Effects Of Tea Polyphenols And Organic Acid On Transformation Of Iron And Aluminumin In Tea Garden Soil

This experiment chooses tea polyphenol in the soil with different tea planting age in Mingshan County, Sichuan province, and the vertical distribution characteristics of various forms of iron and aluminum as the research objective, trying to make clear the mutual relation between the tea polyphenol accumulation and the transformation of iron and aluminum. Through the laboratory culture experiment, this paper also analyzes the affect of tea polyphenol and organic acid on the modal transformation of soil iron and aluminum. The research shows that:(1) The distribution characteristics of various forms of iron and aluminum in the soil with different tea planting age:the longer the tea planting age is, the less is the content of total iron and free iron on the soil surface because of the iron absorbing by the tea trees. There is a trend that in the soil layer lower than 0-20cm, the activated iron and complex iron content gradually increases with the age of tea planting. Observing from the section of the soil, there is a trend can be found that the content of total iron gradually decreases with the depth of soil layer. There is a trend that the content of free iron on soil surface is getting less with the age of the tea planting and this content of free iron increases at the beginning and then decreases with the depth of the soil. The active iron content in the tea garden soil with different age increases first and then decreases with the depth of the soil, and the complex iron content in the tea garden soil with different age decreases with the depth of the soil. Relevant analysis shows that there is a very obvious negative correlation between the total iron content and the depth of the soil(r=-0.636, p<0.01). With the age of tea planting, there is a trend that the total aluminum content decreases first and then increases, the free aluminum content increases first and then decreases, the activated aluminum and complex aluminum in the soil decreases. With the depth of the soil layer, the total aluminum content increase, and the free aluminum content decreases slightly in general, the activated aluminum and complex aluminum in the soil decreases. The increase of the soil organic matter collected in different time from the same plot and its PH is in accordance with the age of tea planting; they are in the similar trend that the PH and organic matter decrease with the depth of the soil layer. The content of total iron, free iron, active iron, complex iron, which are collected in different time, also varies similarly with the age of tea planting and depth of the soil layer. (2) The distribution characteristics of phenolic acid in the soil of different tea planting age:The total phenol content in various soil decreases with the depth of the soil layer. In general, the water soluble phenol in various soil increases continually with the age of tea planting and from the vertical direction, decreases with the depth of the soil layer. It shows statistically that the phenolic acid reaches at an apparent level (p<0.05) indicating that it can accumulate with the age of tea planting.(3) The mutual relation between iron and aluminum and phenolic acid in different tea planting soil:In the three-year tea planting soil, the content of total phenols, total iron, free iron, complex iron is significantly and positively correlated; the content of total phenols and total aluminum is significantly and negatively correlated; the content of total phenols and activated aluminum and complex aluminum is significantly and positively correlated; the content of total phenols and free aluminum is significantly and positively correlated; the content of total phenols and total iron is significantly and positively correlated; the content of water soluble phenols and total iron is significantly and positively correlated; the content of water soluble phenols and activated iron is significantly and positively correlated; the content of water soluble phenols and complex iron is significantly and positively correlated. In the five-year tea planting soil, the content of total phenols, total iron is significantly and negatively correlated; the content of total phenols and free iron is significantly and negatively correlated; the content of total phenols and activated iron is significantly and positively correlated; the content of total phenols and complex iron is significantly and positively correlated; the content of total phenols and free aluminum is significantly and negatively correlated; the content of water soluble phenols, total iron, free iron is significantly and negatively correlated; the content of water soluble phenols and activated iron is significantly and positively correlated. In the seven-year tea planting soil, the content of water soluble phenols and free iron is significantly and negatively correlated; the content of water soluble phenols and complex iron is significantly and positively correlated; the content of water soluble phenols and total aluminum is significantly and negatively correlated; the content of water soluble phenols and activated aluminum is significantly and positively correlated; The content of phenolic acid and the modal of iron and aluminum is apparently correlated especial in the three-year tea planting soil.The impact of tea polyphenol on the modal transformation of iron and aluminum and the content of phenolic acid:In the three kinds of soil, the phenolic acid content increases with the concentration of tea polyphenol and in purple soil the activated iron content increases slightly when being added 0.25% tea polyphenol but it apparently decreases when being added tea polyphenol with over 0.50% concentration, which indicates that tea polyphenol with low concentration can increase the content of activated iron while the one with high concentration can do the opposite. In yellow soil the content of complex iron shows a gradual increase tendency, apparently higher when being added tea polyphenol. The complex iron content of paddy soil increased slightly with the increase of concentration of tea polyphenol. In the three kinds of soil the content of activated aluminum and complex aluminum changes slightly but not obvious in different concentration.(4) The impact of organic acid on the modal transformation of iron and aluminum and the content of phenolic acid:Oxalic acid, a sort of low molecular organic acid, has no apparent impact on the content of phenolic acid when being added to the soil, and it also has no impact on the content of activated iron, complex iron, activated aluminum and complex aluminum. Humic acid is a kind of macromolecule. and the content of total phenols in paddy soil increases gradually with the concentration of humic acid, being stronger impacted by high concentration than that by low concentration. In purple soil the content of activated iron decreases apparently when being added to humic acid while the content of complex iron increases apparently with the concentration of humic acid. In paddy soil the content of complex iron increases slightly with the concentration of humic acid while the content of activated aluminm decreases slightly when being added to humic acid.