Influence of Variety and Soil Applications of Ca on Development of Ca Deficiency in Tobacco1
- G. F. Peedin and
- C. B. McCants2
Some commercial varieties of the flue-cured class of tobacco (Nicotlana tabacum L.) develop abnormalities of the buds and upper leaves which are typical of Ca deficiency. Utilizing varieties ‘Coker 254’ (susceptible) and ‘North Carolina 2326’ (slightly susceptible), greenhouse experiment was conducted to study varietal differences in Ca accumulation and distribution, and six field experiments were conducted to determine the effect of source and level of soil Ca applications on degree of symptom development. In the greenhouse, seedlings were transplanted in sand and supplied for 31 days with solutions containing 1, 75, or 150 ppm Ca. In the field experiments, rates of 0, 28, 84, or 168 kg/ha Ca (as CaSO4) were band-applied at transplanting; at one location and for two successive years, the variety and CaSO4 treatments were superimposed on rates of 0 and 1,121 kg/ha dolomitic limestone broadcast 2 months prior to transplanting. The soils used were classified as Typic and Aquic Paleudults and Typic Hapludults. In both the greenhouse and field, symptom expression of Ca deficiency was more pronounced on ‘C-254’ than on ‘NC 2326’ plants, but reduction of symptom expression with increasing levels of Ca was obtained only in the greenhouse. Maximum dry weight for ‘C-254’ was obtained with the 150 ppm Ca treatment, while the 75 ppm Ca treatment was sufficient for maximum growth of ‘NC 2326’. Conclusive evidence of varietal differences in Ca absorption was not obtained, but Ca concentrations in the apical tissues of ‘C-254’ were substantially lower than those in apical tissues of ‘NC 2326’, indicating that absorbed Ca was distributed less effectively in ‘C-254’ than that in ‘NC 2326’. Failure of ‘C-254’ to maintain adequate Ca concentrations in apical tissues may be associated with its comparatively greater accumulation of dry weight and absorbed Ca in leaf than stalk tissue. In field experiments, Ca deficiency symptom development was not related to level of exchangeable soil Ca, and was not influenced by the rates of CaSO, and/or dolomitic limestone used. Rather, symptom development was less pronounced at locations where plants were subjected to prolonged periods of moisture stress during vegetative growth, indicating that Ca deficiency is more likely to develop on immature plants that undergo periods of rapid growth.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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