Joint effects of acetochlor and urea on germinating characteristics of crop seeds

In order to evaluate ecological risk of agrochemicals in common use, joint toxic effects of acetochlor and urea on germinating characteristics of Chinese cabbage (Brassica Pekinensis Rupr) seeds were investigated using the water-culture method and the soil-culture method. The results indicated that excessive application of acetochlor and urea, when the concentrations were higher than 31.3 mg x kg(-1) for acetochlor and 500 mg x kg(-1) for urea, had strong inhibitory effects on the rate of seed germination, root elongation and hypocotyl length of Chinese cabbage. The inhibitory rate of the germinating characteristics of Chinese cabbage seeds was significantly increased with an increase in the concentration of acetochlor or urea. The two agrochemicals in water had a stronger toxicity than these in the soil at the same concentration. Among the three indexes, hypocotyl length was the most sensitive to the toxicity of acetochlor and urea.