Four kinds of plant materials (astragalus, azolla, rice straw and water hyacinth) were allowed to decompose for 10 years in two soils with different mineralogical characteristics in fields under upland and submerged c...Four kinds of plant materials (astragalus, azolla, rice straw and water hyacinth) were allowed to decompose for 10 years in two soils with different mineralogical characteristics in fields under upland and submerged conditions. Greater amounts of C and N from azolla were retained in soils throughout the 10-year experimental period compared to those from the other plant materials. The residual C Of all the plant materials in the two soils under upland conditions mineralized st rates corresponding to half-lives between 4.4-6.6 years,while the corresponding figures for thine under submerged conditions were between 6.5-13.1 years. Minerallization of residual organic N followed the same pattern as residual C. Compared to residual C, however, the mineralization rates of residual organic N in most cases were significantly lower and the percentages of added N regained in sons were higher. More N from plat materials was retained in the yellow-brown soil than in the red soil, but no consistent differences in the amounts of C from plant materials and in the mineralization rates of both residual C and residual organic N between the two soils could be found.展开更多
Urban afforestation is an important strategy for promoting sustainable urban development.In cities where large new green spaces are not available,the planting of curbside trees is deemed to be an important afforestati...Urban afforestation is an important strategy for promoting sustainable urban development.In cities where large new green spaces are not available,the planting of curbside trees is deemed to be an important afforestation strategy.However,variations in the ecosystem services provided by street tree assemblages across socioeconomic gradients have been unexplored.We examined such variations in ecosystem services provided by street tree assemblages along an urban–suburban continuum.Our findings were as follows.(i)Not all ecosystem services showed increasing trends along the urban–suburban continuum.Some ecosystem services at the street tree assemblage level,such as air purification and rainfall interception were prominent in areas of high urbanization intensity.(ii)Diverse ecosystem service trends were found in relation to differential characteristics of street trees assemblages.Structural properties of street tree assemblages,such as tree density and age structure,are likely key factors influencing variations.(iii)Although street tree density could partially compensate for the loss of large old trees,the protection of such trees is important because of their close associations with key ecosystem services,such as total carbon storage.To maximize the value of street trees in promoting urban sustainable development,trade-offs among multiple ecosystem services should be integrated within the overall planning process and adjustments of planting regimes.展开更多
文摘Four kinds of plant materials (astragalus, azolla, rice straw and water hyacinth) were allowed to decompose for 10 years in two soils with different mineralogical characteristics in fields under upland and submerged conditions. Greater amounts of C and N from azolla were retained in soils throughout the 10-year experimental period compared to those from the other plant materials. The residual C Of all the plant materials in the two soils under upland conditions mineralized st rates corresponding to half-lives between 4.4-6.6 years,while the corresponding figures for thine under submerged conditions were between 6.5-13.1 years. Minerallization of residual organic N followed the same pattern as residual C. Compared to residual C, however, the mineralization rates of residual organic N in most cases were significantly lower and the percentages of added N regained in sons were higher. More N from plat materials was retained in the yellow-brown soil than in the red soil, but no consistent differences in the amounts of C from plant materials and in the mineralization rates of both residual C and residual organic N between the two soils could be found.
基金Funding for this study was provided by the National Natural Sciences Foundation of China(32130068,32171665).
文摘Urban afforestation is an important strategy for promoting sustainable urban development.In cities where large new green spaces are not available,the planting of curbside trees is deemed to be an important afforestation strategy.However,variations in the ecosystem services provided by street tree assemblages across socioeconomic gradients have been unexplored.We examined such variations in ecosystem services provided by street tree assemblages along an urban–suburban continuum.Our findings were as follows.(i)Not all ecosystem services showed increasing trends along the urban–suburban continuum.Some ecosystem services at the street tree assemblage level,such as air purification and rainfall interception were prominent in areas of high urbanization intensity.(ii)Diverse ecosystem service trends were found in relation to differential characteristics of street trees assemblages.Structural properties of street tree assemblages,such as tree density and age structure,are likely key factors influencing variations.(iii)Although street tree density could partially compensate for the loss of large old trees,the protection of such trees is important because of their close associations with key ecosystem services,such as total carbon storage.To maximize the value of street trees in promoting urban sustainable development,trade-offs among multiple ecosystem services should be integrated within the overall planning process and adjustments of planting regimes.
