Seasonal Nutrient Contents in Grey and Non-grey Flue-cured Tobacco

Analysis of leaf samples at intervals between late June and early August of 1979 and 1980 indicated lower mean concentrations of nitrogen and potassium, and higher mean concentrations of iron and manganese in grey than in non-grey (normal) tobacco. In grey tobacco, the concentrations of potassium and iron were present in deficient and toxic levels, respectively, in the majority of the samples throughout the whole sampling periods. Although symptoms on leaves resembled those of iron toxicity, changes in intensity of grey symptoms during sampling were associated with severity of potassium deficiency.