Effect of olive-mill waste addition to soil on sorption, persistence, and mobility of herbicides used in Mediterranean olive groves

Abstract

Laboratory and field experiments were conducted to evaluate the effect of olive-mill waste (OMW) addition to a Mediterranean olive grove soil on sorption, persistence, and mobility of two herbicides which are simultaneously applied for weed control in olive groves: terbuthylazine (TA) and fluometuron (FM). Laboratory batch sorption experiments showed that OMW addition to the soil at rates of 5 and 10% (w/w) greatly enhanced the sorption of both herbicides, thus suggesting that amendment with OMW could be useful to enhance the retention and reduce the mobility of FM and TA in the soil. Incubation experiments showed that OMW increased the persistence of FM and had little effect on the long persistence of TA in the soil studied. A demonstration field experiment was also conducted in field plots with a slope of about 5%, either unamended or amended with OMW at a rate of 10 kg m⁻², and then treated with a commercial formulation containing a mixture of TA and FM. Extraction of field soil samples, taken from different soil depths (0-5, 5-10, 10-20, and 20-30 cm) at different times after herbicide application, showed that both TA and FM moved deeper in unamended soil than in OMW-amended soil, and that OMW addition affected the persistence of FM in the toplayer, increasing its half-life from 24 to 58 days, while having little effect on the persistence of TA. Thus, data obtained under real field conditions were consistent with those obtained under controlled laboratory conditions. Preliminary herbicide runoff data indicated that the total herbicide runoff losses were also reduced upon OMW addition. Addition of OMW could be beneficial in reducing the mobility of TA and FM in olive grove soils, and also in increasing the persistence of FM in soils where this herbicide could be rapidly degraded.

Evaluation of an organo-layered double hydroxide and two organic residues as amendments to immobilize metalaxyl enantiomers in soils: A comparative study

“…Sorption of metalaxyl by both soils was found to be non-enantioselective, that is, the two enantiomers were sorbed to the same extent, and the addition of the amendments did not affect the non-enantioselective character of metalaxyl sorption in the soils tested. These results agree with previous sorption studies of rac-metalaxyl on soils and soil components G amiz et al, 2013;Sukul et al, 2013).…”

“…3, Table 2). This result has previously been observed by G amiz et al (2013) in a soil very similar to our soil 2 amended with ALP, and was attributed to changes in microbial populations after amendment, the presence of a new C or energy source for microorganisms, and/or some toxic effects of ALP on metalaxyl degraders, as suggested for other pesticides after amending soil with fresh olive-mill wastes (Fernandes et al, 2006;G amiz et al, 2012;Peña et al, 2015). In soil 2 amended with ALP, both the value of EF at the end of the incubation period (EF ¼ 0.60) and the ES factor (ES ¼ 0.27) confirmed that enantioselectivity in metalaxyl dissipation was less pronounced than in unamended soil (EF ¼ 0.83, ES ¼ 0.74), because the degradation patterns of the two enantiomers became more similar.…”

Effect of synthetic clay and biochar addition on dissipation and enantioselectivity of tebuconazole and metalaxyl in an agricultural soil: Laboratory and field experiments

“…This low density was attributed to some soil disturbance upon sampling, as the 0-5 cm soil section in the sampling spade was visually less compacted than deeper soil sections. The slightly higher initial fungicide concentrations observed for clay-and BCamended soil compared to unamended soil (significant for metalaxyl) could also reflect slight differences in soil density after amendment, as previously suggested for organically-amended field soils (Gámiz et al, 2012). On the other hand, since soil concentration data were simultaneously influenced by fungicide degradation and transport losses, to evaluate leaching we calculated the fraction of residues at different soil depths relative to the total amount extracted from the 0-20 cm soil profile.…”

Different Effects of a By‐product From Olive Oil Extraction on S‐Metolachlor and Bentazone Soil Fate

“…The use of soil organic amendments [8][9][10][11][12][13][14] can reduce drift of some pesticides from one compartment to other in agricultural soils by increasing its sorption, previously recognized as one of the main processes determining the behaviour of pesticides in soils [15].…”