Sorption of frequently used herbicides in different order soils and their ameliorants
Loading...
Date
2020-06
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
CCSHAU,HiSAR
Abstract
Being a non-renewable resource, contamination of water assets through herbicides from
agricultural run-off and wastes from livestock is a growing concern. Such biodegradable waste contains
organic nutrients that are appropriated to be used as raw material in several biological methods.
Sorption of herbicides on adsorbents produced from organic waste is addressed as the most practicable
approach of decontamination. The primary goal of the present research was to identify economical
adsorbent for herbicides elimination from water along with maintaining the soil fertility. Sorption
studies for a range of herbicides (oxyfluorfen, pendimethalin, metribuzin and acifluorfen) were carried
out using the low cost agricultural waste viz. vermicompost and mushroom compost (% OC- 14.56
to15.6%) applied at two different application rates (5 and 25 %, dry weight basis). Compost offered
high sorption, with respect to pure soils, in order: oxyfluorfen > pendimethalin > metribuzin =
acifluorfen. Soil amendment at 25% (w/w) presented 3-102 times increase in sorption. Even 5%
amendment of the soil exhibited a significant increase in sorption by 2 to 33 folds for the four
herbicides comparative to the unamended soil. It is worth mentioning that for highly mobile herbicides
like acifluorfen and metribuzin, sorption increases by 11 to 33 folds (5% w/w). Amendment was quite
effective in low organic carbon soils where sorption of non-mobile herbicide oxyfluorfen also increased
twice with respect to high organic carbon soils. Soil amendment enhanced retention and decreased the
desorption rates of herbicides- especially mobile herbicide metribuzin and anionic herbicide
acifluorfen. Metribuzin and acifluorfen were almost completely 100% desorbed in 1st cycle from
unamended low organic carbon content soils. However, on amendment with 25% (w/w) they retained
on soils and only 77 % (metribuzin) and 26 % (acifluorfen) released in total was observed after 3rd
desorption. Also, amendment at 5% (w/w) exhibit hindrance to desorption of mobile herbicides and
85% and 52% desorption of metribuzin and acifluorfen was observed. Thus, recycling waste through
composting improve defilement of lower soil profiles and water resources concomitantly proper
management of wastes resulting to clean environment.