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CORESTA Congress, Online, 2020, Agronomy/Phytopathology Groups, APPOST 08

Growth, nitrogen uptake and soil N2O emissions in flue-cured tobacco as influenced by drip fertigation strategy

MA Erdeng(1); GAO Tian(2); ZHANG Guangbin(3); XU Zhaoli(1); LI Junying(1); TONG Wenjie(1); Deng Xiaopeng(1)
(1) Yunnan Academy of Tobacco Agricultural Sciences of CNTC, Kunming, P.R. China; (2) College of Tobacco Science, Yunnan Agricultural University, Jinhei Road, Kunming, P.R. China; (3) State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, P.R. China

Fertilizer strategy mainly includes the time and rate of fertilization, which is the most important content in the crop fertilization regime. Considering the rapid expansion of the application scope of drip fertigation technology, a scientific strategy for fertigation is highly needed in the guidance of flue-cured tobacco production, in favour of nutrient management with both enhancing benefits and mitigating soil N2O emissions. A field experiment was carried out in flue-cured tobacco from 2018 to 2019 to study the effects of drip fertigation strategy on the growth, nitrogen uptake and soil N2O emissions. Three treatments in drip fertigation strategy were established, namely conventional strategy (CDF), average strategy (ADF), and optimized strategy (ODF), based on the treatments of no fertilizer application (CK) and conventional fertilizer application (CF). The results showed that dry matter accumulation, nitrogen uptake and tobacco leaf yield increased in various degrees, compared with that of CK. Nitrogen use efficiency and tobacco leaf yield increased in various degrees, while nicotine content of tobacco leaf decreased in various degrees as compared to that of CF. The effects of drip fertigation strategy on the growth, nitrogen uptake and soil N2O emissions was noticeable in various degrees. Dry matter accumulation rate at vigorous growing stage increased by 0.06 ~ 0.13 times, and on average, leaf area increased by 6.8 % ~ 86.4 %, nicotine content of tobacco leaf increased by 7.4 % ~ 16.5 %, nitrogen uptake of whole tobacco plant increased by 10.1 % ~ 19.8 %, nitrogen fertilization efficiency increased by 28.7 % ~ 66.8 %, nitrogen agronomic efficiency increased by 7.0 % ~ 94.1 %, total N2O emissions in tobacco field decreased by 10.0 % ~ 38.4 % (P < 0.05), and N2O emission factor decreased by 10.0 % ~ 37.8 % (P < 0.05), relative to that of CDF and ADF, respectively. Based on the nitrogen demands of flue-cured tobacco, the optimized operation promoted the formation of flue-cured tobacco leaf area and the absorption and utilization of nitrogen fertilizer. The strategy not only ensured the yield and nicotine content level of tobacco leaf, but also reduced the risk of soil nitrogen leaching and N2O emissions from the tobacco field. It is an integrated nutrient management method for drip fertigation in flue-cured tobacco production.