Impact of spatial distribution of exogenous organic matter on C mineralization and isoproturon fate in soil

Effect of Multiple Stresses, Organic Amendment and Compaction, on the Fate and Impact of Isoproturon in Soil

“…The formation of non-extractable residues leads to a decrease in the toxicity and bioavailability of pesticides in the short term, but it could lead to further environmental contamination in the long term [39]. At the end of the incubation, the mineralisation of isoproturon ranged from 19.0% to 22.4% (in per cent of initial 14 C) which was consistent with previous observations [5,14,21,27]. There was no significant difference among the various soil treatments (control unamended and compost amended, compacted and not compacted) (p > 0.05) (Figure 1).…”

“…There was no significant difference among the various soil treatments (control unamended and compost amended, compacted and not compacted) (p > 0.05) (Figure 1). From 0 to 49 days, a decrease in the extractable 14 C was observed with a concomitant increase in the mineralisation and in the amounts of non-extractable residues (Figure 2). The amounts of extractable 14 C were very high at Days 0 and 7 (more than 90% and 45% of recovered 14 C, respectively), but low at Day 49 (<15%).…”

“…From 0 to 49 days, a decrease in the extractable 14 C was observed with a concomitant increase in the mineralisation and in the amounts of non-extractable residues (Figure 2). The amounts of extractable 14 C were very high at Days 0 and 7 (more than 90% and 45% of recovered 14 C, respectively), but low at Day 49 (<15%). At Day 0, most of the 14 C was extracted with CaCl2 while, at Day 49, it was mainly extracted by methanol ( Figure 2).…”

“…At Day 0, most of the 14 C was extracted with CaCl 2 while, at Day 49, it was mainly extracted by methanol ( Figure 2). The CaCl 2 -extractable 14 C provides an estimate of the availability of pesticide residues, which could be directly related to the risk of pesticide leaching and consequently to the risk of groundwater contamination by the herbicide and/or its metabolites. Therefore, the results indicate that these risks are very high in the first days following the application of isoproturon as an aqueous solution ( Figure 2).…”

“…Organic amendment addition can change the physical (soil bulk density, aggregate stability, moisture retention and porosity), chemical (cationic exchange capacity, electric conductivity and addition of contaminants) and biological (stimulation of indigenous microflora and introduction of exogenous microorganisms) properties of soils. These changes can impact the fate of pesticides: in general, the mobility of pesticides decreases and their persistence increases in amended soils compared to unamended ones [4][5][6][7][8][9][10][11][12][13][14].…”