To study and document the occurrences and developmental influence of feeding ducks in rice paddies on rice sheath blight, and to provide the basis of rice sheath blight prevention and treatment in a rice-duck compounded system. Through the accounts and trials of feeding ducks in middle rice and late rice fields by the author, the results indicated that: in every 666.7m~2 middle rice paddy fields, 15～20 ducks weighing about 150 g each were fed, duck usage reduced the ratio by 56.0% in diseased hills of rice ...