Impact of clodinafop herbicide on soil microflora and their biochemical activities in wheat field soil
Loading...
Date
2006
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
CCSHAU
Abstract
In the present investigation, effect of long term use of clodinafop herbicide
(used as permanent and rotational herbicide) on soil microbial populations and
their activities in wheat field soil was studied. Soil samples collected before the
application of herbicide were analyzed for soil chemical properties. Soil was of
clay loam type. Soil pH ranged from 8.4-8.6 and EC ranged from 0.23-0.44 dSm-1.
Organic carbon and total N were more in green manuring (GM) treatments than
without green manuring (WGM) treatments. Total bacterial population was more
in GM treatments than WGM treatments. At 15 days after the treatment (DAT) of
herbicide, bacterial population was significantly less in rotational herbicide treated
plot than weedy control under both GM and WGM conditions. At 30 & 60 DAT,
bacterial count was more in permanent herbicide treated plots than rotational
herbicide treated plots and weedy and weed free controls. Free living diazotrophs count was also more in GM treatments than WGM treatments. At 30 DAT, count
was more in herbicide treated plots than weedy and weed free controls of GM
condition while in WGM condition, there was not much difference in the
population of different treatments. Ammonium oxidizer population increased after
the application of herbicide in all the treatments upto 30 DAT. In GM condition,
population was less in permanent herbicide treated plot at 15 DAT and in both
(permanent and rotational) herbicide treated plots at 30 DAT as compared to
weedy and weed free controls while in WGM condition, population was less only
in rotational herbicide treated plot than weedy control at 15 DAT. Nitrite oxidizer
population decreased after the application of herbicide in all the treatments. At 15
DAT, population was less in herbicide treated plots than weedy control in GM
condition while in WGM condition, population was less only in rotational
herbicide treated plot than weedy control. At 30 DAT, population increased and
was significantly higher in permanent herbicide treated plots than weedy and weed
free controls.
Basal respiration, as indicated by carbon dioxide evolved, was slightly more
in herbicide treated plots than weedy and weed free controls at 15 DAT and only in
rotational herbicide treated plot at 30 DAT under both GM and WGM conditions.
Later on, with the progress of time after application of herbicide, not much
differences were observed in the basal respiration of different treatments under
both GM and WGM conditions. Dehydrogenase activity was slightly higher in herbicide treated plots than weedy control of GM condition at 30 & 60 DAT while
in WGM condition, activity was significantly less in herbicide treated plots than
weedy control. Although herbicide treatments of GM condition had higher alkaline
phosphatase activity than herbicide treatments of WGM condition but activity was
less in herbicide treatments than weedy control at 15 & 30 DAT under GM
condition while in WGM condition, enzyme activity in herbicide treated plots was
not less than weedy control.