Abstract:

To explore the feasibility of alternative planting of rapeseed-middle rice mode for double-cropping rice mode in cadmium-contaminated rice area, a field experiment was carried out to study the growing process, yield, economic benefit, and cadmium(Cd) content between rapeseed-middle rice and double cropping rice mode in paddy field with moderate cadmium pollution in Xiangtan, Hunan province. The results showed that both double cropping rice and rapeseed-middle rice could be harvested before October 20th. The yield of early rice and late rice were 5233.7 and 6298.3kg/ha, respectively, and the yield of rapeseed and middle rice were 1875.5 and 7531.0kg/ha, respectively. The yield of middle rice was 43.9% and 19.6% higher than that of early rice and late rice, respectively. Compared with double cropping rice, the total cost of rapeseed-middle rice decreased by 13.5%, the total output value increased by 2.1%, the total net income increased by 42.6%, and the ratio of total net income to number of labours increased by 38.5%. The Cd contents in roots, stems, leaves, and grains existed clear difference among early, middle, and late rice, which showed the trend of late rice > middle rice > early rice. The Cd content of unpolished rice was between 0.43-0.82mg/kg, and the Cd content of rapeseed was 0.11mg/kg. In terms of planting season, yield, economic benefit, and Cd content in grains, the rapeseed-middle rice mode could be used as an alternative planting mode for double cropping rice in the double cropping rice area polluted by Cd.

Key words: Cadmium pollution, Double cropping rice, Rapeseed-middle rice, Alternative planting, Feasibility