Effects of Catch Crops on Tobacco Growth and Greenhouse Gas Emissions in Huanghuai Tobacco Area

The experiment was carried out in fluvo-aquic soil tobacco field to investigate the effects of catch crops on tobacco growth, greenhouse gas emissions and global warming potentials in Huanghuai growing area. Catch crops including smooth vetch (Vicia villosa var. glabrescens), triticale (×Triticale Wittmack) and rapeseed (Brassica napus) were sown in the winter fallow period, with the shoots used as fed and the residues returned to field. Analysis was performed for the differences of tobacco yields and soil CO₂ and N₂O emissions among treatments. Results showed as the followings. (1) The total biomass and tobacco yields in all of the three catch crop treatments were significantly higher than in winter fallow control, among which the vetch treatment achieved the highest, and followed by the rapeseed and triticale treatments subsequently. (2) The CO₂ emissions of the smooth vetch-flue-cured tobacco, triticale-flue-cured tobacco and rapeseed-flue-cured tobacco treatments exhibited slightly higher, significantly higher and lower than the winter fallow control, respectively. The N₂O emissions of the three catch crops-flue-cured tobacco were all significantly lower, of which the largest difference occurred between the smooth vetch-flue-cured tobacco and control. (3) The global warming potential of CO₂ from tobacco field displayed much higher than that of N₂O, among which the treatments of smooth vetch, triticale and rape reached 106.1%, 116.2% and 78.1% of the control respectively. In conclusion, the cropping mode of rapeseed-flue-cured tobacco can both improve the economic benefits of flue-cured tobacco, and reduce the soil global warming potential. The pattern of smooth vetch-flue-cured tobacco achieved the greatest flue-cured tobacco economic benefits without increasing soil global warming potential, thus the patterns of rapeseed or smooth vetch-flue-cured tobacco could be developed according to the local conditions.