Study On Soil Acidification Trend Of Tea Planting In Guizhou Province

This study takes the tea-planting soil profile in Guizhou Province as the research object.Through sampling investigation and laboratory analysis,the acidity index of the tea-planting soil at different levels（0-20cm,20-40cm,40-60cm,60-80cm,80-100cm）To determine and analyze the acidification characteristics of tea-planting soil profile,and then explore the factors affecting the acidification trend of tea-planting soil profile,in order to provide a scientific basis for the improvement of soil profile acidification in tea planting areas in Guizhou Province.The main findings are as follows:（1）The p H of the tea planting soil in the study area ranges from 0-20cm soil layer to80-100cm soil layer.As the depth of the soil profile deepens,the p H of the tea garden soil increases;the minimum p H value is 3.85 and the maximum value is 5.19,The average value changes in the range of 4.31～4.56,which belongs to strongly acidic soil;in the 0-100cm soil layer,the p H variation coefficient of tea garden soil first increases and then decreases.In the 0-100cm soil layer,the exchangeable acid content of the soil gradually decreases with the deepening of the soil layer.The exchangeable acid content of the 0-20cm soil layer is greater than the 80-100cm soil layer;the 0-100cm soil layer,the exchangeable aluminum varies The deepening content of the soil layer shows a gradual decrease;the exchangeable acid and exchangeable aluminum variation coefficients of tea-planting soil both show a tendency to increase with the deepening of the soil layer;in the 0-100cm soil layer,the exchangeable aluminum in the tea garden soil profile The ratio of exchangeable aluminum to exchangeable acid varies from 92.19%to 94.66%.The higher the soil acidity,the greater the ratio of soil exchangeable aluminum to exchangeable acid.In the0-100cm soil layer,with the deepening of the soil layer,the organic matter content of the tea garden shows a decreasing trend.（2）The cation exchange capacity of tea-planting soil in the study area is in the 0-100cm soil layer.As the soil depth of the soil profile increases,the CEC of the tea-planting soil shows a decreasing trend.The cation exchange capacity of the 0-20cm soil layer is significantly higher than 80-100cm soil layer;in the 0-100cm soil layer,as the soil depth of the soil profile increases,the total exchangeable base of the tea soil profile first increases and then decreases;in the0-100cm soil layer,with The soil depth of the soil profile increases,and the exchangeable calcium in the tea-planting soil profile shows a decreasing trend;the exchangeable magnesium content in the 0-100cm soil layer has no obvious change trend;the 0-100cm soil layer,the soil exchangeable potassium content in the study area generally varies with The depth of the soil layer increased and showed a downward trend.The exchangeable potassium in the 0-20 cm soil layer was significantly higher than that in the 80-100 cm soil layer（P<0.05）,and it accounted for 42.39%of the entire section.In the 0-100cm soil layer,the ratio of exchangeable calcium and magnesium to the total exchangeable base ions fluctuates between 86.06%and 97.20%.Exchangeable calcium and magnesium are the main part of exchangeable base ions.The ratio of exchangeable calcium to exchangeable calcium and magnesium in the 0-100cm soil layer fluctuates between 65.63%and93.89%.Exchangeable calcium is the main part of exchangeable calcium and magnesium.The content of exchangeable base ions showed the rule of Ca²⁺>Mg²⁺>K⁺>Na⁺.（3）The acid-base buffer curve of the 0-20cm soil layer of tea planting soil is generally milder than that of the 20-100cm soil layer,and the slope of the curve is relatively small.On the whole,the acid-base buffer curve of the 0-20cm soil layer of tea planting soil is higher than that of the20-100cm soil layer.The buffering performance is strong;the p H is increasing,and the rate of p H change is getting larger and larger;in the 0-100cm soil layer,as the soil depth of the soil profile increases,the acid-base buffering capacity of the tea planting soil shows a decreasing trend.The acid-base buffer capacity of the 0-20cm soil layer is higher than that of the 80-100cm soil layer;the acid-base buffer curves of the tea planting soil between different soil layers are all in an"S"shape,which can be divided into three stages,and tea planting between different soil depths The change trend of the soil acid-base buffer curve is similar.The soil p H in the first stage of the tea planting soil profile is less than 3.0,the soil p H in the second stage is between 3.0 and 5.0,and the soil p H in the third stage is greater than 5.0.（4）Factors affecting the acidification trend of tea-planting soil profile:Correlation analysis shows that there are different degrees of correlation between the basic physical and chemical properties of soil and soil acidity indicators.In the 0-20cm soil layer,p H is significantly positively correlated with exchangeable calcium and acid-reduced buffer capacity（P<0.01）,and is extremely significantly negatively correlated with exchangeable acid（P<0.01）;in the 20-40cm soil layer,PH and exchangeable calcium,exchangeable magnesium,base saturation are extremely significant positive correlation（P<0.01）;exchangeable acid and cation exchange capacity are extremely significant positive correlation（P<0.01）;in 40-60cm soil In the soil layer,p H and exchangeable acid are extremely significantly negatively correlated（P<0.01）;in the 60-80cm soil layer,p H and total nitrogen are significantly positively correlated（P<0.05）;in the 80-100cm soil layer,exchangeable acid and Exchangeable magnesium and base saturation are significantly negatively correlated（P<0.05）;in the 0-80cm soil layer,EA has a very significant positive correlation with SOM and CEC,and a very significant negative correlation with BS.In the entire section p H and ECa,EMG,BS are all positively correlated,and have a very significant negative correlation with EA.Redundant analysis shows that in the 0-40cm soil layer,BS and TP have an effect on the p H and exchangeable acid of the tea planting soil;in the 40-100cm soil layer,AN,p HBC,and EMG all have an effect on the p H and exchangeable acid of the tea planting soil.Impact:The 12explanatory variables（BS、SOM、TN、p HBC、TP、EK、EMg、ENa、AK、AN、ECa、CEC）in the entire soil profile explained the change rate of p H and exchangeable acid in the range of62.28%-90.87%.