Abstract
Degradation of diphenyl ether herbicides was studied in six soils under flooded conditions. The half-life periods largely varied depending on soil: 9 to 173 days for chlornitrofen (CNP), 3 to 87 days for nitrofen (NIP) and 8 to 64 days for chlomethoxynil, but the patterns and rates of the degradation were similar in a soil. No significant correlations were found between the degradation rates of the chemical and the physicochemical properties of the soils, while significant negative correlations were observed between the half-life periods of the chemicals and the soil redox potentials. The degradation of chlornitrofen was largely affected by the preincubation period of soil and the amendment of organic substances to soil. The herbicides were rapidly degraded at a lower redox potential of soil.
