摘要
分析比较了浙江慈溪耕作年限为50、100、500、700、1000、2000a的水稻土剖面和不同粒级复合体中有机碳的分布特征，并利用红外光谱技术，探讨了长期耕作对水稻土腐殖质结构和功能基团的影响。结果表明，耕作年限在50-2000a范围内，稻田耕作表层有机碳含量受耕作年限影响不大，随着耕作年限的增加，约30—60cm深度土层中有机碳含量有升高趋势。稻田土壤0-40cm土层和40-80cm土层有机碳储量变化幅度（△）随着耕作年限的增加逐渐下降，表明早期开垦的水稻土仍有很大的固碳潜力。100、500、1000a水稻土耕作表层中，〈2μm复合体的有机碳含量受耕作年限影响不大；随着耕作年限延长，〈2μm复合体有机碳分配系数不断增大，10-50μm复合体有机碳分配系数则呈下降趋势。100、500、700a水稻土胡敏酸的芳化度随耕作年限增加有所提高，500和700a水稻土胡敏酸的脂肪族-CH2-、-CH3基团含量要高于100a水稻土，胡敏酸的聚合程度基本上不受耕作年限影响。
Distribution of organic carbon was studied in soil profiles and organo-mineral complex,different in particle size,sampled from paddy fields varying in cultivation history,50,100,500,700,1000 and 2 000 years in Cixi City, Zhejiang Province. Effect of long-term cultivation on structure and functional groups of humus in paddy soils was explored with the aid of infrared spectrum （IR）. It seemed that cultivation history did not have much effect on organic carbon content in topsoil of the paddy fields. Organic carbon content of the soil layers,30 to 60 cm in depth increased gradually with the cultivation history, but the range （△） of the variation of soil organic carbon reserves between two paddy soil layers,0-40cm and 40-80 cm in depth respectively, decreased gradually. The findings show that paddy soils cultivated long ago still demonstrated a great potential for carbon sequestration. In the topsoil of paddy fields cultivated for 100,500 and 1 000 years,respectively,cultivation history had no significant effect on organic carbon content in organo-mineral complexes 〈 2 μm in particle size,while the abundance of organic carbon increased steadily in clay complex 〈 2 μm in particle size and declined in clay complexes, 10 - 50μm in particle size with cultivation history. Aromatization of humic acid in paddy soils cultivated for 100,500 and 700 years was enhanced with cultivation history. Aliphatic methylene （-CH2-） and methyl （-CH3） content of humic acid in paddy soils cultivated for 500 and 700 years was higher than in paddy soil cultivated for 100 years,and cultivation history had no effect on the extent of polymerization of humic acid.
出处
《土壤学报》
CAS
CSCD
北大核心
2008年第5期950-956,共7页
Acta Pedologica Sinica
基金
国家重点基础研究发展规划项目(2005CB121108)
国家自然科学基金重点项目(40335047)资助
关键词
耕作年限
水稻土
有机碳
有机无机复合体
红外光谱
Cultivation history
Paddy soil
Organic carbon
Organo-mineral complex
Infrared spectrum
