| Abstract: | The phytotoxicities of atrazine, simazine, linuron, lenacil and aziprotryne were increased as the moisture content of the soil increased. Results from studies with 14C-labelled atrazine suggested that these differences could be related to differences in concentrations of herbicide accumulated by the plants. Total uptake of atrazine was directly proportional to water uptake, but a comparison of the amounts taken up with those supplied by mass-flow in the transpiration stream suggested that some exclusion factor was operative. It was concluded that herbicide transport within the soil-plant system was the main factor affecting phytotoxicity under the different soil moisture regimes. The significance of the results to herbicide behaviour under field conditions is discussed. |
