Study On The Cultivation Techniques Of High Yield And High Efficiency Of "Sparse Intercropping" In Rapeseed (Brassica Napus L.)

The development of rapeseed production in mountainous area is limited by geographical conditions.It is difficult to achieve mechanization of agriculture,resulting in difficulty in popularizing condensed direct-seeding planting in mountainous area.At the same time,the increasing shortage of labor and the increasing labor cost could improve production cost and reduce economic benefits.This situation has seriously affected farmers’ enthusiasm for rapeseed production and reduced the planting area.The above reasons resulted in low economic benefits for seedlings and transplants in this region.In order to change this situation,we must change the existing rapeseed planting modes and develop new planting patterns,so as to reduce the production costs and improve the economic benefits.In this study,Zhongyouza 12 and Yangguang 2009 were chosen as the experiment materials,the differences of growth and development characteristics,yield components and economic benefits between the sparse transplanting of rapeseed with condensed planting and the conventional transplanting were studied.Combined with intercropping,the principle and benefit of increasing production were discussed.The main conclusions are as follows:1.Sparse transplanting promoted the growth and development of rapeseed.With the decrease of planting density,the growth of individuals was not limited by the environment.Plant height,stem diameter,leaf number of main stem,SPAD value and dry matter accumulation were all higher than those of conventional transplanting and condensed planting.Dry matter accumulation of single plant was the most obvious difference.Dry matter weight of mature plant was 1021 g at the highest level,but leaf area index was slightly lower than two conventional treatments.Before flowering stage,the leaf area index of sparse transplanting treatments was significantly lower than that of conventional transplanting and condensed planting.After the flowering period,the difference between three treatments were not significant.At the same time,sparse transplanting can also promote the increase of the number of branches.The number of effective branches of D1 was 85,5.84 times and 10.04 times than that of D2 and D3,respectively.The average diameter of rape stems under D1 treatment was 36.22 mm,1.74 times and 2.30 times than that of D2 and D3,respectively.Compared with sparse transplanting,sparse intercropping can increase the LAI and reduce the light transmittance of rapeseed population,while the growth and development process of rapeseed was not affected by intercropping.Also,there were no significant difference in plant height,stem diameter,leaf number and dry matter weight in all critical growth stages,but the transmittance of population was lower than that of single cropping.Intercropping will not affect the growth and development of rapeseed,it can intercept more light energy,and can effectively utilize photo-thermal resource.2.Sparse transplanting can enhance yield by increasing the number of pods per plant.The yield of sparse transplanting was significantly higher than that of the other two treatments,and mainly depended on the increase of pod number per plant.As the number of branches increased,the number of pod could more than 3000,while the number of pod in main inflorescence increased by 200~300.The average yield was 3160.56kg/hm~2,which was 31.26% and 26.71% higher than that of conventional transplanting and condensed planting.Sparse intercropping could increase the pod number and main inflorescence pod,which increased by 10.2% and 16.7% respectively than those of sparse planting.However,the 1000-seed weigh and the yield per plant decreased slightly,resulting in the final yield of 127.5kg/hm~2 lower than that of the sparse planting,and the yield difference was not the significant level.3.The economic benefits of sparse intercropping were higher than that of sparse transplanting.By analyzing the input/output ratio of different planting methods,sparse transplanting can significantly reduce production costs and increase economic benefits.The sparse transplanting rapeseed could reduce the cost of labor.The number of labor in the whole growth period was 100 /hm~2,which could save 39.5 /hm~2 and 42.5 /hm~2 respectively.The yield of sparse transplanting was 9548.55 yuan/hm~2,and the input/output ratio was 2.03,which was significantly higher than the other two planting methods.Compared with sparse transplanting and sparse intercropping,the labor cost of intercropping was 4500 yuan /hm~2 than that of sparse transplanting.Because the intercropping could harvest a quarter of the mustard,and did not affect the growth of the rapeseed,the final economic benefit of the intercropping was higher than that of the sparse transplanting,which can increase the harvest of 4462.2 yuan /hm~2,compared to the sparse transplanting.Therefore,compared with conventional transplanting and condensed planting,sparse transplanting can reduce production investment,increase economic benefits and relieve labor shortage during the growth period of rapeseed.At the same time,the economic benefit of sparse intercropping was higher than that of sparse planting.There was a high promotion value in the mountainous area.