Study On Actual Development And Control Technique Of Weeds In Wheat Field Of Guanzhong Irrigation Area Of Shaanxi Province

The weed community and dominant species of wheat-field in Guanzhong irrigation area of Shaanxi province were diversification in recent years as a result of using chemical herbicides during long time in larger area. This paper dealing with the investigation for evolvement of the dominant species, the analysis of causation for the evolvement of the weed community, develop the field experiment for the herbicides and instruments and develop the integrated control technique for the dominant weed.1. The 37 species in the 17 family of the weeds is the harmful dominant species in wheat-field of Guanzhong irrigation field. There are six species of popular in distribution and serious in damage, including flixweed, burweed, Phleum paniculatum, procumbent speedwell, blind weed, corn gromwell, and the malignancy weeds including flixweed, burweed, chickweed, procumbent speedwell, candlegrass, annual ryegrass, Aegilops squarrosa.2. The disciplinarian and the reason for the evolvement of the weeds in the wheat field of Guanzhong irrigation area are definitude. The dominant species in 1970's are mainly broad leaf weeds including blind weed, corn gromwell, catchweed, and in recent years are conjunct species of broad leaf and gramineous weeds including Phleum paniculatum, Aegilops squarrosa, annual ryegrass, etc. The main reasons for the evolvement of dominant species in weeds community are introduction of seeds frequently, use of unique herbicides long period, simple farming system and extensive culture practices, fallback in using technique of herbicides, and loosen in integrated measures of agriculture.3. The preventive effect for weeds in wheat field can be increased by using WS-16 hand sprayer with the spray head in sector, and owing to the high attachment of herbicides to weeds, without running, emitting, dripping and leaking during the operation.4. Mesosuifuron , Derby, tribenuron-methy, thifensulfuron-methyl are the effective herbicides for control the weeds of wheat field in Guanzhong irrigation field, and without the risk of damage to wheat. The control effect are better in winter than in next spring withthe same content of the herbicides.5. The strategy and technique measures for integrated control of wheat weeds in Guanzhong irrigation area are presented basing on the disciplinarian and the reason for the evolvement of wheat weeds. Considering the environment and the biotic population, the best strategy for control the wheat weeds in irrigation field are integrating the agriculture practices, chemical herbicides, plant quarantine, and manual work for decreasing the damage of wheat weeds below economic threshold.