关键词: 17β雌二醇, 17β雌二醇

Abstract: pH value of 488 soil samples taken from main tobacco-growing field in Xiangxi prefecture were tested in order to understand regional character of nicotine. The results indicated that the overall pH value was suitable for tobacco growing, the average value was 5.9, amplitude was 3.9-7.3, variable coefficient was 11.1%. The soil samples of suitable pH value accounted for 72.8%, the soil samples of“low”or“very low”pH value accounted for 26.8% , and of‘high’or‘very high’pH value accounted for 0.4% . The pH value of yellow brown loamy soil was significantly higher than that of paddy soil and red soil, and the order of pH value was: yellow brown loamy soil＞limestone soil＞yellow soil＞red dust soil＞red soil＞paddy soil, the pH value was in plaque distribution. In general, pH value in northwest was higher than that in southeast，the highest pH value was in Baojing County. Variance analysis indicated that the difference of pH value of tobacco-growing soil was highly significant, and pH value had significant positive correlation with the elevations; the correlation of pH value and the content of exchangeable magnesium and exchangeable calcium reached high significance; the correlation of pH value and available zinc was significantly positive; but there was no obvious correlation between the pH value and available potassium, water solubility boracic and available nitrogen.