Fate of diuron and terbuthylazine in soils amended with two-phase olive oil mill waste

The addition of organic amendments to soil increases soil organic matter content and stimulates soil microbial activity. Thus, processes affecting herbicide fate in the soil should be affected. The objective of this work was to investigate the effect of olive oil production industry organic waste (alperujo) on soil sorption-desorption, degradation, and leaching of diuron [3-(3,4-dichlorophenyl)-1,1-dimethylurea] and terbuthylazine [N2-tert-butyl-6-chloro-N4-ethyl-1,3,5-triazine-2,4-diamine], two herbicides widely used in olive crops. The soils used in this study were a sandy soil and a silty clay soil from two different olive groves. The sandy soil was amended in the laboratory with fresh (uncomposted) alperujo at the rate of 10% w/w, and the silty clay soil was amended in the field with fresh alperujo at the rate of 256 kg per tree during 4 years and in the laboratory with fresh or composted alperujo. Sorption of both herbicides increased in laboratory-amended soils as compared to unamended or field-amended soils, and this process was less reversible in laboratory-amended soils, except for diuron in amended sandy soil. Addition of alperujo to soils increased half-lives of the herbicides in most of the soils. Diuron and terbuthylazine leached through unamended sandy soil, but no herbicide was detected in laboratory-amended soil. Diuron did not leach through amended or unamended silty clay soil, whereas small amounts of terbuthylazine were detected in leachates from unamended soil. Despite their higher sorption capacity, greater amounts of terbuthylazine were found in the leachates from amended silty clay soils. The amounts of dissolved organic matter from alperujo and the degree of humification can affect sorption, degradation, and leaching of these two classes of herbicides in soils. It appears that adding alperujo to soil would not have adverse impacts on the behavior of herbicides in olive production.     

Assessment of three vermicomposts as organic amendments used to enhance diuron sorption in soils with low organic carbon content

Vermicomposts from the wine and distillery industry containing spent grape marc (V1), biosolid vinasse (V2) and alperujo (V3) from the olive‐oil industry were investigated as organic amendments to a sandy and a clay soil with low organic carbon (OC) contents (≤1%). The sorption‐desorption process was studied in batch experiments using diuron as a non‐ionic herbicide model. The effect of soil and vermicompost characteristics, the solution's ionic strength and incubation time of amended soils on the sorption process was studied. The addition of vermicompost changed soil properties and enhanced sorption capacity by two‐ to four‐fold. The K_oc variability showed that exogenous OC composition influenced diuron sorption. Vermicompost V1, which had the largest OC and lignin content, recorded the largest sorption increment. Vermicompost V3, which had the greatest dissolved organic carbon content and a high degree of humification, made the smallest contribution to sorption. Sorption was also dependent on extraneous calcium in the solution. The incubation of amended soils reduced diuron sorption efficiency except with V3. Pyrolysis‐gas chromatography (Py‐GC) analysis was a useful tool to characterize the vermicomposts and to understand the variation of diuron sorption constants after vermicompost incubation. This research encourages the use of vermicompost from agro‐industrial wastes as a sustainable means to minimize the side effects of neutral herbicides.     

Comparative sorption and leaching study of the herbicides fluometuron and 4-chloro-2-methylphenoxyacetic acid (MCPA) in a soil amended with biochars and other sorbents

Biochar, the solid residual remaining after the thermochemical transformation of biomass for carbon sequestration, has been proposed to be used as a soil amendment, because of its agronomic benefits. The effect of amending soil with six biochars made from different feedstocks on the sorption and leaching of fluometuron and 4-chloro-2-methylphenoxyacetic acid (MCPA) was compared to the effect of other sorbents: an activated carbon, a Ca-rich Arizona montmorillonite modified with hexadecyltrimethylammonium organic cation (SA-HDTMA), and an agricultural organic residue from olive oil production (OOW). Soil was amended at 2% (w/w), and studies were performed following a batch equilibration procedure. Sorption of both herbicides increased in all amended soils, but decreased in soil amended with a biochar produced from macadamia nut shells made with fast pyrolysis. Lower leaching of the herbicides was observed in the soils amended with the biochars with higher surface areas BC5 and BC6 and the organoclay (OCl). Despite the increase in herbicide sorption in soils amended with two hardwood biochars (BC1 and BC3) and OOW, leaching of fluometuron and MCPA was enhanced with the addition of these amendments as compared to the unamended soil. The increased leaching is due to some amendments' soluble organic compounds, which compete or associate with herbicide molecules, enhancing their soil mobility. Thus, the results indicate that not all biochar amendments will increase sorption and decrease leaching of fluometuron and MCPA. Furthermore, the amount and composition of the organic carbon (OC) content of the amendment, especially the soluble part (DOC), can play an important role in the sorption and leaching of these herbicides.     

