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Residual thenylchlor concentration in soil water and its phytotoxic activity in soil

2007; Wiley; Volume: 7; Issue: 3 Linguagem: Inglês

10.1111/j.1445-6664.2007.00251.x

1445-6664

Hirotatsu Murano, Katsuichiro Kobayashi, Shinsuke Fujihara,

Weed Control and Herbicide Applications

The phytotoxic activity of soil‐applied thenylchlor (2‐chloro‐ N ‐[3‐methoxy‐2‐thenyl]‐2′,6′‐dimethylacetanilide) on the growth of rice seedlings and its behavior in two different types of soil, Ryugasaki soil and Tsukuba soil, after application was investigated with emphasis on the concentration in the soil water. The greatest inhibition of thenylchlor on the growth of rice seedlings was found immediately after application to both the Ryugasaki and Tsukuba soils. The phytotoxic activity decreased with time in both soils. However, the rate of decrease in phytotoxic activity was slower in the Ryugasaki soil than in the Tsukuba soil. The concentration of thenylchlor in soil water, the amount adsorbed on the soil solid, and the amount in the total soil reduced with time after application to both soils. The amount of thenylchlor adsorbed on the soil solid phase was more persistent than that in the soil water in both soils and the concentration in the soil water was higher in the Ryugasaki soil than in the Tsukuba soil at any given time. The residual phytotoxic activity of thenylchlor on the growth of the rice seedlings in the soil was highly correlated with its concentration in the soil water but not with the amount in the total soil. These results suggested that the residual phytotoxic activity of thenylchlor in the soil is determined by its concentration in the soil water after application.