关键词: N₂O, 烟草, 养分管理, 排放因子, 有机肥, 复合菌剂

Abstract:

Filed experiment of tobacco cultivation was conducted in Dali, Yunnan with five treatments, including no fertilizer (CK), conventional chemical fertilizer (CF), combined organic and chemical fertilizers (CM), organic fertilizer with water−soluble fertilizer (WS) and organic fertilizer with microbial agents (OM). High−frequency monitoring of N₂O flux from both ridges and furrows of tobacco field was conducted during the growth period, using the static chamber−gas chromatography method. Variation in N₂O emissions, emission intensity per unit yield and the influencing factors under different nutrient managements were analyzed, aiming to identify the emission characteristics and provide basic evidences for carbon emission accounting and low−carbon development in tobacco industry. Results showed that cumulative N₂O emissions under different nutrient managements ranged from 3.89 to 5.74 kg·ha⁻¹ during the growth period, with significant differences observed between CF, CM and OM treatments (P<0.05). Compared to CF, other treatments reduced N₂O emissions by 18.45%−32.29%. The N₂O emission factors varied from 0.31% to 1.60%, with the order from highest to lowest being CF, WS, OM and CM. Significant differences were found between CF and CM (P<0.05). N₂O emission intensity per unit yield varied from 1.31 to 2.17 kg N₂O·t⁻¹, with significant reductions of 39.81%, 33.42% and 37.58% in CM, WS and OM, respectively (P<0.05). Cumulative N₂O emissions were positively correlated with total and chemical nitrogen input, negatively correlated with carbon input, organic nitrogen input, and soil mineral nitrogen content, and not significantly correlated with plant nitrogen uptake. In conclusion, organic fertilizer substitution, along with water−soluble fertilizers and functional microbial agents, can effectively decrease N₂O emissions and enhance tobacco yield.

Key words: N₂O, Tobacco, Nutrient management, Emission factor, Organic fertilizer, Microbial agent