Availability of triazine herbicides in aged soils amended with olive oil mill waste

Amendments are frequently added to agricultural soils to increase organic matter content. In this study, we examined the influence of alperujo, an olive oil mill waste, on the availability of two triazine herbicides, terbuthylazine and atrazine, in two different sandy soils, one from Sevilla, Spain, and the other from Minnesota. The effect of aging on herbicide sorption and bioavailability was also studied. Soils were amended with alperujo at a rate of 3-5% (w:w) in laboratory studies. Apparent sorption coefficients for the triazine herbicides were calculated as the ratio of the concentrations of each herbicide sequentially extracted with water, followed by aqueous methanol, at each sampling time. These data showed greater sorption of terbuthylazine and atrazine in amended soils as compared to nonamended soils, and an increase in the amount of herbicide sorbed with increasing aging time in nonamended soils. The triazine-mineralizing bacterium Pseudomonas sp. strain ADP was used to characterize triazine bioavailability. Less mineralization of the herbicides by Pseudomonas sp. strain ADP was observed in soils amended with alperujo, as compared to the unamended soils, and, despite the increase in sorption with aging in unamended soils, herbicide mineralization also increased in this case. This has been attributed to Pseudomonas sp. strain ADP first using alperujo as a more readily available source of N as compared to the parent triazines. In summary, addition of alperujo to the soils studied was shown to increase triazine herbicides sorption and hence to reduce its availability and potential to leach.     

Estimating soil resilience to a toxic organic waste by measuring enzyme activities

The ability of a degraded soil to respond to successive additions of a toxic organic waste (olive-mill solid waste) and its vermicompost was studied in a controlled incubation experiment for 32 weeks. Hydrolytic enzyme activities (phosphatase, β-glucosidase), oxidoreductase activities (dehydrogenase, o-diphenol oxidase) and indole acetic acid production, were used as measures of soil perturbation. No microbial activity, indicated by the total lack of dehydrogenase activity, was detected when the olive-mill solid waste was added to the soil. However, after 16 weeks, the activity returned to the original soil levels (1.35 μg INTF g⁻¹ h⁻¹). The addition of vermicomposted olive-mill solid waste increased the original soil dehydrogenase activity by five-fold, indicating a loss of toxicity of the waste during the vermicomposting process; the activity remained high throughout the experiment. At week 21, a second addition of olive solid waste, was made to both olive waste and vermicompost-amended soils, when the soil originally amended with olive waste had reached the activity measured in soil amended with vermicompost. Dehydrogenase activity recovered immediately, reaching levels up to seven-fold higher than the background levels of the soil. The ability of soil to respond to a toxic waste clearly differed after a period of exposure to the waste. The faster response was probably related to the increased pool of stabilized organic matter present in soil, arising from the stabilization of added olive waste in the soil or through the amended vermicompost. The amplitude (period of recovery to the initial state after disturbance) and the elasticity (speed of recovery) of the soil could also be monitored by o-diphenol oxidase and β-glucosidase activities. However, indole-3-acetic acid production proved to be a useful measure of perturbation only following the second addition of the olive waste.     

