黄菖蒲根际低分子量有机酸对土壤吸附氨氮的影响

Effects of LMWOAs of Iris Pseudacorus L.Rhizosphere on Ammonia Nitrogen Adsorption of Soil

根际低分子量有机酸是一类活性的化感物质,具有促进污染物迁移、转化与累积等重要的生态功能.本研究利用GC-MS技术,解析了黄菖蒲根际代谢物的组分特征与相对含量,通过模拟实验揭示了低分子量有机酸对土壤吸附氨氮的热-动力学的影响.结果表明:黄菖蒲根际代谢的不同种类低分子量有机酸均能促进氨氮吸附,但作用程度存在差异;氨氮在土壤中的吸附动力学符合Elovich方程与双常数方程,等温吸附均符合Langmuir和Freundlich方程的特征,其键能常数K L与有机酸解离常数pKa呈负相关;低分子量有机酸调控土壤吸附氨氮的机理主要是有机质活化作用.

Low molecular weight organic acid(LMWOA)of rhizosphere is a kind of active allelochemical,which has such important ecological functions as promoting the migration,transformation and accumulation of pollutants.The GC-MS technology was applied to analyze the composition characteristics and relative content of the rhizosphere metabolites of Iris Pseudacorus L..The simulation experiments were carried out to reveal the thermo-dynamic effects of the LMWOA on the soil adsorption of ammonia nitrogen.The results showed that different types of LMWOAs could promote the adsorption of ammonia nitrogen,but the degree of action is different.The adsorption kinetics of ammonia nitrogen of soil matches the Elovich equation and the double constant equation,and the isothermal adsorption complies with the characteristics of the Langmuir and Freundlich equations.Its bond energy constant K L is significantly correlated with the organic acid dissociation constant pKa,and the mechanism of LMWOA regulation of soil adsorption of ammonia nitrogen is mainly the activation of organic matters.