Distribution Of Soil And Flue-Cured Tobacco Nutrients And Their Relationship Analysis

Based on the representative locations of different altitudes of Xuan'en and Xianfeng in Enshi tobacco-growing areas, 129 soil samples and 124 tobacco samples (contain Yunyan87, Yunyan85 and K326 which of three gradings of X2F, C3F and B2F) were selected to analyze the distribution of soil and flue-cured tobacco nutrients and their relationship. Main results were as follows.1. Distribution of soil nutrients in Enshi tobacco-growing regions was analyzed. For macroelements, the total nitrogen content and the hydrolytic nitrogen content in soil ranged from 0.07% to 0.39% and from 66.8 mg·kg^-1 to 233.9 mg·kg^-1, with the mean of (0.17±0.04) % and (131.69±30.97) mg·kg^-1 respectively. The variation coefficient of the total nitrogen content was a little higher than that of the hydrolytic nitrogen content. On the basis of the nitrogen content in soil, 129 samples can be divided into three groups with high, medium and low nitrogen content by using cluster analysis method, and samples involved in the group with low nitrogen content take up the 60.47% of the total. The comparison among the three soil depths showed the total nitrogen content and the hydrolytic nitrogen content were both highest in depth of 0～20 cm, and lowest in depth of 40～60cm. The phosphorus content in soil in Enshi tobacco-growing areas was low, with the average of (0.63±0.23) g·kg^-1 for the total phosphorus content and (16.88±12.73) mg·kg^-1 for the available phosphorus content. There existed high significant positive correlation between the total phosphorus content and the available phosphorus content, with correlation coefficient of 0.6353. Significant differences were found among the different altitudes and soil depths for the total phosphorus content and the available phosphorus content in soil, indicating the trends of high altitude> middle altitude>lower altitude, and the trends of 0～20cm>20～40cm>40～60cm. The potassium was rich with the average of (1.46±0.71) % for total potassium content and (225.97±104.08) mg·kg^-1 for the available potassium. With the altitude height going up, the total potassium content decreased, but the available potassium content increased. The comparison among different soil layers showed the total potassium content was highest in depth of 20～40 cm with the mean of (1.55±0.74) %, while the available potassium content was highest in depth of 0～20 cm with the mean of (223.60±105.72) mg·kg^-1. For mesne elements, the average content in soil of total calcium and exchangeable was 2124.60 mg·kg^-1and 1091.44 mg·kg^-1; Among 129 soil samples, 38.76% was calcium deficiency and 36.43% was on the high side. The calcium content showed the trends of high altitude>middle altitude>lower altitude among different altitudes, and the trends of 0～20 cm>20～40 cm>40～60 cm in different soil depths. The magnesium content in soil was low, with large coefficient variation, and significant differences were found among the different altitudes and soil depths for the magnesium content in soil.For trace elements, the available zinc content in soil in Enshi tobacco-growing areas was low, ranging from 0.17 mg·kg^-1 to 2.49 mg·kg^-1 with the mean of (1.00±0.51) mg·kg^-1 and the variation coefficient of 54.26%. 62.79% of 129 soil samples, for the available zinc content, were below the threshold of 1.0 mg·kg^-1 and part of the growing-areas were zinc deficiency. Significant differences were not found among the different altitudes, indicating the trends of high altitude>middle altitude>lower altitude. The available boron content in soil in Enshi tobacco-growing areas was low, with the mean of (0.32±0.15) mg·kg^-1, and 88.67% of soil samples was below the threshold of 0.5 mg·kg^-1, so boron deficiency had badly influenced the quality of flue-cured tobacco. Significant differences were found among the different altitudes and soil depths, indicating the trends of high altitude>medium altitude>lower altitude and 0～20 cm>20～40 cm>40～60 cm. The available copper content in soil in Enshi tobacco-growing areas ranged from 0.17 mg·kg^-1 to 9.88 mg·kg^-1 with the mean of (1.45±1.99) mg·kg^-1, and the soil samples took a major proportion for the available copper