Effects of solid olive-mill waste addition to soil on sorption, degradation and leaching of the herbicide simazine

Abstract. A laboratory study was conducted to investigate the effects of adding an intermediary byproduct of olive oil extraction ( alperujo or solid olive-mill waste, SOMW) on the sorption, degradation and leaching of the herbicide simazine in a sandy loam soil. The effect of SOMW addition on soil porosity was also assessed. The soil was amended in the laboratory with SOMW at two different rates (5% and 10% w/w). Simazine sorption isotherms showed a great increase in herbicide sorption after SOMW addition to soil; sorption increased with the amount of SOMW added. Incubation studies showed extended persistence by reduced biodegradation of simazine in the soil amended with SOMW compared with the unamended soil. Although the addition of SOMW to soil increased the total porosity, breakthrough curves of simazine in handpacked soil columns showed that SOMW addition retarded the vertical movement of the herbicide through the soil and reduced the total amount of herbicide leached. It appeared that the longer residence time of simazine in the amended soil columns (>20 days) compared with that in the unamended soil column (<20 days) allowed enhanced degradation and/or irreversible sorption under column leaching conditions. The results revealed important changes in herbicide behaviour upon SOMW addition, confirming the need to assess these changes in order to optimize the combined use of organic wastes and soil-applied pesticides.     

Organic amendments from olive cake as a strategy to modify the degradation of sulfonylurea herbicides in soil

Amending soil with products rich in organic matter, such as raw olive cake or alperujo and its compost and vermicompost, could be a simple bioremediation strategy for soil pollutants such as pesticides. To investigate this hypothesis in relation to sulfonylurea herbicides, these amendments were applied to a Mediterranean agricultural soil at rates 4 times higher than agronomical dosage to stimulate biodegradation of chlorsulfuron, prosulfuron, and bensulfuron, added in a mixture to the soils. Degradation studies were conducted in microbially active and sterile soils to check the importance of biological and chemical degradation of sulfonylurea herbicides in nonamended and amended soil. The addition of alperujo stimulated soil microbial activity, as determined by dehydrogenase activity measurements, but it did not enhance the degradation of the sulfonylurea herbicides. In contrast, compost and vermicompost slightly favored the biological degradation of bensulfuron during the first week of incubation. Chlorsulfuron and prosulfuron were mainly degraded by chemical pathways in all substrates, which is probably due to a competitive or inhibitory phenomenon observed between chlorsulfuron and bensulfuron. The first-order kinetic equation satisfactorily explained the experimental data for chlorsulfuron and prosulfuron; however, a biphasic model, such as that proposed by Hoerl, better predicted the results obtained for bensulfuron.     

Effect of Olive‐Derived Organic Amendments on Lead,Zinc, and Biochemical Parameters of an Artificially Contaminated Soil

Abstract

An incubation experiment was conducted to ascertain the effects of three olive‐derived organic amendments (fresh, compost, and vermicompost olive cake) on the soluble and diethylenetriamine pentaacetic acid (DTPA)–extractable lead (Pb) and zinc (Zn) and on different enzymatic activities in an artificially contaminated calcareous soil. Application of the compost and vermicompost, which increased amounts of humic acids in soil, initially stimulated dehydrogenase, ß‐glucosidase, and urease activities, which tended to decline afterward. In contrast, dehydrogenase and ß‐glucosidase activities were lower after application of the fresh olive cake. Amounts of soluble Pb and Zn increased when fresh olive cake was added to the soil, due to the high content of water‐soluble carbon in this amendment. On the contrary, application of the compost and vermicompost decreased the concentration of soluble Zn and did not change the soluble Pb levels in the soil. The DTPA‐Pb and DTPA‐Zn were scarcely affected by the application of the three olive‐derived amendments.     

Dissolved organic carbon interactions with sorption and leaching of diuron in organic-amended soils

Diuron ( N '-[3,4-dichlorophenyl]- N,N -dimethylurea) is one of the most frequently used herbicides in olive groves in Spain and other Mediterranean countries. The main objective of this work was to investigate the effect of the dissolved organic carbon (DOC) from a commercial humic amendment, derived by composting the liquid waste of the olive-mill process (LF), and a solid residue from the olive oil production industry (AL) on the sorption and leaching behaviour of diuron in soil. For this purpose, a clay and a sandy soil were selected. Soil sorption coefficients of diuron increased with LF (32%) and AL (76%) amendment in the sandy soil, whereas sorption decreased in the clay soil upon amendment, especially in the case of the liquid LF (52%). The DOC from LF and AL is composed of very poorly humified molecules, which are strongly sorbed onto the clay soil and thus compete with diuron for the same sorption sites. Dialysis experiments revealed that diuron forms stable complexes with DOC from LF and AL. Leaching of diuron in columns of the sandy soil treated with the organic amendments caused earlier breakthrough and maximum concentration peaks at fewer pore volumes when compared with leaching with 0.01 m CaCl₂. Competition between diuron and DOC molecules for sorption sites and diuron–DOC interactions can both account for the enhanced leaching of diuron.     

