| In this paper, study the Mengshan tea garden soil in Mingshan, Mengshan tea garden two different types of soil yellow soil and purple soil into different particle size of soil components using physical methods were (≤0.002mm,0.02-0.002mm,,0.2-0.02mm,,2-0.2mm), the use of the Elovich equation, the two-constant equation, parabolic diffusion equation and one diffusion equation K adsorption desorption kinetics data were fitted by the Langmuir, Freundlich and Temkin thermodynamic equation of isothermal adsorption processfitting. The study by exploring the components of the original soil and different grain size on the K+adsorption and desorption kinetics and thermodynamic characteristics, and analysis of all relevant factors, adsorption and desorption of the impact of tea garden soil and the grain size fraction in order to describe the macroscopic K+adsorption process and adsorption capacity, thus contributing to the understanding of the tea garden soil characteristics of K+in the tea garden soil, a variety of environmental behavior, provide a theoretical reference for the biological effectiveness of various forms of potassium in the further study of the tea garden soil. The results are as follows:(1)Soil organic matter, free iron oxide and CEC distribution in the original soil and different grain size, micro-aggregates to fine particle enrichment trend. The highest content of≤0.002mm grain size,2-0.2mm grain size followed by the lowest content in the0.2-0.02mm size. Calcium carbonate has the opposite trend, that is2-0.2mm grain size were the highest,0.2-0.02mm grain size Secondly, the lowest content of≤0.002mm grain size.(2) Original soil and different grain size fraction of K+adsorption capacity and adsorption retention in turn diminishing the following sequence:(≤0.002mm)>0.02-0.002mm> original soil>0.2-0.02mm2-0.2mm, and organic matter, freeiron oxide content of the CEC has a very significant correlation, and the purple soil of the original soil and particle size fraction to K+adsorption solid holding capacity was significantly higher than the yellow soil.(3) Use of kinetic method, different time gradient of the original soil and the grain size fraction of the body as time grows to K+adsorption and desorption volume increase, decreasing the adsorption capacity of the following sequence:(≤0.002mm)>0.02-0.002mm> original soil>0.2-0.02mm2-0.2mm, and the desorption amount of contrast, the following sequence in descending order:2-0.2mm>0.2-0.02mm> original soil>0.02-0.002mm>(≤0.002mm)and the purple soil is higher than the yellow soil, the desorption rate also increases. The original soil and particle size fraction on the adsorption characteristics of K+Elovich adsorption equations fit best, the desorption characteristics of the original soil and particle size fraction of K+desorption Elovich equation fitted best.(4) Use the thermodynamic method, the original soil and particle size fraction, as well as removal of organic matter and free iron oxide on K+adsorption and desorption increased with the increase of the K+initial concentration increases, but the particle size component adsorption capacitythe size varies, K+to the smallest particle size enrichment. Decreasing adsorption amount of the following sequence:(≤0.002mm)>0.02-0.002mm> original soil>0.2-0.02mm2-0.2mm, the desorption amount of contrast, the following sequence in descending order:2-0.2mm>0.2-0.02mm> original soil>0.02-0.002mm>(<0.002mm), and the purple soil above yellow, the desorption rate also increases. The original soil and soil particle size fraction, as well as removal of organic matter and free iron oxide adsorption properties of K+are fitted with the Freundlich equation best original soil and soil particle size fraction, as well as the removal of organic matter and free oxidation iron K+, desorption characteristics are fitted with the Freundlich equation.(5) After the removal of organic matter and free iron oxide particle group of the original soil and micro-aggregates of K+adsorption volume increased to some extent, in particular the added value≤0.002mm and0.02-0.002mm particle size and with equilibrium solution concentration increases. After the removal of organic matter and free iron oxide particle group of the original soil and micro-aggregates of K+desorption volume increased to some extent, and grain size growth law is consistent with the removal of organic matter and free iron oxide, and increase with increasing concentration in balanced salt solution, the desorption rate increased with increasing concentrations of The adsorption characteristics of the original soil K+after the removal of organic matter and free iron oxide with the Freundlich isotherm equation was best to remove organic matter and free iron oxide desorption characteristics of the original soil K+Freundlich isotherm desorption equation was the best. Basically consistent with the removal of organic matter and free iron oxide. |
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