content of≥0.2～1.0 mg·kg^-1. The available copper content in soil was closely related to pH, when pH<5.5, the available copper content in soil was highest; when 5.5≤pH<5.9, the available copper content in soil was lowest; when pH≥5.9, the available copper content in soil was medium.2. Distribution of chemical components of flue-cured tobacco in Enshi tobacco-growing regions was analyzed. For total nitrogen, nicotine, phosphrous and potassium content, the total nitrogen content of flue-cured tobacco ranged from 1.58% to 2.95%, with the average of (2.13±0.33) % and the variation coefficient of 15.49%. Significant differences were found among the different cultivars, gradings, and altitudes for the total nitrogen content of flue-cured tobacco. The total nitrogen content of flue-cured showed the trend of K326>Yunyan85>Yunyan87 among various cultivars, B2F>C3F>X2F among different gradings, and high altitude > middle altitude > lower altitude among different altitudes. The comparison among the three altitudes showed, with the height going up, the nitrogen content in soil increased, but the total nitrogen content of flue-cured tobacco decreased. The nicotine content of flue-cured tobacco ranges from 8.18 g·kg^-1 to 42.25 g·kg^-1, with the mean of 22.80 g·kg^-1 and the variation coefficient of 36.42%. The samples with the nicotine content of 15 g·kg^-1 to 35 g·kg^-1 accounted for 66.94%. Significant differences are found among the different cultivars, gradings, and altitudes for the nicotine content of flue-cured tobacco. The nicotine content of flue-cured tobacco shows the trend of K326>Yunyan85>Yunyan87 among different cultivars, the trend of B2F>C3F>X2F among different gradings, and the trend of low altitude>middle altitude>high altitude among different altitudes. The phosphorus content of flue-cured tobacco was low with the mean of (1.68±0.32) g·kg^-1. Significant differences were found among the different cultivars and different altitudes for the phosphorus content of flue-cured tobacco, indicating the trends of Yunyan87>K326> Yunyan85, and the trends of high altitude>middle altitude>lower altitude. Though differences of the phosphorus content among different gradings were not significant, the phosphorus content increased with stalk positions going up. The average potassium content in flue-cured tobacco was (1.89±0.42) %, and showed the decreasing trend with the leaf positions going up. The average potassium contents of X2F, C3F and B2F were (2.14±0.49) %, (1.81±0.31) % and (1.73±0.36) %, respectively. The comparison of potassium contents among different cultivars indicated K326>Yunyan85>Yunyan87, and the potassium content of K326 showed significant difference with Yunyan87 and Yunyan85, but no significant difference was found between Yunyan87 and Yunyan85.For mesne elements of flue-cured tobacco, the calcium content of flue-cured tobacco was (1.80±0.63) %, and 48.28% of 124 flue-cured tobacco samples was in the comfort zone of 1.7% to 3.4%. Significant differences were found among the different cultivars and gradings, nor the different altitudes for the calcium content of flue-cured tobacco, indicating the trends of Yunyan87>Yunyan85>K326, the trends of X2F>C3F>B2F, and the trends of high altitude>middle altitude>lower altitude. The magnesium content of flue-cured tobacco was far below Brazil's (0.45%), with the mean of (0.28±0.14) %. There existed significant differences among various cultivars, different altitudes for the magnesium content of flue-cured tobacco, nor different gradings. They showed the trends of Yunyan87>Yunyan85>K326, the trends of X2F>C3F>B2F and the trends of high altitude>middle altitude>lower altitude respectively.For trace elements of flue-cured tobacco, the average zinc content of flue-cured tobacco was (29.18±7.99) mg·kg^-1, ranging from 15.40 mg·kg^-1 to 54.73 mg·kg^-1 and the variation coefficient of 27.38%. The coincident frequency for Brazil's (10.15～31.64 mg·kg^-1) was 63.79%. There existed significant differences among various cultivars, different altitudes for the zinc content of flue-cured tobacco, nor different gradings. They showed the trends of K326>Yunyan87>Yunyan85, the trends of high altitude>middle altitude>lower altitude, and the trends of B2F>C3F>X2F