Optimization Of Key Technical Parameters For No-tillage And Aerial Sowing Of Rapeseed Planting With Full Straw Returing

The no-tillage and aerial sowing of rapeseed planting with full straw returing is a newly developed rapeseed production mode in recent years,which has the advantages of saving labor,and improving the efficiency of light,temperature and resource utilization.As an emerging production mode,some key technical parameters need to be further optimized.In order to improve the key technologies in the no-tillage and aerial sowing mode of rapeseed in paddy field.Seven field experiments were carried out in Wuxue City,Hubei Province and Huangpi District,Wuhan City at the same time.Including the rapeseed sowing date test,rapeseed sowing rate test,rice stubble height test,fertilizer date test,fertilizer rate test,ditching date test and weed control method.By comparing the differences in rapeseed growth traits,yield and economic benefit of different treatments,the appropriate parameters of provide the basis for optimizing and perfecting the key technical parameters for no-tillage and aerial sowing of rapeseed planting with full straw returing.The main findings were as follows:(1)Sown the seeds 3 days before the rice harvest to 1 day after the harvest,the rapeseed has the best growth traits and the highest yield.When the rice was sown 3days after the harvest,the rapeseed yield in Wuxue showed a downward trend,and the rapeseed yield in Huangpi decreased significantly.Studies have shown that the suitable sowing date of rapeseed was from 3 days before rice harvest to 1 day after rice harvest.(2)The yield of rapeseed increases with the increase of sowing rate.When the seeding rate was 4.5-6.0 kg/hm~2,the stem diameter and plant height indexes of rapeseed at the budding stage were the best.But when the seeding rate was 7.5-9.0kg/hm~2,the yield of rapeseed was the highest and the economic benefit was the best.Therefore,the suitable seeding rate of rapeseed was 7.5-9.0 kg/hm~2.(3)With the increase of rice stubble height,yield,the nutrient accumulation and economic benefit of rapeseed increased first and then decreased.Before the flowering period of rapeseed,when the rice stubble height was 20-60 cm,the soil moisture content can be increased.The nutrient accumulation,yield and economic benefit of rapeseed were the highest when the height of rice stubble in Wuxue and Huangpi were 40 cm and 20 cm respectively.Therefore,this study recommends that the rice stubble height was 20-40 cm.(4)With the delay of the fertilizer date,the yield,the partial productivity of fertilizers and the accumulation of nutrients all showed a downward trend.Among them,fertilizer within 3 days after rice harvest has the highest partial productivity of fertilizer,the highest yield of rapeseed and the highest profit of rapeseed.Therefore,the suitable date of fertilizer was 3 days after the rice was harvested.(5)Increasing fertilizer rate,the growth traits,yield and economic benefit of rapeseed all tended to increase,while the fertilizer utilization rate gradually decreased.When the fertilizer rate was 600-900 kg/hm~2,the rapeseed yield was the highest.When the fertilizer rate was 750 kg/hm~2,the leaf area of rapeseed from seedling stage to budding stage was the largest,and the profit of rapeseed was the highest.When the fertilizer rate was 900 kg/hm~2,the fertilizer utilization rate was the lowest.Considering the sustainable development of the ecological environment,the recommended rate of slow-release fertilizer was 600-750 kg/hm~2.(6)The earlier ditching date,the higher the rapeseed yield and the greater the economic benefit.Among them,the rapeseed yield was the highest when the ditch within 3 days after the rice harvest.the rapeseed yield and economic benefits,the recommended ditching period was 3 days after the rice was harvested.(7)Enclosed weeding after rice harvest and stem and leaf weeding at four-leaf stage can both improve rapeseed yield,benefit of planting rapeseed,and nutrient accumulation of rapeseed.The rapeseed without weeding treatment was weak,the nutrient content of rapeseed was low,and the yield of rapeseed decreased significantly;at the same time,the weed biomass was more,and its weed biomass was 4.1 times and 2.9 times that of closed weeding and stem and leaf weeding.Therefore,the recommended weed control methods were stem and leaf weeding and closed weeding.In summary,the key technical parameters for no-tillage and aerial sowing of rapeseed planting with full straw returing were determined through research as follows:the suitable sowing date of rapeseed was 3 days before the rice harvest to 1day after the harvest,the suitable sowing rate of rapeseed was 7.5-9.0 kg/hm~2,and rice stubble height was 20-40 cm,the suitable fertilizer date was within 3 days after the rice is harvested,the suitable slow-release fertilizer rate is 600-750 kg/hm~2,the suitable ditching date was within 3 days after the rice was harvested,and the suitable weed control method were stem and leaf weeding and closed weeding.