ABSTRACT.
Effects of effective microorganisms biochar-based fertilizer on photosynthetic characteristics and chlorophyll content of flue-cured tobacco under water-saving irrigation strtegies

Xiuneng Li1, Xiaohou Shao1*, Fuzhang Ding2, Youbo Yuan2, Rongqi Li1, Xu Yang1, Chao Gao1, and Qisong Miao1
 
Effective microorganism biochar-based fertilizer (EMBF) can improve the physiological properties of tobacco (Nicotiana tabacum L.) In this study, the irrigation and EMBF rates were applied as factors that influence the photosynthetic characteristics and chlorophyll content of tobacco. The experiment involved 12 treatments: CK1-CK3, T1-T3, T4-T6, and T7-T9; these four groups represented 0, 100, 300, and 600 g EMBF pot-1, respectively. Each group was irrigated at rates of 40, 80, and 120 L pot-1. When comparing with the control treatment CK, results showed that net photosynthetic rate (Pn), stomatal conductance (gs), intercellular CO2concentration (Ci), transpiration rate (Tr), and soil plant analysis development (SPAD) increased by 8.21%-107.03%, 18.78%-118.27%, 18.78%-118.27%, 7.24%-104.15%, and 3.47%-69.09%, respectively, after EMBF application. The Pn, gs, Ci, and Trat the growth and maturity stages were highly significant (P < 0.01) and positively correlated with EMBF application. The Pn, gs, and Trwere significant (P < 0.05) and positively correlated with irrigation, and Ciwas less affected by irrigation (P > 0.05). The SPAD value of flue-cured tobacco at three growing stages was highly significant (P < 0.01) and positively correlated with the irrigation and fertilization rates. The SPAD values at the growth and maturity stages were higher than those at the rooting stage by 46.73%-79.2% and 2.21%- 46.17%, respectively. Furthermore, the 80 L pot-1irrigation rate combined with 300 g EMBF pot-1is the best water and fertilizer combination. The results of this study might provide theoretical and practical guidance for growing flue-cured tobacco in production areas.
Keywords: Chlorophyll content, EMBF, flue-cured tobacco, Nicotiana tabacum, photosynthetic characteristics.
1Hohai University, College of Agricultural Engineering, 210098, Nanjing, China. *Corresponding author (hohaisxh@126.com).
2Institute of Tobacco Science in Guizhou Province, 550081, Guiyang, China.