respectively. The average boron content of flue-cured tobacco was (15.65±7.26) mg·kg^-1, and lower than that of the national average level of 25.68 mg·kg^-1 and Brazil's (23.16 mg·kg^-1). The coincident frequency for Brazil's (14～31.06mg·kg^-1) was 50%. There existed significant differences among various cultivars, different gradings and altitudes for the boron content of flue-cured tobacco, they showed the trends of Yunyan87>K326>Yunyan85, the trends of B2F>C3F>X2F, and the trends of high altitude>medium altitude>lower altitude, respectively. The available copper content in soil decreased firstly, and then increased with altitude height going up. The available copper content in soil decreased with the soil depths deepening. The copper content of flue-cured tobacco averaged (6.62±6.74) mg·kg^-1, with amplitude of 1.26 to 34.30 mg·kg^-1, and coincident frequency for Brazil's (4.90～10.60 mg·kg^-1) was 29.31%. There existed significant differences among various cultivars, different gradings for the copper content of flue-cured tobacco, but not for the different altitudes. They showed the trends of Yunyan87>K326>Yunyan85, the trends of B2F>C3F>X2F, and the trends of lower altitude>high altitude>middle altitude, respectively.3. Relationship between soil nutrients and chemnical components of flue-cured tobacco was analyzed. The total nitrogen content of flue-cured tobacco demonstrated the increasing trend with the hydrolytic nitrogen content going up after the hydrolytic nitrogen content in soil was grouped.The regression equation was built between the nicotine content of flue-cured tobacco and the nitrogen content in soil, however, F-test showed the relationship was not significant at 5% level. Linear regression equation of y|^ =0.0026x+0.1224 was established between the phosphorus content of flue-cured tobacco ( y|^ ) and the available phosphorus content (x) in soil, with high significant correlation coefficient of 0.8582. When the available phosphorus content in soil was grouped and with its content increasing, the phosphorus content of flue-cured tobacco also increased. There existed significant regression relationship between the potassium content in flue-cured tobacco and the available potassium content in soil, with the equation of y|^ =0.0022x+1.4643, and r=0.8699*. The calcium content in soil and the calcium content of flue-cured tobacco were both increased with the altitude height going up, linear regression equation of y|^ =0.0008x+1.3986 was established between the calcium content of flue-cured tobacco ( y|^) and the exchangeable calcium content (x) in soil, with high significant correlation coefficient of 0.9409. When the exchangeable calcium content in soil was grouped and with its content increasing, the calcium content of flue-cured tobacco also increased. There was closely relationship between magnesium content in soil (x) and the magnesium content of flue-cured tobacco ( y|^ ), and positive regression equation of y|^ =0.0158x0.7637 was established between them. When the exchangeable magnesium content in soil was grouped and with its content increasing, the magnesium content of flue-cured tobacco also increased. The zinc content of flue-cured tobacco and the available zinc content in soil both increased with the altitude height going up. Moreover, the zinc content of flue-cured tobacco increased with the available zinc content going up. The boron content of flue-cured tobacco ( y|^ ) was closely related to the boron content in soil (x), linear regression equation of y|^ =7.1326x+22.705 was established between them, with high significant correlation coefficient of 0.7831. The boron content of flue-cured tobacco both increased with the altitude height going up and the boron content in soil increasing. The copper content of flue-cured tobacco and the available copper content in soil both increased with the altitude height going up. The copper content of flue-cured tobacco increased with the available copper content in soil increasing. In addition, the copper content of flue-cured tobacco and the available copper content in soil showed the similar trends in different pH scopes. There existed positive correlation between available copper content in soil and copper content of flue-cured tobacco.