Carbon Sink/Source Of Different Land Use Systems In Chongming Agricultural Park

CO₂-based greenhouse gases has become a hot issue of global emissions reductions, theaccumulation of CO₂in the atmosphere, changing the pattern of the global carbon cycle, carboncycle has become the focus of current research areas. For the implementation of carbon emissionreduction plan, every year China plants large-scale cultivation to increase the forest coverage rateto for terrestrial systems contribute to carbon sinks.China is a large agricultural country, whether the farmland ecosystem is carbon sinks or nothas been controversial. Agro-ecosystem carbon stock is the most active part of the terrestrialecosystem carbon stock. The construction of low-carbon agricultural park involves various formsof material circulation and migration between the various subsystems, not only the implantsystem but also woodland systems, farming systems, etc.Shanghai Chong Ming Agriculture Park was selected as study sites in this study. Camphorforest and ginkgo forest were selected as typical plantation, rice fields and raw vegetable fieldswere selected as typical planting for the study, Exploring carbon balance characteristics of eachsubsystem under different land cover between greenhouses and open field and from the measuresof paddy fields to forests supports the data of of construction of low-carbon agriculture park.Studies showed that:（1） In Cinamomum camphora forest, the annual carbon sequestration of wood layer was8.21t hm^-2, the annual carbon sequestration of litter was2.01t hm^-2, carbon emission of soilheterotrophic respiration was3.23tC hm^-2, the system total fixed6.99tC hm^-2per year,expressed as carbon sinks. In Ginkgo biloba forest, the annual carbon sequestration of wood layerwas7.47tC hm^-2, the annual carbon sequestration of litter was1.54tC hm^-2, carbon emission ofsoil heterotrophic respiration was2.74tC hm^-2, the system total fixed6.27tC hm^-2per year. Thetotal annual carbon sequestration of Cinamomum camphora forest was higher than Ginkgo bilobaforest.（2） The whole Oryza sativa Linn growing fixed5.28t C hm^-2, during the planting, carbonemission of soil heterotrophic respiration was3.1tC hm^-2, carbon source of manual managementwas1.03tC hm^-2. The rice field fixed1.16t C hm^-2, showed weak carbon sinks.（3） Open field Lactuca sativa throughout the growing period fixed0.38tC hm^-2, it’s higherthan the greenhouse Lactuca sativa which fixed0.36tC hm^-2. Carbon emission of soilheterotrophic respiration of open field was0.68t hm^-2while greenhouses was1.25tC hm^-2.Thecarbon sources of artificial was both0.33tC hm^-2.The open field released0.33tC hm^-2,whichwas lower than greenhouses0.92tC hm^-2,they were both carbon source.（4） Soil respiration is the most important soil carbon pathway. Soil heterotrophic respirationrate of farmland was always higher than plantations, mainly because that, the low canopy densitymakes soil temperature farmland rises quickly by the direct sunlight, and the application of fertilizers strongers soil microbial activity to release more CO₂. when building a low-carbon Park,agro-forestry can be taken to reduce canopy density and surface temperature of the soil, and thenweakening the soil respiration.（5）According to the current situation of Chongming island, the most appropriate measures ofadding carbon sinks is to improve the fertilization systems, especially organic fertilizer toincrease soil organic carbon content as well as vegetation carbon content. The area of plantationis far smaller than farmland and the stand age is short, so carbon sequestration capacity ofplantation is weak. The mainly carbon mobile carrier of Park is still farmland, how to takemeasures to reduce emissions and add carbon sinks accroding to farmland carbon flows iscurrently the most important issue, and also the most important part of building a low-carbonagricultural park.