Analysis On Characteristics Of The Physical And Chemical In Soil And The Microbial Environment In Rhizosphere Soil In Huai Yam Planting Areas In Wenxian

Based on the research of huai yam planting soil and huai yam, the soil physical and chemical characteristics, soil fertility are studied and analyzed; by the flame atomic absorption method, the content and the the correlation of Cu, Zn, Mn, Ni in the soil and the huai yam were determined and analyzed; by using colorimetric and volumetric methods, urease and catalase activity in soil was determined; by using the dilution plate method, the number of soil microbes was determined and made the analysis correlation between the two; the number of soil microbial changes and the changes of soil enzyme activities before and after planting were analysised, the results show that:(1) The porosity in the 0-20cm layer of the soil is highest, the average value is 52.83%; the soil bulk density in the 0-20cm layer of the soil is lower, it is higher in 20-40cm, 20-40cm layer of the soil; the solid content in the 0-20cm layer of the soil is lower, it is higher in 20-40cm, 20-40cm layer of the soil.(2)The average of organic matter content in huai yam soil samples is 17.9 g/kg, the average of total nitrogen is 0.95 g/kg, the average of total potassium is 25.4 g/kg, the average of total phosphorus is 0.78 g/kg; the average of organic matter content in wheat soil samples is 18.4 g/kg, the average of total nitrogen is 0.94 g/kg, the average of total potassium is 26.8 g/kg, the average of total phosphorus is 0.78 g/kg. The soil fertility is not key factors of influence the quality of huai yam.(3)The average content of Cu in the huai yam soil is 14.2 mg/kg, the average content of Zn is 164.3 mg/kg, the average content of Mn is 424.1 mg/kg, the average content of Ni is 21.3 mg/kg. The maximum of single factor of Cu is 0.172, the maximum of single factor of Zn is 0.692 , the maximum of single factor of Ni is 0.427, the trend is Zn>Ni>Cu. The contents of the three metal elements were not beyond the "soil environment quality standard (GB15618-95)", but the single factor pollution index of Zn is a little high, we should pay attention to it.(4) The average content of Cu in the huai yam is 8.36 mg/kg, the average content of Zn is 43.3 mg/kg, the average content of Mn is 6.4 mg/kg, the average content of Ni is 0.303 mg/kg; the single factor of Cu is 83.6%, the single factor of Zn is 86.6%, they are close to the standard limits, we should pay more attention.(5) The correlation coefficient of Cu, Zn content between the yam and the soil is 0.964 and 0.975 respectively, they have significant correlation; the correlation coefficient of Ni, Mn is 0.575, 0.047, they are not significant. (6) The catalase activity and urease activity of the soil are all significantly reduced after planting the yam, the catalase activity is 4.861 mL/g before planting, but 0.56 mL/g after planting; the urease activity is 0.5837 mL/g before planting, but 0.0552 mL/g after planting.(7) With the increasing of continuous yam planting, the microbial quantity order is two years soil>one year soil>wheat soil; bacteria accounted for its total 84.28%~ 93.35%, actinomyces accounted for its total 6.54%~15.64%, fungi only accounted for 0.07~0.11%. But with the increase of continuous cropping, fungi increased significantly, the order is two years soil>one year soil>wheat soil. The qutity of fungi in two years soil is 2.03 times of that in wheat soil, 1.79 times of that in one year soil.(8)In Huai yam rhizosphere soil, the correlation coefficient of urease activity and soil microbial numbers is 0.920, they are significantly correlated; the correlation coefficient of catalase activity and bacteria number is 0.025, its correlation is a little. The correlation coefficient of urease activity, catalase activity with actinomyces qutity is -0.164, -0.438, a weak negatively correlated.