Abstract:
In order to obtain the field water management model of the rice field unit in the shrimp rice field after heavy rains,and to play the role of the shrimp rice field on the waterlogged water retention,a rice flooding experiment is carried out at the Yajiao Irrigation and Drainage Station in the Four Lakes Basin in Hubei. The experiment is carried out in a flooded pond. potted plants are used to simulate the flooding scenario of rice. A total of 7 treatments are set:shallow water short flooding(T1),shallow water intermittent flooding(T2),shallow water long flooding(T3),deep water short flooding(T4),deep water intermittent flooding(T5),deep water long flooding(T6)and conventional irrigation(CK). The results show that the flooding of rice jointing stage will promote the growth of the internode length and plant height of rice.Under the same flooding duration,the promotion effect is more obvious at high flooding depth than at low flooding depth;when the flooding depth is 40 cm,the plant heights of shorter flooded,intermittently flooded and long flooded rice increases by 2.9%,3.6% and 5.4% respectively compared with conventional irrigation. With the exception of shallow water short flooding treatment(T1),which slightly increases the yield,other flooding treatments would cause a decrease in rice yield. Under the same flooding duration,the yield of high flooding depth is less than that of low flooding depth when the flooding depth is 40 cm,the rice yields of short,intermittent and long flooding treatments are reduced by 4.3%,6.2%,and 13.1%,respectively compared with conventional irrigation. At the same flooding depth,the effects of intermittent flooding and short flooding on rice yield are similar. In terms of yield composition,the flooding treatment mainly reduces the number of grains per panicle and the seed setting rate. When the flooding depth is 40 cm,the number of grains per panicle and the seed setting rate are significantly reduced. In order to take into account both rice planting and shrimp farming,the water depth of 15~25 cm should be maintained when the rice of the shrimp rice field is flooding at the jointing stage or the paddy field should be flooded intermittently,and continuous flooding for a long time must be avoided.