Study On The Cultural Technology System Of Dry Direct Seeding In The Cold Area Of North Of China

In this paper, We study the technology of dry direct seeding planting at the growth disciplinarian of the weed in the dry direct seeding yield, the breed adapt to the dry direct seeding planting and the fertilizer and density in the cold area of north of China. The result showed that the weed community growth succession line is the relatively independent bimodal curve. The weed occurs two fastigium in the dry direct seeding yield. The first fastigium occurs at the 25d after seeding. The weed community is made of the weeds both water plants and the xeromorph plants. While the second fastigium is after 45 or 50d, and the water weeds is the most type. The amount of weed occurs during the second fastigium is 10% more than the amount of transplanting in this area. The growth character such as the growth duration, the effective tillering, the setting percent, the plant tall and the amounts of leaf etc. under the dry direct seeding is worse than under the transplanting. The yield of the dry direct seeding is lower the yield of the transplanting. We have selected three breed adapt the cold climate including the Longjing2,Longjing3 and Hejiang23. And the yields of three breeds was 5872kg,5783kg and 5778kg per hectare respectively. The nitrogen requirement under dry direct seeding is more than the requirement under transplanting while the utilization rate of nitrogen is lower than the utilization rate under transplanting during planting season. Under dry direct seeding, The rice character isn't effected obviously by the planting density. The most function by the plant density of dry direct is the basic seedling. When the nitrogen fertilizer was 180kg per hectare, the yield is the higher. The lower nitrogen fertilizer may accelerate the rice maturation while the higher nitrogen fertilizer may postpone the maturation. So this two amounts of application of nitrogen fertilizer is disadvantageous to accelerate the yield. The best scheme of nitrogen fertilizer and planting density is that the application of N is 180kg/ha and the amounts of basic seedling is 20 million per hectare. The yield is 6270kg/ha under this condition. The treatment of Paraquat+Butachlor can control the weeds during the first fastigium effectly, while the best treatment for controlling the weed during the second fastigium is Quinclorac+Bentazon. The synthetical control rate is more than 95 percent.