Changes in soil carbon sequestration and soil respiration following afforestation on paddy fields in north subtropical China  

作　　者：Jun Cui Rongjuan Zhang Naishun Bu Huabin Zhang Boping Tang Zhaolei Li Lifeng Jiang Jiakuan Chen Changming Fang 

机构地区：[1]Jiangsu Provincial Key Laboratory of Coastal Wetland Bioresources and Environmental Protection,Yancheng Teachers University,Yancheng 224002,P.R.China [2]Coastal Ecosystems Research Station of Yangtze River Estuary,Ministry of Education Key Laboratory for Biodiversity and Ecological Engineering,Institute of Biodiversity Science,Fudan University,Shanghai 200433,P.R.China

出　　处：《Journal of Plant Ecology》2013年第3期240-252,共13页植物生态学报（英文版）

基　　金：Ministry of Science and Technology of China(2010CB950604);National Major Scientific and Technological Project in China(2010BAK69B14);National Natural Science Foundation of China(30970556,31170386);Doctoral Program of Higher Education of China(20093227110004);Key Project of the Shanghai Scientific and Technological Committee(10DZ1200700).

摘　　要：Aims Although many studies have reported net gains of soil organic carbon(SOC)after afforestation on croplands,this is uncertain for Chinese paddy rice croplands.Here,we aimed to evaluate the effects of affores-tation of paddy rice croplands on SOC sequestration and soil respiration(R).Such knowledge would improve our understanding of the efctive-ness of various land use options on greenhouse gas mitigation in China.Methods The investigation was conducted on the Chongming Island,north subtropical China.Field sites were reclaimed from coastal salt marshes in the 1960s,and soils were homogeneous with simple land use:histories.SOC stocks and R,levels were monitored over one year in a paddy rice cropland,an evergreen and a deciduous broad-leaved plantation established on previous paddy fields and a reference fal-low land site never cultivated.Laboratory incubation of soil under fast-changing temperatures was used to compare the temperature sensitivity(Q10)of SOC decomposition across land uses.Important Findings After 15-20 years of afforestation on paddy fields,SOC concentra-tion only slightly increased at the depth of 0--5 cm but decreased in deeper layers,which resulted in a net loss of SOC stock in the top 40cm.Seasonal increase of sOC was observed during the rice-growing period in croplands but not in afforested soils,suggest-ing a stronger SOC sequestration by paddy rice cropping.However,SOC sequestered under cropping was more labile,as indicated by its higher contents of dissolved organic carbon and microbial bio-mass.Also,paddy soils had higher annual R,than afforested soils;R,abruptly increased after paddy fields were drained and plowed and remained distinctively high throughout the dry farming period.Laboratory incubation revealed that paddy soils had a much higher Q10 of SOC decomposition than afforested soils.Given that tem-perature was the primary controller of R,in this region,it was con-cluded that despite the stronger SOC sequestration by paddy rice cropping,its SOC was less stable than in afforested s

关 键 词：land use soil organic matter(SOC) temperature sensitivity Q_(10) Chongming Island 

分 类 号：S15[农业科学—土壤学]