Effects of chlorothalonil and carbendazim on nitrificationand denitrification in soils
LANG Man , CAI Zucong
DOI:
Received May 15, 2008,Revised July 28, 2008, Accepted , Available online
Volume 21,2009,Pages 458-467
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The effects of chlorothalonil and carbendazim on nitrification and denitrification in six soils in upland and rice paddy environments
were investigated. Laboratory aerobic (60% water holding capacity) and anaerobic (flooded) conditions were studied at 25°C and
fungicide addition rates of 5.5 mg/kg A. I. (field rate, FR), 20 times (20FR) and 40 times (40FR) field rate, respectively. The results
indicated that chlorothalonil at the field rate had a slight inhibitory e ect on one soil only, and that soil did not nitrify much in the first
place. But chlorothalonil at higher rates inhibited nitrification significantly in all soils. For soils JXP and JXU with a pH of less than 5.0,
chlorothalonil almost completely stopped their nitrification at 20FR and 40FR during the whole 14 d incubation period. For soils HNP
and HNU with a pH of greater than 8.0, chlorothalonil also significantly inhibit nitrification at 20FR and 40FR (p < 0.05). However,
NH4
+ that was added to the soil was also almost completely nitrified by the end of the incubation period in these two soils. The e ects
of chlorothalonil at 20FR and 40FR on the nitrification of JSP and JSU soils, with a pH of 5.4 and 7.2, respectively, were intermediate
between the other soil types. Chlorothalonil had no e ect on denitrification at the field rate and had little e ect at the higher rates of
application in some soils. Carbendazim had essentially no e ect on nitrification and denitrification in soils assessed.
