Historically, use of soil with a pH of 5.6 to 5.8 has been recommended for producing best quality burley tobacco. This recommendation for a relatively low pH resulted from the reported increases in the incidence of certain diseases, notably black root rot (Thielaviopsis basicola) and black shank (Phytophthora parasitica), in soils with pH greater than 5.8. Additionally, some researchers have reported undesirable chemical properties of cured leaf grown on soils that had been limed. However, workers at the Kentucky Agricultural Experiment Station generally have reported favorable effects from use of lime on both yield and quality of tobacco grown in soil that initially was acid. These apparent conflicting views may be attributed to differences in soil Properties, lack of disease resistant varieties, incidence of disease organisms, and other conditions associated with the production of different tobacco types. The low rates of commercial fertilizer, especially nitrogen, applied to tobacco prior to about 1950 may have resulted in the successful production of burley in soils of low pH due to the relatively low acid-forming potential of such rates.
Sims, J. L.; Atkinson, W. O.; and Wells, Kenneth L., "Relationship between Soil pH and Yield of Burley Tobacco" (1977). Agronomy Notes. 115.