?50×50 cm)will cause the chlorophyll content of K.obovata to decrease,but has little effect to the ratio of chlorophyll a and b.As the planting density increased,the activity of the antioxidant enzyme system also increased,but even the 25×25 cm planting mode did not show a decrease,indicating that the intensive planting mode did not cause irreversible damage and is still within its tolerance threshold.The results show that the 100×100 cm planting mode is the most suitable for the growth of the twoyear-old K.obovata,with the least stress.(4)After the second year of planting K.obovata,the 100×100 cm planting mode can effectively increase the soil organic matter content of the upper and lower layers,increase the total N and P content of the soil,and reduce the salinity and pH of the soil leachate to improve the soil properties.Combine the above conclusions,we believe the bio-physical patented method has a significant effect on controlling the invasion of S.alterniflorus.Studies have shown that the growth status,nutrient content,stress resistance and soil physical and chemical properties of K.obovata in the 100×100 cm planting mode were better than the others at the end of the second year.It is suggested that this method and planting mode can be adopted in the ecological restoration of coastal wetlands. |
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