Chemical and spectroscopic characteristics of humic acid from a clay loam soil in Ontario after 52 years of consistent fertilization and crop rotation  

作　　者：Nan ZHAO Xixiang YANG Guocheng HUANG Yizhong LU Jing ZHANG Yuanyuan FAN Craig F.DRURYS Xueming YANG 

机构地区：[1]School of Envionmental Science and Enginering.Suen Nat sen Lniversity,Gnongzhow 510275,China [2]School of Chemistry,Guangzhou Key Labovatory of Analytical Chemistry fo Biomedicine,South China Normal University,Guangshou 510006,China [3]College of Resources and Environmental Sciences,China Agricnltural University,Bejing 100193,China [4]Key Latborafory of Enwinomental Namo Technologr and Heath Eect.Research Cemter for Ecr Ewinxumertad Sciences,Chimese Academy of Sciences.Berjing 100085,China [5]Harroge Re searh and Devebopmenr Cenre,Agrienilure and Agri Fod Canada,Harm,Onario NOR IG0,Camada

出　　处：《Pedosphere》2021年第1期204-213,共10页土壤圈（英文版）

基　　金：supported by the National Natural Science Foundation of China (No. 41571317);the Natural Science Foundation of Guangdong Province, China (No. 2018 A030313940);the Twelfth Five-Year National Science and Technology Support Project for Cycling of Agricultural Science and Technology Project, China (No. 2012BAD14B00)。

摘　　要：Long-term fertilization and crop rotation can influence both organic C sequestration as well as the C composition of soils and the more resistant organic C compounds contained in humic acid(HA). This study examined the effects of fertilization and cropping type(monoculture corn(MC) and Kentucky bluegrass sod(KBS) and corn-oat-alfalfa-alfalfa rotation(RC)) on the HA composition of soil from a 52-year field study in southern Ontario, Canada. Humic acid samples were extracted from soil, and elemental analysis, infrared spectroscopy, solid state 13C nuclear magnetic resonance spectra, and electron paramagnetic resonance methods were used to determine the influence of the cropping type on the characteristics of HA. Both fertilization and cropping type affected the chemical characteristics of HA. Fertilization led to a 5.9% increase in C, a 7.6% decrease in O, and lower O/C and(N + O)/C ratios in HA as compared to the corresponding non-fertilized treatments. Rotation resulted in a lower proportion of C(48.1%) and a greater(N + O)/C ratio(0.7) relative to monoculture cropping. Infrared spectroscopy analysis showed that HA contained more C-O groups in fertilized soil than in non-fertilized soil under MC and KBS. Fertilization increased the O-alkyl-C, phenolic-C, and free radical contents of HA relative to non-fertilization treatments. Rotation decreased the aliphatic and carboxyl groups and increased the O-alkyl, carbohydrate, aryl, and phenolic groups and free radicals, relative to MC and KBS. Both long-term crop rotation and fertilization dramatically modified the soil HA composition. Significant relationships were observed between the molecular composition of HA and soil organic C. Hence, humic acid characterization could be used as an indicator of the long-term sustainability of crop management practices.

关 键 词：CORN humification process infrared spectroscopy Kentucky bluegrass sod molecular composition soil organic C 

分 类 号：S153.622[农业科学—土壤学]