Influence of Humic Acid on Interaction of Ammonium and Potassium Ions on Clay Minerals

• Published in: Pedosphere Vol. 23; no. 4; pp. 493 - 502
• Main Authors: ZHANG, Wen-Zhao, CHEN, Xiao-Qin, ZHOU, Jian-Min, LIU, Dai-Huan, WANG, Huo-Yan, DU, Chang-Wen
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.08.2013; State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008 China; Key Laboratory of Agro-Ecological Processes in Subtropical Region, Institue of Subtropical Agriculture, Chinese Academy of Sciences,Changsha 410125 China%State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008 China%Key Laboratory of Agro-Ecological Processes in Subtropical Region, Institue of Subtropical Agriculture, Chinese Academy of Sciences,Changsha 410125 China
• Subjects: adsorption; cation exchange capacity; cations; clay; coatings; Fourier transform infrared spectroscopy; HA涂层; humic acids; illite; kaolinite; montmorillonite; nutrient availability; organo-mineral complex; organomineral complexes; potassium; soil amendments; surface area; 傅立叶变换红外光谱仪; 有机无机复合; 相互作用; 离子对; 粘土矿物; 腐植酸铵; 阳离子交换容量; illite; montmorillonite; adsorption; kaolinite; organo-mineral complex
• ISSN: 1002-0160; 2210-5107
• DOI: 10.1016/s1002-0160(13)60042-9

Interaction of ammonium （NH4＋） and potassium （K＋） is typical in field soils. However, the effects of organic matter on interaction of NH4＋ and K＋ have not been thoroughly investigated. In this study, we examined the changes in major physicochemical properties of three clay minerals （kaolinite, illite, and montmorillonite） after humic acid （HA） coating and evaluated the influences of these changes on the interaction of NH4＋ and K＋ on clay minerals using batch experiments. After HA coating, the cation exchange capacity （CEC） and specific surface area （SSA） of montmorillonite decreased significantly, while little decrease in CEC and SSA occurred in illite and only a slight increase in CEC was found in kaolinite. Humic acid coating significantly increased cation adsorption and preference for NH4＋, and this effect was more obvious on clay minerals with a lower CEC. Results of Fourier transform infrared spectrometry analysis showed that HA coating promoted the formation of H-bonds between the adsorbed NH4＋ and the organo-mineral complexes. HA coating increased cation fixation capacity on montmorillonite and kaolinite, but the opposite occurred on illite. In addition, HA coating increased the competitiveness of NH4＋ on fixation sites. These results showed that HA coating affected both the nature of clay mineral surfaces and the reactions of NH4＋ and K＋ with clay minerals, which might influence the availability of nutrient cations to plants in field soils amended with organic matter.