Factors Influencing Degradation of Pesticides in Soil

Abstract

Degradation and sorption of six acidic pesticides (2,4-D, dicamba, fluroxypyr, fluazifop-P, metsulfuron-methyl, and flupyrsulfuron-methyl) and four basic pesticides (metribuzin, terbutryn, pirimicarb, and fenpropimorph) were determined in nine temperate soils. Results were submitted to statistical analyses against a wide range of soil and pesticide properties to (i) identify any commonalities in factors influencing rate of degradation and (ii) determine whether there was any link between sorption and degradation processes for the compounds and soils studied. There were some marked differences between the soils in their ability to degrade the different pesticides. The parameters selected to explain variations in degradation rates depended on the soil-pesticide combination. The lack of consistent behavior renders a global approach to prediction of degradation unrealistic. The soil organic carbon content generally had a positive influence on degradation. The relationship between pH and degradation rates depended on the dominant mode of degradation for each pesticide. There were positive relationships between sorption and rate of degradation for metsulfuron-methyl, pirimicarb, and all acidic pesticides considered together (all P < 0.001) and for dicamba and all bases considered together (P < 0.05). No relationship between these processes was observed for the remaining seven individual pesticides.

Biodegradation of thifensulfuron-methyl by Ochrobactrum sp. in liquid medium and soil

“…Future studies are required to investigate and optimize these different parameters to increase the degradation efficiency of thifensulfuron-methyl by strain ZWS16. Additionally, Kah et al (2007) reported that sorption processes may affect biodegradation mainly by modifying chemical bioavailability, and suggested that there were positive relationships between sorption and degradation rate for metsulfuronmethyl in soil, whereas such relationships was not found for flupyrsulfuron-methyl. Further research is needed to Fig.…”

Soil heterogeneity at the field scale: a challenge for precision crop protection

“…Amount and quality of soil organic carbon (SOC), texture, pH, and soil moisture govern sorption/desorption processes and thus the mobility of pesticides in soils as reviewed by Wauchope et al (2002). Soil pH can be positively as well as negatively correlated with pesticide degradation as reported by Kah et al (2007) for a number of pesticides and soils. As a consequence, the efficacy of soil-applied herbicides and the leaching risk for pesticides is affected (e.g., Williams et al 2001;Pätzold and Brümmer 2003;Renaud et al 2004;Kah et al 2007).…”

Degradation rates of alachlor, atrazine and bentazone in the profiles of Polish Luvisols

“…2, Table 2), which corroborates the findings of other authors (Blume et al, 2004;Rodríguez-Cruz et al, 2008;Shapir and Mandelbaum, 1997;Yen et al, 1994). The activity of soildwelling microorganisms and their ability to degrade pesticides are positively correlated with organic matter content (Ghafoor et al, 2011b;Kah et al, 2007), which decreases with soil depth. This clearly suggests that microbial degradation was the predominant process in our experiment.…”