Lower leaf removal and nitrogen application programs for flue-cured tobacco production
With a current global over-supply of flue-cured tobacco, tobacco producers in North Carolina have been encouraged to remove the lowermost leaves prior to harvest due to their low value in manufactured products. The objective of this research was to compare lower-leaf removal programs. Research was conducted in 2016 and 2017 to quantify the agronomic effects of three lower-leaf removal programs (0, 4, and 8 leaves plant-1) and the subsequent delivery of four nitrogen (N) application rates (0, 5.6, 11.2, and 16.9 kg N ha-1 above base recommendation). All treatment combinations were applied during the early flowering stage of growth (8-10 weeks after transplanting). Programs absent of leaf removal generally produced the highest cured leaf yield. The addition of 16.9 kg N ha-1 increased yield when compared to lower N application rates within the 4 leaf removal program. Nitrogen application did not affect yield in the 8 leaf removal program. Cured leaf value was greatest in the 0 leaf removal program ($US 10,131 ha-1) and was reduced in the 4 and 8 leaf programs by $US 1,611 and 2,645 ha-1, respectively. Lower-stalk positions were nearly eliminated in the 8 leaf removal program, while the 4 leaf removal program reduced their presence by more than 50 %. Ultimately, if these programs are to be encouraged or required by industry, the removal of 4 leaves per plant proved to be more practical when paired with additional N, due to moderate yield reduction and lower-stalk leaf production.