Retention of copper by a calcareous soil and its textural fractions: influence of amendment with two agroindustrial residues

Metal availability in soils is strongly related with sorption processes and the possible association of the metal ions with a particular particle-size fraction. Therefore, studies of metal retention by a soil will be aided if retention by different size fractions is also studied. Sorption of copper on a calcareous soil and its textural fractions was studied in batch assays. The soil was amended over 3 years with two agroindustrial residues, a composted olive mill sludge and vinasse. Sorption of Cu on the calcareous soil was very large (110 mmol kg⁻¹) and was enhanced by both amendments. Metal retention by the clay fraction of the unamended soil was less than that of the whole soil, but increased dramatically after amendment with olive mill sludge. This was caused by the larger calcite content in this fraction as well as the increase in organic matter content. The amount of Cu sorbed was very large in the silt fraction, again because of the carbonate content of this fraction (300–460 g kg⁻¹). Copper sorption decreased dramatically after removal of carbonate. Copper retention tended to be enhanced by organic amendments. This was particularly evident in the silt fraction, as a consequence of the organic matter accumulation in this fraction.
Copper sorption on the calcareous soil and its silt fractions (unamended and amended) was irreversible. By contrast, desorption was measurable from all the carbonate-free samples (both whole soil and textural fractions), although in all cases a large hysteresis was observed. We conclude that carbonate was the main component responsible for the lack of reversibility.     

Influence of two-phase olive mill waste application to soil on terbuthylazine behaviour and persistence under controlled and field conditions

Purpose  

Terbuthylazine is one of the most common herbicides used to control weeds in olive groves. Application of two-phase olive mill waste (OW) to soils may play a fundamental role in the management of leaching losses of pesticides, especially in Mediterranean areas where soils are characterized by low organic matter levels. We evaluated the impact of OW amendments on the sorption–desorption, degradation, leaching, and persistence of the herbicide terbuthylazine in a representative olive grove soil from Portugal.     

Sorption of s-Triazine Herbicides in Organic Matter Amended Soils: Fresh and Incubated Systems

Fresh amendment of soil with sewage sludge and composted sewage sludge resulted in increased sorption of three s-triazine herbicides: atrazine, ametryn and terbuthylazine. The extent of increased sorption (as evaluated by sorption coefficients K_d or K_f) was a function of soil type, such that sorption in amended organic carbon-poor soil (0.4% OC) was more enhanced than in amended organic carbon-rich soil (1.55% OC). Despite significant differences between the organic amendments in terms of humic and fulvic acid content, humin content, soluble organic matter content, total organic matter content, and H/C and O/C atomic ratios, organic matter composition had no discernible effect on either sorption distribution coefficients or on isotherm linearity in amended soils. Soils amended with composted sludge had the same sorption potential as did soils amended with the analogous uncomposted sludge. After incubating soil-sludge mixtures for a year at room temperature, organic matter content decreased to original pre-amendment levels. Sorption coefficients for the three compounds similarly decreased to initial pre-amendment values. Organic carbon normalized sorption coefficients (K_oc) were essentially identical in the soils, amended soils, and incubated amended soils, indicating that sludge and compost derived organic matter does not have a significantly different sorption capacity as compared with the original soils, despite compositional differences.     

