Carbon sequestration within millet phytoliths from dry-farming of crops in China  

作　　者：ZUO XinXin LU HouYuan 

机构地区：[1]Key Laboratory of Cenozoic Geology and Environment, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China [2]Graduate University of Chinese Academy of Sciences, Beijing 100049, China

出　　处：《Chinese Science Bulletin》2011年第32期3451-3456,共6页

基　　金：supported by the Strategic Priority Research Program of the Chinese Academy of Sciences (XDA05130602);the National Natural Science Foundation of China (4107113)

摘　　要：Phytoliths are noncrystalline minerals that form inside cells and cell walls of different parts of plants. Organic carbon in living cells can be occluded in phytoliths during plant growth. It has been documented that the occluded carbon within phytoliths is an important long-term terrestrial carbon reservoir that has a major role in the global carbon cycle. Common millet and foxtail millet have become typical dry-farming crops in China since the Neolithic Age. The study of carbon conservation within phytoliths in these crops could provide insights into anthropogenic influences on the carbon cycle. In this study, we analyzed the carbon content in phytoliths of common millet and foxtail millet. The results indicated that (1) common millet and foxtail millet contained 0.136% ± 0.070% and 0.129% ± 0.085% phytolith-occluded carbon (PhytOC) on a dry mass basis, respectively; (2) based on the mean annual production of common millet and foxtail millet in the last 10 years, the phytolith occluded carbon accumulation rate of common millet and foxtail millet was approximately 0.023 ± 0.015 and 0.020 ± 0.010 t CO 2 ha 1 a 1 , respectively; (3) assuming a similar phytolith occluded carbon accumulation rate as for common millet (the highest accumulation rate was 0.038 t CO 2 ha 1 a 1 ), this could result in the sequestration of 2.37 × 10 6 t CO 2 per year for the 62.4 × 10 6 ha dry-farming crops in China. Although there was a decline in the annual production rate and planting area of foxtail millet during 1949 to 2008, the total phytolith carbon sequestration rate was 7×10 6 t CO 2 within the 60-year period. However, phytolith occluded carbon has not yet been fully considered as a global carbon sink. Also, this carbon fraction is probably one of the best candidates for the missing carbon sink.Phytoliths are noncrystalline minerals that form inside cells and cell walls of different parts of plants. Organic carbon in living cells can be occluded in phytoliths during plant growth. It has been documented that the occluded carbon within phytoliths is an important long-term terrestrial carbon reservoir that has a major role in the global carbon cycle. Common millet and foxtail millet have become typical dry-farming crops in China since the Neolithic Age. The study of carbon conservation within phytoliths in these crops could provide insights into anthropogenic influences on the carbon cycle. In this study, we analyzed the carbon con- tent in phytoliths of common millet and foxtail millet. The results indicated that （1） common millet and foxtail millet contained 0.136%---0.070% and 0.129% ---0.085% phytolith-occluded carbon （PhytOC） on a dry mass basis, respectively; （2） based on the mean annual production of common millet and foxtall millet in the last 10 years, the phytolith occluded carbon accumulation rate of common millet and foxtail millet was approximately 0.023 - 0.015 and 0.020 ＋- 0.010 t CO2 ha-1 a-1, respectively; （3） assuming a similar phytolith occluded carbon accumulation rate as for common millet （the highest accumulation rate was 0.038 t CO2 ha-1 a-l）, this could result in the sequestration of 2.37 x 106 t CO： per year for the 62.4 x 106 ha dry-farming crops in China. Although there was a decline in the annual production rate and planting area of foxtall millet during 1949 to 2008, the total phytolith carbon se- questration rate was 7x106 t CO： within the 60-year period. However, phytolith occluded carbon has not yet been fully considered as a global carbon sink. Also, this carbon fraction is probably one of the best candidates for the missing carbon sink.

关 键 词：植物硅酸体 碳封存 作物 旱作 中国 全球碳循环 群众基础 二氧化碳 

分 类 号：S515[农业科学—作物学]