Present Weed Situations And Chemical Weed Control Techniques In Sugarcane Fields Of Yunnan

Sugarcane is the main cash crop in the boarder and minority areas of Yunnan Province, but the yield of sugarcane is less than the average of nation for a long time, the main factor is damaging by weeds. According to the regulation of weed population occurrence, the important factor to bring it into effect is that to choose appropriate variety of herbicide and using technology.The paper introduces the convert "w" sampling method to investigate systematically the weed in the sugarcane field and to analysis the weed population and main damaging population. To make sure the regulation of weed occurrence with investigating by stages the weed species and quantity in sugarcane field. The calculating model of the ecology and economic threshold period is constructed by field experiment. To sort the good and inferior herbicide and make the technology project to apply in the sugarcane production by field experiment on herbicide effect and adopting faint comprehensive appraisal method. The following results are indicated:1. There were 95 species of weeds occurred in sugarcane field of Yunnan Province, among of them, 20 species is the dominant species, which formed 5 kind of weed communities damaging sugarcane.2. The fastigium of weed occurrence was 20-40 days after the new root planting or old root harvest in water sugarcane land, while 20-50 days after the rainy season begin in arid sugarcane land.3. The ecology and economic threshold period was about the 10.3-48% during the whole bearing period which after seedling period.4. Using 25 kinds of herbicide by experimenting in preventing and killing of weeds, the results indicated that single- and mixed- Ametryne and dinron get the best effect, then the metolachlor+MCPA-Na+ Atrazine, Metolachlor-atrazine,Acetocnor-cotrazine and Simazine , Atrazine, geyphosate, oxyfluorfen, paraquat are effective.5. To make a project to control the weed by herbicide in the sugarcane field, and get extension for 321500hm~2, which can control weed effectively by 80.3%, and increase sugarcane production of...