A glass house trial to investigate the impact of water treatment sludge and green waste compost to enhance the revegetation of contaminated sites

This study investigated the use of waste amendments (green waste compost (GWC) and water treatment sludge (WTS) cake) in improving the nutrient and revegetation status of contaminated soil obtained from a former industrial site that has heavy metal and hydrocarbon contamination. The waste amendments were mixed with the contaminated soil at application rates equivalent to 90 and 180 t ha^?1 (wet weight) and placed in plastic pots. The unamended soil serves as the control. Reed canary grass and white mustard were allowed to grow on the amended and unamended contaminated soil in the glass house. After a 30- day growth period, soil nutrient status was observed and was found to be higher in the amended contaminated soil than the control. In the amended soil, organic matter, total nitrogen, total potassium and soil nitrate were highest in contaminated soil amended with GWC at 180 t ha^?1 and lowest in contaminated soil amended with WTS cake at 90 t ha^?1. Above-ground dry mass of reed canary grass and white mustard grown on amended contaminated soil increased by 120–222% and 130–337%, respectively, as compared to the control, showing that improved fertility of contaminated soils thereafter, enhanced revegetation.     

Effects of Wood Amendments on the Degradation of Terbuthylazine and on Soil Microbial Community Activity in a Clay Loam Soil

The herbicide terbuthylazine is widely used within the EU; however, its frequent detection in surface and groundwater, together with its intrinsic toxicological properties, may pose a risk both for human and environmental health. Organic amendments have recently been proposed as a possible herbicide sorbent in soil, in order to limit herbicide movement from soil to water. The environmental fate of terbuthylazine depends not only in its mobility but also in its persistence. The latter is directly dependent on microbial degradation. For this reason, the effects of pine and oak residues on terbuthylazine soil microbial community functioning and on the potential of this community for terbuthylazine degradation were studied. For this purpose, degradation kinetics, soil dehydrogenase activity and the number of live bacteria were assessed in a clay loam soil treated with terbuthylazine and either amended with pine or oak wood or unamended (sterilised and non-sterilised). At day 65, 85?% of the herbicide applied still persisted in the sterile soil, 73?% in the pine-amended one and 63?% in the oak-amended and unamended ones. Pine residues increased the sorption of terbuthylazine to soil and hampered microbial degradation owing to its high terbuthylazine sorption capacity and a decrease in the bioavailability of the herbicide. On the contrary, in the presence of oak residues, the herbicide sorption did not increase significantly. The overall results confirm the active role of the soil microbial community in terbuthylazine degradation in amended and unamended soils and in a liquid enrichment culture performed using an aliquot of the same soil as the inoculum. In this clay loam soil, in the absence of amendments, the herbicide was found to be quite persistent (t _1/2?>?95?days), while in the enrichment culture, the same natural soil bacterial community was able to halve terbuthylazine in 24?days. The high terbuthylazine persistence in this soil was presumably ascribable to its texture and in particular to the mineralogy of the clay fraction.     

酰胺类除草剂在土壤上吸附的位置能量分布分析

根据异丙甲草胺、乙草胺、丙草胺和丁草胺在六种土壤上的等温吸附结果 ,计算了它们在六种土壤上的位置能量分布和有机质标化的平均分配常数。结果表明 :四种除草剂在六种土壤上的吸附等温线为Freundlich型 ;低浓度范围内 ,农药在土壤上的吸附首先发生在土壤表面的高能吸附位置上 ;土壤表面位置能量分布的具体情况与被吸附农药性质有关 ;土壤上的吸附位置数或吸附容量主要与土壤有机质含量有关 ,粘土对吸附也有一定的贡献 ;疏水键合机理在四种酰胺类除草剂吸附过程中起着重要的作用     

Effects of Organic Matter-Rich Amendments on Selenium Mobility in Soils

Soil organic matter (SOM) plays an important role in the Se dynamics in soil. The potential effects of vermicompost and digestate as important sources of SOM on selenium (Se) mobility were assessed in this study. Three soils differing in their physicochemical parameters, fluvisol, chernozem, and luvisol, were chosen, and three types of vermicomposts based on various bio-waste materials as digestate (vermicompost 1), kitchen waste with woodchips (vermicompost 2), and garden bio-waste (vermicompost 3) were used due to their high organic matter content. Additionally, digestate samples alone were applied. To evaluate the potential effect of vermicompost application on sorption characteristics of soils, batch sorption experiments were performed. The results showed a predominant effect on Se species in the soils, where selenite sorbed more intensively compared to selenate, regardless of the soil and ameliorative material applied. In the control, the soil sorption ability of selenite tended to decrease in the order:fluvisol > luvisol > chernozem. However, these differences were not significant. Moreover, the effects of the ameliorative materials depended on both soil and amendment used. In fluvisol, all the amendment applications resulted in a decrease in distribution coefficient (K_d values) of Se, whereas in chernozem, this effect was observed only for the digestate-based vermicompost 1. Increasing K_d levels were reported in luvisol treated with digestate; the application of garden bio-waste-based vermicompost 3 tended to decrease the K_d values. Further studies are required on long-term effects of these amendments on Se mobility in soils and the role of individual organic matter fractions in this context.     

