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Dynamics of crop yields and soil organic carbon
- IPCC had made it clear that the globle's climate warming effect was mainly due to greenhouse gases emission, especially from CO2(Bohannon 2007).
- The atmospheric carbon dioxide (CO2) concentration has been shown to be increasing at the annual rate of 0.5% due mainly to fossil fuel combustion and land-use changes since the 1850s(Ding, Meng et al. 2007).
- Farmland, as an important part of terrestrial ecosystem, occupied a large proportion of greenhouse emission(Petersen, Thomsen et al. 2010).
- Due to unreasonable fertilization, irrigation and so on, the content of SOC in the cropland soil had a massive decrease in the world and mainly in the way of CO2 into the atmosphere ( Lal, R et al).
- So there were a large number of studies about Soil organic-C sequestration (Manna, Swarup et al. 2007; Studdert, Monterubbianesi et al. 2011; Wang, Chen et al. 2011; Guo, Wu et al. 2012).
- It had aroused a growing concern of agronomists and ecologists for how to guarantee the production, increased soil organic matter content(Guo, Liu et al. 2010; Liu, You et al. 2010).
- China has a late start but fast pace about the research of soil organic-C sequestration and on the different regions and different types of soil carbon sequestration had an increasingly researches (Yin and Cai 2006; Li, Velde et al. 2011).
- However, more of studies lied in a dense region of China's agricultural development, such as the North China Plain, Loess Plateau and South of Paddy Soil(Hao, Fan et al. 2007; Li and Zhang 2007; Huang, Hu et al. 2009; Zhang, Wang et al. 2009; Ma, Yang et al. 2011; Niu, Hao et al. 2011).
- China's western region has very few researches especially in northwest oasis farmland about soil carbon sequestration.
- As the economic development of China, more and more money invest into the western of China (Agricultural Yearbook, 2000-2008).
- The oasis cropland had become the local pillar industries and to be the important exporter of agricultural products in China.
- Such as, oasis farmland produced one third amount of cotton in China and 8% in the word and rank first to be the most important commodity cotton base in China (Liu, Wang et al. 2000).
- Fruits and vegetables are also very important for the Chinese agricultural market.
- Secondly, Oasis farmland climatic conditions have characteristics significantly different from other places, such as drought, huge evaporation, intense mineralization of organic matter, etc.,(Luo, Yang et al. 2006; Sang 2009; Jiang, Hu et al. 2011; Liu, Duan et al. 2011; Yang, Chen et al. 2012).
- The yield and soil organic-C sequestration will have a unique feature.
- Thirdly, oasis farmland is in a process of development, continuously adjusted, unstable oasis agro-ecosystems due to the arable land expand and the huge fertilization input (Wang, Li et al.2002).
- So it is necessary to learn about the dynamics of yield and the inputs and outputs condition of soil organic-C.
- nanweo8pm
March 2013
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