| Dynamic assessment of the values of CO2 fixation and O2 release in the middle and lower reaches of Fenhe river Basin |
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| DOI：10.7606/j.issn.1000-7601.2018.02.35 |
| Key Words: the middle and lower reaches of Fenhe river Basin Net Primary Productivity (NPP) the values of CO2 fixation and O2 release dynamic assessment |
| Author Name | Affiliation | | ZHANG Jing | School of History and Tourism, Shaanxi University of Technology, Hanzhong, Shaanxi 723001, China
College of Tourism and Environment, Shaanxi Normal University, Xi'an, Shaanxi 710119, China | | REN Zhi-yuan | College of Tourism and Environment, Shaanxi Normal University, Xi'an, Shaanxi 710119, China | | ZHANG Jia-qi | College of Tourism and Environment, Shaanxi Normal University, Xi'an, Shaanxi 710119, China |
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| Abstract: |
| Based on light energy utilization model, Thisarticle calculated Net Primary Productivity. The photosynthesis equation was used to convert NPP to amount of CO2 fixation and O2 releasing and quantitatively computed the values of fixing CO2 and O2 releasing by using afforestation cost method and industrial oxygen generation method, in order to evaluate spatio-temporal dynamic changes of fixing CO2 and O2 releasing and provide some references for improving the regional ecological environment. The results showed: (1) the total amount of NPP increased by 18.3% during 2000—2010 in the middle and lower reaches of Fenhe river Basin. The amount of cropland NPP accounted for more than 50% of NPP in the study area and mainly distributed in the lower reaches of Fenhe River Basin, which is the main grain and cotton production area in Shanxi province. (2) From the point of fixing CO2 and O2 releasing, the quality of O2 releasing increased with the increasing of fixed CO2. The total value of fixing CO2 and O2 releasing increased to 552.24×107 yuan in 2010 from 467.38×107 yuan in 2000. There were a net increase of 84.86×107 yuan and an increasing rate of 18.16%. The total value of fixing CO2 and O2 releasing was “cropland＞grassland＞forestland＞other land” in orders from high to low. (3) From the perspective of the county administrative space, the value of NPP per unit area and the value of fixing CO2 and O2 release per unit area was the highest in Wanrong County, while the lowest was in Jiexiu City. Overall, the value of fixing CO2 and O2 release was higher in the lower reaches of Fenhe River Basin and the value of fixing CO2 and O2 releasing was lower in the middle reaches of Fenhe River Basin due to the rapid urbanization. In recent years, the implementation of the policy of returning cropland to forestland has improved the ecological environment in the study area. However, due to the limitation of water and heat conditions, forestland increase was not obvious i, and grassland increase was more significant. |
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