Main research projects of Cheng Group.

・Elucidation of role of soil carbon cycle by using natural stable isotopes

Plants are grouped into C₃ plants or C₄ plants (and CAM plants). C₄ plants have higher photosynthesis efficiency and the ratio of ¹³C to ¹²C in all carbon compare to C₃ plants. Therefore, by using the ratio of natural stable isotopes abundance of plants (¹³C/¹²C), it can be understand how plants can derive carbon and circulates it in the soil. In our laboratory, we conduct experiment about photosynthesis carbon cycle and accumulation in rice as the C₃ plant and early water grass as the C₄ plant.

・Effects of global climate change by increasing CO₂ on crops of rice and soybean on their ecosystems

  Today CO₂ concentration of atmosphere is about 380ppm. However, it is estimated to be higher, about 485ppm−1000ppm, by the end of the twenty-one century. The global warming causes climate change and influence on food or plants production and also on soil ecosystem. Therefore, our laboratory is studying impact of higher CO₂ concentration of atmosphere and global warming on the plants and soil ecosystem by using crops of rice and soybean and so on, cooperating with National Institute for Agro-Environmental Sciences.

・_{The generating mechanism of C4 and N2O on vegetable-soil ecosystem and provision for their reduction}

The greenhouse effect gas is not only CO₂ but also CH₄ or N₂O and CFC(Freon).  The effect of CH₄ is about 20 times higher as that of CO₂, and N₂O is about 100 times higher. CH₄ is generated in rice fields and emitted into atmosphere through rice. On the other hand, N₂O is emitted from fertilizer in the fields. In our laboratory, we’re studying about the generating mechanism of CH₄ and N₂O and measure for its reduction.

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