关键词: 稻虾共作模式, 播期, 还原性物质, 经济效益, 模式优化

Abstract: The different sowing date collocation with rice varieties of different growth stages was set to change the duration of soil flooding before planting rice.The soil reductive state of paddy field tillage was investigated, and the economic benefit of integrated rice-crayfish system was evaluated using the input-output method. The results showed that in integrated rice-crayfish system, changing rice sowing time, the total amount of soil reductive substances in paddy field did not change significantly, but the content of soil active reductive substances, active organic reductive substances and Fe²⁺ all increased with the flooding time prolonged, especially the content of Fe²⁺ increased significantly. Rice cultivation could significantly improve the soil reductive state of the tillage layer and reduced the soil Fe²⁺ content. After rice harvesting, the Fe²⁺ content of the three models tended to be the same, with no significant difference among them.With the delay of sowing time, the output value of rice gradually decreased, the cost of integrated rice-crayfish system increased, but the output value of crayfish increased significantly, and the comprehensive output value of integrated rice-crayfish system increased. However, with the delay of sowing time, there was less room for increase in the comprehensive output value of integrated rice-crayfish system.

Key words: integrated rice-crayfish system, sowing time, reducing substances, economic benefit, mode optimization