Rainfast Characteristics of HWS

For the purpose of determining the influence of environmental factors and rainfall, herbicidal activity of 30 % BTWS EC, was determined at different times of treatment under a simulant rainy condition. 41 % MCPA EC was included as a positive control. Common amaranth Amaranthus retroflexus) was used as the tested plant. 

Herbicides Rate (g ai/ha) Rain time and conesponding inhibitory activity (%)  

As seen from Table 8.29, the effect of HWS would decrease about 20 % if the plants were scoured by rainwater in 4 h, about 10 % in 8 h. Under the same treatment, MCPA would decrease more than 40 % in 8 h. HWS had stronger stability in rainfall than MCPA. This is due to the rapid absorption and good osmosis of HWS. Data showed that the herbicidal effect of HWS would be fully realized if the treatment is completed 8 h before it rains. 

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