Relationship Between The Principal Chemical Components And The Ecological Factors Of Luoyang Tobacco-growing Areas

On the basis of the 7 main tobacco-growing counties in Luoyang, the ecological conditions including climate and the soil were analyzed, and by applying membership function and estimating weight values for each index by using the method of climate feasibility and soil feasibility were comprehensively evaluated. The ecological factors and the principal chemical components of flue-cured tobacco were also studied. Main results were as follows:1.The average temperature was 14.10℃in Luoyang tobacco-growing areas. And the temperature ranged 19.90℃to 27.30℃with the mean 24.76℃in growing season; the average temperature was a little low (18.50℃) at the root spreading stage, which between Brazil and America, Zimbabwe; the temperature (26℃) at the fast growing stage was higher than the quality tobacco region abroad; but the temperature (24.7℃) at the leaf maturity stage was in the feasible scale. The sunshine time of the growth duration after transplant was 85.97h, which was higher than the quality tobacco region abroad, and the ratio of sunshine hours was 39.48%; the available accumulated temperature was higher than Brazil and Zimbabwe, but lower than America. The rainfall during the different growth duration presented the similar trend of Brazil, and increased with the period of the root spreading stage-the fast growing stage-the leaf maturity stage; the average humidity after transplant was lower than the quality tobacco region abroad.2.The pH was a little higher, with the mean of (8.04±0.27), which was highest in Songxian; the organic matter content was (1.23±0.30)%, for 82.96% samples in the feasible scope, which was highest in Yichuan; the total nitrogen ranged 0.01% to 0.13%, with the average of (0.09±0.02)%, the available nitrogen, the available phosphorus, the available potassium and the organic matter were in the medium level, which took up 78.0%, 87.0%, 74.6%, 69.4% in the total samples. The comparison of the available nitrogen, the available phosphorus, the available potassium among the different tobacco-growing counties, the highest content counties were Yichuan, Yiyang, Ruyang, respectively; the calcium and magnesium content were in excess of the critical content, and it was not necessary to supply them for the tobacco growth, on the contrary, the calcium and magnesium were controlled to fertilizing into the soil; the average content of the available sulfur was (38.34±23.13) mg/kg, which was under 16mg/kg for 9.6% soil samples; the water-solubility content that above 45mg/kg was 7.8% of all the soil samples, and which was highest in Luoning; the average content of the available iron was (2.01±3.73)mg/kg, which was under the critical content of 2.5 mg/kg for 40% soil samples; the available manganese content, the available copper content, the available molybdenum content in soil were (4.00±4.57) mg/kg, (0.77±0.27) mg/kg, (21.16±7.36) mg/kg, respectively; the available zinc content in soil was (0.94±0.67) mg/kg, of which was in lack for 67.2% soil samples; the soil of Luoyang tobacco-growing region was in lack of available boron, and the available boron content was under the critical content for 96.0% soil samples with the average of (0.36±0.09) mg/kg.3. The total nitrogen content, the reduce sugar content, the nicotine content, the chorine content in Luoyang tobacco-growing areas were in fundamental extent, the potassium content was a little lower, the ratio of reduce sugar to nicotine, and nitrogen to nicotine were proper, the ratio of potassium to chorine had a large variation range. The nicotine content and the reduce content of part of the samples were a little higher; the mutual proportion of the chemical ingredients in tobacco leaves are in harmony fundamentally, but a few is less harmonious or unharmonious.4. The average of the climate feasibility index (CFI ) was (0.78±0.03), the differences were not large with the coefficient of variation of 4.87%, the climate feasibility was classified into two groups by K-means clustering method, the first group included Luoning, Yiyang and Yichuan, the second group was Songxian, Mengjin, Ruyang and Xin'an.5. The nutrient including the organic matter, pH, nitrogen, phosphorus, potassium and the water-solubility chorine, ect. , were chosen to definite the soil feasibility index (SFI) of Luoyang tobacco-growing areas, the average of the soil feasibility index was (0.562±0.138) with the coefficient of variation of 20.94%. The soil feasibility index was divided into five groups, the first class was SFI≥0.8, the second class was 0.6≤SFI<0.8, the third class was 0.4≤SFI<0.6, the fourth class was 0.2≤SFI<0.4 and the fifth class was SFI<0.2. The second and the third classes covered a large part of the whole, with the proportion of 67.54%. The soil of the seven counties were classified three groups by K-means clustering method, the first group included Songxian, Yichuang and Yiyang, the second group included Ruyang, Luoning, the third group included Xin'an, Mengjin. 6. The correlation analysis of the chemical components and the climate factors showed that, the correlation between the average temperature of the leaf maturity stage, the day-and-night temperature, the sunshine time during the growth duration after transplant and the chemical indexes was not significant, the different degrees of the heat conditions and the tobacco quality were founded. The nicotine and the total nitrogen content showed the trend of increasing with the temperature of the root spreading stage's, the fast growing stage's and the accumulated temperature≥10℃going up, but the ratio of reduce sugar to nicotine showed the trend of greatly decreasing. In addition, it had significant positive correlation between the nicotine content and the day-and-night temperature of the leaf maturity stage. The starch content and the ratio of reduce sugar to nicotine showed the trend of increasing with the accumulated temperature≥10℃going up, but the ratio of nitrogen to nicotine showed the opposite tendency; there was a declined tendency of the ratio of nitrogen to nicotine with the day-and-night temperature going up; the significant correlation was not found between the ratio of the potassium to chorine and the heat conditions. The correlation between the chemical components and the rainfall of the root spreading stage, the leaf maturity stage and the relative humidity in the field was not significant, but the rainfall of the fast growing stage had very significant or significant influences on the most of the chemical components; the very significant or significant negative correlation were found between the rainfall of the fast growing stage and the ratio of nitrogen to nicotine and the ratio of reduce sugar to nicotine.7. The stepwise regression analysis of the chemical components and the soil factors showed that, the three factors that appreciable impacted the nicotine content were the available potassium, the available nitrogen, the organic matter in turn; the total nitrogen content was effected by the total potassium, the organic matter, the available phosphorus and water-solubility chorine in turn; the ratio of nitrogen to nicotine was more influenced by the available nutrients, that was, the available nitrogen>the available phosphorus> the available potassium> the organic matter; the reduce sugar content was significantly effected by the soil factors of the organic matter, the total potassium, the available phosphorus and the water-solubility chorine, the nitrogen content had no significant influence; the ratio of reduce sugar to nicotine was more influenced by the available nitrogen, the total phosphorus, the organic matter; the potassium content effected by many factors such as the organic matter, the total nitrogen, the total phosphorus, the available phosphorus, the water-solubility chorine content; the ratio of the potassium to chorine was significantly effected by the soil factors of the total potassium and the water-solubility chorine.