Effects of alternate partial root-zone irrigation on water saving and quality regulating of flue-cured tobacco at different growth stages

In order to investigate the theoretical foundation of irrigation method for tobacco production with water saving and quality regulating, the effect of alternate partial root-zone irrigation (APRI) on leaf physiological characteristics, water use and main quality indices of flue-cured tobacco during different growth stages under two fertilization levels was studied in a pot experiment. Results showed that APRI could regulate stomatal opening, reduce stomatal conductance, transpiration rate and water consumption of flue-cured tobacco, thus APRI could reduce irrigation water and increase water use efficiency (WUE). Compared with conventional irrigation (CI), APRI treatment during different growth stages of tobacco saved irrigation water by 10.6% under lower fertilization and 7.1% under higher fertilization, respectively. APRI also increased tobacco WUE by 2.3% under lower fertilization. APRI significantly increased K, soluble sugar and protein contents and then improved the quality of flue-cured tobacco. Compared with CI, APRI increased K and protein contents by 19.9% and 7.1% under lower fertilization, and by 29.5% and 15.1% under higher fertilization. And APRI treatment during in the root extending stage increased soluble sugar content by 17.6% and reduced the nicotine content by 25.7% under lower fertilization, respectively. Thus APRI at the root extending stage was an efficient irrigation method for tobacco production with water saving and quality regulating under lower fertilization in this study.