Effect of Bottom Leaf Removal and Fertilizer Rates on the Yield and Quality of Flue Cured Tobacco in Zimbabwe

C. Koga, D. Rukuni

The leaf position on a tobacco stalk determines leaf quality. Leaf quality is lowest for the bottom prime and lug grades, and is highest for the leaf and tip grades at the upper part of the plant. Experiments on removal of lower leaves to eliminate prime (P) and lug (X) grades date back to the nineties; and results then indicated that there was no merit in this agronomic practice. Recently, there were changes in market preferences, and merchants began demanding more of the upper leaves and paying a premium for these. This necessitated the re-initiation of leaf priming studies using two new higher yielding varieties at two sites for two planting dates (September and October). In these experiments, up to 10 bottom leaves were removed, and topping was done to reduce the number of remaining leaves to 14 against the standard of 18 leaves. In some treatments, additional fertilizers were applied to improve yield and quality of the remaining leaves. The highest value gain (~US$2 839) was obtained when six bottom leaves were pruned. However, an additional 400 kg/ha of high analysis fertiliser was applied at pruning, resulting in a yield increase of 1 104 kg/ha compared to the standard (no priming, no additional fertiliser). The same trend was obtained in the previous season (2014/15), where 421 kg/ha yield increase was observed when six leaves were pruned with similar fertiliser adjustments. The implications of these results will be discussed in this paper.