Study on the Optimum Seeding Rate with Direct Seeding of Medium Rice on Jinghan Plain

[Objective] The aim was to optimize the sowing rate of medium rice direct seeding on Jianghan Plain.[Method] The optimum sowing rate of fengliangyouxiang No.1was screened out by direct seeding trails of six different sowing rate form 22.5、30.0、37.5、45.0、52.5、60.0 kg/hm2.[Result] Seeding rate of rice influenced growth period and yield and economic coefficient and ralative economic output.When the seeding rate were 37.5 and 45.0 kg/hm2,the growth period were the longest.When the seeding rate was 37.5 kg/hm2.The yeild was significantly higher than the others and the economic coefficient was significantly higher than the treatment with the 60.0 kg/hm2 seeding rate.The relative economic output of 30.0 kg/hm2 was the highest.[Conclusion] The seedling amount had significant impacts on the growth period,agricultural property,economy property,yield and relative economy output.But there were differences of the optimum range of seedling amount of different properties.