The impact of water-fertilizer coupling on growth, development, yield and quality of flue-cured tobacco

【Objective】Tobacco is a cash crop grown in Western Henan Province, central China. This study experimentally investigates the effects of water-fertilizer coupling on its physiological and ecological characteristics, as well as its yield and quality.【Method】A pot experiment was conducted using tobacco variety Qinyan 96 as the model plant. It consisted of three treatments: no fertilization (CK), conventional fertilization used by local farmers (T1), and drip fertigation (T2, i.e., water-fertilizer coupling) that delivers soluble or liquid fertilizer into the root zone; each treatment had three replicates. Irrigation was performed at four key growth stages: the transplanting, early vigorous growth, mid vigorous growth, and late vigorous growth stage. During the experiment, we measured physiological-ecological traits including photosynthetic rate, stomatal conductance, chlorophyll content, and dry matter accumulation at different growth stages. After harvest, we measured the yield-related indices (total yield, output value, average price, proportion of premium-grade tobacco leaves) and quality-related indices (protein and starch contents).【Result】Water-fertilizer coupling significantly increased plant height, leaf numbers and leaf area. During leaf growth and development stages, water-fertilizer coupling significantly increased physiological traits such as chlorophyll content, photosynthetic rate, and stomatal conductance. Compared with T1, T2 increased the proportion of premium-grade tobacco by 19.08%. Compared with CK and T1, T2 increased tobacco yield by 9.11% and 1.92%, respectively, and starch and protein contents in tobacco leaves by up to 0.33% and 2.58%, respectively. 【Conclusion】Water-fertilizer coupling effectively improved the physiological and ecological traits of tobacco, thereby increasing its yield and improving its quality.