| According to the data of field investigation for tea garden soil in Meng Ding mountain,the soil chemical properties and nitrogen mineralizations were analyzed under different cultivation years and different soil layers,through determination of chemical properties,mineralization-culturing experimentation.In order to provide a scientific theory foundation for reasonable amount of nitrogen and increase the utilization of nitrogen.The main results were as follows.(1) Changes of soil chemical properties character in different cultivation years:â‘ changes of soil basic chemical properties under different cultivation yearsAccording to the relevant analysis,cultivation years and soil pH value were highly significant negative correlation(a=0.01,r=-0.752**).Soil pH values in the region which between 4.61 to 5.20,declining with the planting years;while,soil nitrogen, organic matter,the base of nitrogen,phosphorus,potassium were very significant positive correlation(a=0.01,r=0.492** r=0.602**,r=0.552**,r=0.981** and r=0.978 **),their content were increased with the planting years.From the coefficient of variation,under different cultivation years,pH,available nutrient content were a weak variation;nitrogen content in the 5-year-old and 30 years old were weak variation,but middle variation in the other stage;organic matter content of 10-year-old middle variation,and the others were weak.According to soil nutrient level of classification,soil organic matter and nitrogen in rich,wereâ…£level;base nitrogen in rich wereâ…£Grade;AK in 5-year-old belonged toâ… grade,10-years and 20 years were belonged toâ…¡,30-years and 50-years were belonged toâ…¢grade,70-years was belonged to classâ…£;phosphorus in the 5-year-old and 10-year-old tea garden soil wereâ…¡,20-years in the classâ…¢soil,30 to 70 years were inâ…£level.â‘¡basic physical and chemical changes in different soil layerspH was increased with the up of soil depth;organic matter,available nutrient content in different soil planted years were rising trend,but in the same cultivation years, the content reduced as the soil deepening.According to high-quality high yield and high efficiency tea garden soil nutrient content standards,TN and AN were rich in various layers of Meng Dingshan tea garden;more than 90 percent of tea gardens achieved to high-quality tea garden soil organic matter content standards,organic matter content were riched;available phosphorus and potassium were Relatively in low levels.From the coefficient of variation,pH,TN and AN content were weak variation during different soil layers;organic matter,phosphorus and potassium content were a medium variant.(2) Soil nitrogen mineralization featuresâ‘ The correlation analysis,plant years and soil nitrogen mineralization,potential mineralization and net mineralization rate were a significant positive correlation(a=0.01, r=0.871**,r=0.871** and r=0.861**),With the length of the extension of cultivation,nitrogen mineralization,potential mineralization and net mineralization rate increased.From the coefficient of variation,under different cultivation years,soil nitrogen mineralization,potential mineralization and net mineralization rate,a weak variation;mineralization rates in the 5-year-old,30 years were weak variation, 10-year-old,20 years old,50-year-and 70-year-old were middle variation.â‘¡The correlation analysis,plant years and soil nitrogen mineralization,potential mineralization and net mineralization rate were a significant positive correlation(a=0.01, r=0.871**,r=0.871** and r=0.861**),With the length of the extension of cultivation,nitrogen mineralization,potential mineralization and net mineralization rate increased.From the coefficient of variation,under different cultivation years,soil nitrogen mineralization,potential mineralization and net mineralization rate,a weak variation;mineralization rates in the 5-year-old,30 were weak variation,10-year-old,20 years old,50-year and 70-year-old were middle variation.â‘¢Nitrogen mineralization and tea planting different years,while.different layers of organic matter,nitrogen related.Planting different years under the mineralization of organic matter and nitrogen,nitrogen positive correlation,the correlation coefficient were 0.970** and 0.990**;different soil nitrogen mineralization with organic matter,nitrogen positive correlation,the correlation coefficient was 0.998** and 0.999**.Soil nitrogen mineralization by the differences in nitrogen mineralization of nitrogen and organic matter and nitrogen ratio,C/N ratio,fertilizer,and other factors.
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