Study on the effiecency of weed control of Yubao herbicide in maize I. Study on effiecency of different dosage in different growth stage of maize

On the condition of continuous corpping of maize, the main weeds in the region include echinochloa crusgall (L.) beauv,digitaria sanguinalis(L.) Scop,chenopodium album L.,amaranthaceae,commelina communis L.,and cephalanoplos segetum (Bge.) Kitam etc, and the main harm are begotten by graminaceous weeds. The optimum using stage of Yubao herbicide are 3 and 4 leaf stage of maize in the region, and the optimum dosage is 900～1300 g ai/hm 2, and the efficiency of weed control is 90%. The efficiencies of the herbicide used on eliminating echinochloa crusgalli,chenopodium album L.,amaranthaceae,commelina communis L.,and rorippa palustris (Leyss.) Bess., are very good, and the efficiencies of it used on eliminating eigitaria sanguinalis(L.) Scop and cephalanoplos segetum (Bge.) Kitam are certain. The yield on the condition of using optimum dosage exceed that on the condition of manual weeding by 9.6% .