Publication Date:
1990-08-01
Description:
The persistence of the herbicidal ester (14C)thiameturon was studied at different temperature and moisture conditions in three Saskatchewan soils. In all soils at 20 °C and 85% field capacity, the (14C)ester underwent rapid hydrolysis to (14C)thiameturon acid. The hydrolysis was over 85% complete in 1 week, and more than 95% complete after 2 wk. The soil degradation of (14C)thiameturon acid was considerably slower than that of the parent ester. Transformation of (14C)thiameturon to acid in all soils at 85% field capacity was temperature dependent, being slowest at 10 °C, and fastest at 30 °C. Conversion to the acid was also moisture dependent. There was no hydrolysis in air-dry soils after 10 wk. At 50% field capacity 22% of the ester remained after 1 wk, and at field capacity less than 2% of the applied ester was recoverable after 1 wk. Soils treated with thiameturon acid at rates up to 500 μg g−1 exhibited no phytotoxicity to canola, lentil, or sugarbeet seedlings. Key words: Herbicide, thiameturon, persistence, phytotoxicity
Print ISSN:
0008-4271
Electronic ISSN:
1918-1841
Topics:
Geosciences
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Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
