土壤学报2017，Vol.54Issue(3)：647-656,10.DOI:10.11766/trxb201611230392
长期施有机肥和化肥对潮土胡敏酸结构特征的影响
Effects of Long-term Application of Organic Manure and Chemical Fertilizer on Structure of Humic Acid in Fluvo-aquic Soil
摘要
Abstract
[Objective]Fertilization has become increasingly common to increase soil organic matter (SOM)content and improve soil fertility. Research suggests that fertilization promotes production of humic acids(HAs),one of the most important component of SOM. However little is known about the quantitative effects of fertilization on structural characteristics of HAs. Based on the long-term field fertilization experiment in Fegnqiu of Henan,effects of application of organic manure(OM),chemical fertilizer(NPK)and nothing(CK)on structure of HAs in fluvo-aquic soil were assessed. [Method]Soil samples were collected from the surface soil layers of three treatment plots,i.e. OM,NPK and CK,of a long-term winter wheat (Triticumaestivum L.)-summer maize(Zea mays L.)rotation experiment in Fengqiu,China. HAs were exhaustively extracted from the soil samples with a combined 0.1 mol L-1 NaOH and 0.1 mol L-1 Na4P2O7 solution and obtained through precipitation after acidification with 6 mol L-1 HCl. HF:HCl(1%:1%) solution was then used to purify the HAs obtained. In the end,the purified HAs were characterized with advanced solid-state 13C nuclear magnetic resonance(NMR)spectroscopy coupled with elemental analysis and isotopic analysis(δ13C). The NMR techniques included multiple cross-polarization/magic angle spinning (multiCP/MAS),dipolar-dephasing(DD),chemical-shift-anisotropy(CSA)filter and spectral editing of immobile CH2 and CH. [Result]Results show that long-term fertilization changed the element compositions,δ13C ratios and carbon functional groups of HAs,particularly significant in Treatment OM, and increased saturation degree,oxidation degree and polarity of HAs,but decreased condensation degree of HAs. The decrease of HAs in δ13C values indicated incorporation of new organic carbon into HAs. Advanced NMR techniques revealed that HAs in fluvo-aquic soil were composed predominantly of aliphatic compounds with alkyl being the highest in percentage(24.1%~26.3%). OCH3 and NCH signals both resonated aroundδ64~44,while the latter was prominent in proportion. Besides,the proportion of nonprotonated carbon was very low in anomeric and O-alkyl. Among the aromatics of HAs,they were dominated with protonated carbon in δ142~113,while only a little aromatic carbon existed in δ113~93,which cannot be detected with the routine cross-polarization/magic angle spinning(CP/MAS)NMR. It was also found that long-term fertilization reduced the percentages of COO/N-C=O and aromatic carbon of δ142~113,but increased the percentages of O-alkyl and OCH3. Moreover,application of organic manure also increased the proportions of aromatic C—O and NCH,but decreased that of alkyl.[Conclusion]In conclusion,all the findings in this study indicate that HA structure tends to be less hydrophobic with decreasing degree of decomposition. The application of either OM or NPK increases the content of carbohydrates in HAs. The application of OM also increases the contents of lignin and peptides,but decreases the content of lipids. The study also suggests that the advanced NMR techniques could provide great insight into HA structure and mechanisms of HA formation relative to fertilization pattern.关键词
胡敏酸/高级核磁共振/δ13C/元素分析/有机肥/NPK肥Key words
Humic acid/Advanced nuclear magnetic resonance/δ13C/Elemental analysis/Organic manure/NPK fertilizer分类
农业科技引用本文复制引用
徐基胜,赵炳梓,张佳宝..长期施有机肥和化肥对潮土胡敏酸结构特征的影响[J].土壤学报,2017,54(3):647-656,10.基金项目
国家重点研发计划项目(2016YFD0200107,2016YFD0300802)和现代农业产业技术体系建设专项资金(CARS-03)共同资助 Supported by the National Key Research and Development Program(Nos. 2016YFD0200107,2016YFD0300802)and the Earmarked Fund for China Agriculture Research System(No. CARS-03) （2016YFD0200107,2016YFD0300802）
