长期垄作稻田腐殖质稳定碳同位素丰度(δ^(13)C)分布特征  

Distribution characteristics of soil humus fractions stable carbon isotope natural abundance(δ^(13)C) in paddy field under long-term ridge culture

作　　者：唐晓红[1] 罗友进[2] 任振江[2] 吕家恪[2] 魏朝富[2] 

机构地区：[1]四川农业大学都江堰校区城乡建设学院,四川都江堰611830 [2]西南大学资源环境学院,重庆400716

出　　处：《应用生态学报》2011年第4期985-991,共7页Chinese Journal of Applied Ecology

基　　金：国家科技支撑计划项目(2006BAD05801);四川省教育厅青年科学基金项目(09ZB049);重庆市科委自然科学基金项目(CSTC;2009BB1115)资助

摘　　要：研究了四川盆地丘陵区连续16年垄(宽垄)作稻田土壤稳定碳库腐殖质组分的稳定碳同位素(δ13C)分布特征.结果表明:稻田土壤有机碳含量为宽垄作>垄作>水旱轮作.腐殖质碳以胡敏素为主,占土壤碳含量的21%～30%,提取碳以胡敏酸为主,分别占土壤有机碳和腐殖质的17%～21%和38%～65%.土壤有机碳的δ13C值介于-27.9‰～-25.6‰,20～40 cm和0～5 cm土壤有机碳δ13 C值之差约为1.9‰.土壤胡敏酸δ13 C值比土壤有机碳低1‰～2‰,更接近于油菜和水稻秸秆及根系的δ13C值.土壤富里酸δ13C值分别较土壤有机碳和胡敏酸高2‰和4‰.耕作层和犁底层胡敏素δ13C值分别介于-23.7‰～-24.9‰和-22.6‰～-24.2‰,δ13C值的变化反映了耕层中腐殖质的新老混合现象.各有机组分δ13C值递减顺序为:胡敏素>富里酸>土壤有机碳>稻草(油菜)残体>胡敏酸.长期水稻种植有利于增加土壤有机碳含量,同时,耕作方式影响土壤腐殖质δ13C在耕作层和犁底层中的分布格局.A 16-year field experiment was conducted in a ridge culture paddy field in the hilly region of Sichuan Basin,aimed to investigate the distribution characteristics of stable carbon isotope natural abundance（δ13C） in soil humus fractions.The soil organic carbon（SOC） content in the paddy field under different cultivation modes ranked in the order of wide ridge cultureridge culturepaddy and upland rotation.In soil humus substances（HS）,humin（HU） was the main composition,occupying 21%-30% of the total SOC.In the extracted soil carbon,humic acid（HA） dominated,occupying 17%-21% of SOC and 38%-65% of HS.The δ13C value of SOC ranged from -27.9‰ to -25.6‰,and the difference of the δ13C value between 0-5 cm and 20-40 cm soil layers was about 1.9‰.The δ13C value of HA under different cultivation modes was 1‰-2‰ lower than that of SOC,and more approached to the δ13C value of rapeseed and rice residues.As for fulvic acid（FA）,its δ13C value was about 2‰ and 4‰ higher than that of SOC and HA,respectively.The δ13C value of HU in plough layer（0-20 cm） and plow layer（20-40 cm） ranged from-23.7‰--24.9‰ and-22.6‰--24.2‰,respectively,reflecting the admixture of young and old HS.The δ13C value in various organic carbon fractions was HUFASOCrapeseed and rice residuesHA.Long-term rice planting benefited the increase of SOC content,and cultivation mode played an important role in affecting the distribution patterns of soil humus δ13C in plough layer and plow layer.

关 键 词：垄作 有机质 腐殖质 稳定碳同位素丰度( δ13C) 稻田 

分 类 号：S158[农业科学—土壤学]