Growing Season Measurement of Petiole Sap Nitrate-N Concentrations in Burley Tobacco to Predict Yield and Tobacco Specific Nitrosamines in the Cured Leaf

摘要

Nitrogen is one of the most important inputs over which Burley growers have control. Nitrates accumulate in the leaf and form building blocks for bacteria that create tobacco-specific nitrosamines (TSNAs). Tobacco-specific nitrosamines are important to buyers because they constitute some of the most potent carcinogens in tobacco. During the course of a two-site, 3-year Burley tobacco-growing practices study, the Horiba Cardy meter readings of nitrate-nitrogen (N) in petiole sap were evaluated for predicting both yield and TSNAs from petiole sap nitrate-N analysis. Yield results did not correlate well with petiole sap nitrate-N at 6 weeks after harvest. Yield response to applied nitrogen was much less than expected and in some cases lacking at all and this probably accounts for the poor correlation observed. Correlation of petiole sap nitrate-N at week 8 from transplant and TSNA concentrations in the cured leaf were consistent and ranged from 0.39 to 0.86.