Effects Of Soil Acidity Adjustment On Growth,Yield And Quality Of Flu-cured Tobacco

Since the introduction of long-term rotation and the extensive application of pHysiological acidic fertilizer, Pingtang county has formed a large area of strong acid soil. To solve this problem, combination of pot experiment and field test were used to study the methods of soil acidity adjustment.The main results were as follows:1. Correlation between pH value and nutrients in soil of the flue-cured tobacco growing areas of Pingtang CountyThe pH average of flue-cured tobacco growing soil was5.97±0.80, the range was4.41-8.21, and the coefficient of variation was13.40%. Samples of low pH (pH<5.5) accounted for33.85%of the total sample; samples of the most suitable pH (pH between5.5and6.5) for flue-cured tobacco growth accounted for43.85%of the total sample. The correlations between pH and organic matter, alkali hydrolysable nitrogen (N), potassium (K2O) and total potassium (K) were positive, and the correlations between pH and available pHospHorus (P5OＯ2) and total pHospHorus (P) were significant negative, the contents of nutrient were varied greatly in different pH groups.2. Effects of soil acidity adjustment on growth and quality of flu-cured tobacco(Pot experiment)The results of pot experiment showed that when the soil pH were adjusted to5.4-6.9, plants had better agronomic characters and root growth, and high utilization efficiency of the absorption of N, P, K, Ca, Mg and trace elements. When the soil pH were adjusted to5.4-6.4, the component contents were appropriate, and the ratios of total sugar and nicotine, total nitrogen and nicotine, potassium and chloride were more appropriate, conforming to the standard of superior flu-cured tobacco.The results of field experiment showed that when the lime amount was20-60kg/mu, tobacco had better agronomic performances, and when the lime amount was100-120kg/mu, the soil pH was high (>7.5), and the tobacco had poor growth. Liming could effectively suppress the occurrence of root-stem diseases, and the trend of the disease occurrence was inversely proportional to the amount of lime. When the lime amount was20-40kg/mu, the tobacco had the highest yield, price and yield value, but excessive liming (100-120kg/mu) reduced economic efficiency. When the lime amount was20-60kg/mu, the component contents were appropriate, and the ratios of total sugar and nicotine, total nitrogen and nicotine, potassium and chloride were more appropriate, conforming to the standard of superior flu-cured tobacco.According to the results, when the lime amount was20-40kg/mu, the tobacco had better growth, higher economic efficiency and good quality.