The Research On Cultivation Method Of Directed Sowing Rapeseed In Rice Fields With Tillage Free

The study was conducted on experimental plots differing in the sowing time, sowing norm, sowing way and seed treatment about the cultivation method of directed sowing rapeseed in tillage-free rice fields. We observed the growth vigour of rapeseed and analysed the yield of different experimental plots to probe the best model that has the economic effects and the lowest cost among our experimental design. Our aim is to supply a reliable and scientific evidence for establishing the cultivation method of directed sowing rapeseed in tillage-free rice fields and to guide rapeseed production.The research achieved some results as the following:(1) Suitable sowing time. The sowing time is very important because the preceding crops are single or late season rice. After the harvesting, it is as early to sow rapeseed in the fields with tillage free as possible. So rapeseed seedling can make sufficient use of warm and light of later autumn and grow safely. Early seeding time could promote its vegetation growth.(2) Suitable sowing norm. There is a negative correlation between the individual and amount in the population. This mean is that a bigger population has a poorer individual; in the contrast a smaller population has a more powerful individual. So it is important to coordinate the relationship between the planting density and individuality. The results show that the best sowing norm is 200-250g per 667 square meters, the planting density is about 15,000 per 667 square meters. If the seeding time is later than October 20th, the sowing norm might be increased to 300g per 667 square meters, the suitable planting density is 20,000 per 667 square meters.(3) Suitable methods of seeding and seed treatment. The result shows that there is no significant difference on production among the different methods of seeding and seeds treatment. Directly sowing packaging rapeseeds in tillage-free rice fields covered subsequently with the rice straw is the optimum treatment. Increased yield ranged from 14.9%to 21.7%. The production of the experimental plots in the treatment of germination by pills with the packaging seeds is a little higher than the others. The packaging seeds didn't manifest dominance in the two experiments.(4) The economic effects are obvious. The demonstration test in Anxiang County shows the following results, among the several cultivation methods, the yield in tillage-free fields is 122.1kg per 667 square meters. Output value is 268.3 Yuan per 667 square meters (the unit price of rapeseed is 2.2 Yuan per kg), pure profit is about 135.6 Yuan. Output value and pure profit of the method are both exceed the whole county's average economic effects of tillage method or transplanting method. The method increases the yield of rapeseed by 32.1kg and 70.3 Yuan, 39.1kg and 85.7 Yuan, respectively for tillage method and transplanting method with tillage free. The pure profit of zero tillage is 80.3 Yuan and 70.7 Yuan more than that of tillage method and transplanting method with tillage free respectively.The above results show that the method of directed seeding rapeseeds in tillage-free rice field is not only simple but also high efficient, and can relieve labour and have good practicability, we believe that it has a bright and broad prospect.