Abstract:

To investigate the effects of different nitrogen application rates on the growth and development of greenhouse-grown cigar wrapper tobacco and the quality of the cured leaves, three nitrogen application levels were set: 150 kg/hm² (N1), 165 kg/hm² (N2), and 180 kg/hm² (N3). Using ‘Haiyan 101’ as test material, the study examined the impact of these treatments on agronomic traits, dry matter accumulation, and the post-curing quality of the middle leaves, including their appearance, physical properties, chemical composition, and sensory evaluation. Results showed that as the nitrogen application rate increased, the plant height gradually increased, the stem circumference thickened, and the leaves expanded; the accumulation of dry matter in roots, stems, and leaves also increased, with the proportion of dry matter in the leaves increasing relative to the whole plant; the identity, oil content, color uniformity, vein thickness, and green impurity index of the wrapper leaves initially increased and then decreased; the leaf length, width, single-leaf weight, and balanced moisture content first increased and then decreased, while the leaf thickness, pull strength, leaf density, and stem content gradually increased; the contents of total nitrogen, nicotine, starch, and protein significantly increased, whereas the total sugar and reducing sugar contents first increased and then decreased; the aroma quality, sweetness, and burning characteristics initially improved and then declined. Under greenhouse cultivation conditions, the wrapper leaves treated with 165 kg/hm² of nitrogen exhibited desirable appearance, physical properties, chemical composition, and sensory evaluation, meeting the quality standards for cigar wrapper tobacco. Therefore, it is recommended that 165 kg/hm² should be considered as the optimal nitrogen application rate for greenhouse-grown cigar wrapper tobacco. This study provides a scientific basis for the high-quality production of greenhouse-grown cigar wrapper tobacco in Wuyishan and similar ecological areas. In the future, the synergistic effect of nitrogen fertilizer and other nutrients and the regulation mechanism of nitrogen metabolism can be further studied.

Key words: nitrogen application rate, greenhouse cultivation, cigar wrapper, growth and development, tobacco leaf quality, dry matter accumulation, sensory quality