The effect of earthworms on carbon storage and soil organic matter composition in tropical soil amended with compost and vermicompost

The use of organic matter (OM) amendments is widespread in tropical countries and may be beneficial for soil carbon storage. Interactions between earthworms and OM amendments in tropical soils are largely unknown. The aim of this study was to investigate the effect of bioturbation on the quantity and chemical composition of OM in soil amended with compost and vermicompost. Our approach included comparison of soil samples amended with compost, vermicompost or chemical fertilizers in the presence or absence of earthworms during a one-year greenhouse experiment. The soils were submitted to a regular cultivation cycle. After one year, we analysed bulk samples for soil OM elemental composition and characterised its lignin and non-cellulosic carbohydrate components.Our results showed a decrease of the carbon and nitrogen content in soil amended with chemical fertilizers. Vermicompost amendment led to unchanged OC content, whereas the compost amendment increased the soils OC content compared to initial soil. The addition of earthworms reduced OC and N content in soils with organic amendments. This is in contrast to soil amended with mineral fertilizer only, where the presence of earthworms did not have any effect. Bioturbation influenced the lignin signature of the soils, and to a lesser extent the non-cellulosic carbohydrate signature. In conclusion, compost amendment combined with bioturbation influenced the quality and quantity of SOM and as result carbon storage and its biogeochemical cycling in tropical soils. Implications for soil fertility remain to be elucidated.     

Suitability of Wastes from Olive-Oil Industry for Initial Reclamation of a Pb/Zn Mine Tailing

An incubation experiment was conducted to evaluate the ameliorating role of two organic amendments—olive-mill solid wastes and compost from olive-mill solid wastes- in the ecological reclamation of a lead/Zn-mine tailing collected in southern Spain. Four enzymatic activities (dehydrogenase, β-glucosidase, urease and phosphatase) and soluble and AB-DTPA extractable Pb and Zn and were periodically determined. High concentrations of Pb (5394 mg kg^?1) and Zn (9607 mg kg^?1), mainly in insoluble forms, were recorded in the lead/zinc-mine tailing, as well as very low biochemical activity. Application of the compost from olive-mill solid waste stimulated microbial activity and the biogeochemical cycles into the mine tailing because of the initially increased dehydrogenase, β-glucosidase and urease activities, which tended to decline or remained constant during the incubation period. By contrast, these enzyme activities were scarcely affected by the incorporation of the olive-mill solid wastes because this olive-organic amendment contains extractable polyphenols (36 g kg^?1), which inhibit these enzyme activities. Phosphatase activity was enhanced by the application of both olive-organic amendments, especially when the olive-mill solid waste was added to the mine tailing. Amounts of soluble and AB-DTPA-extractable Pb and Zn in the mine tailing were increased by the application of the olive-mill solid waste, and to a lesser degree, by the compost from this olive waste. This fact could restrict the use of these olive-organic amendements as useful materials in reclamation of lead/zinc-mine tailings. Nevertheless, the increases of available lead and zinc would represent an advantage where Pb/Zn-mine tailings are reclaimed by phytoextraction, effectively reducing the metal pollution in these mining wastes.     

复垦沉积池土壤中镍、铅、锌的吸附

The wastes used to amend soils sometimes have high concentrations of metals such as nickel (Ni), lead (Pb) and zinc (Zn). To determine the capacity of soils to retain these metals, the sorption capacities of different mine soils with and without reclamation treatments (tree vegetation and waste amendment) for Ni, Pb and Zn in individual and competitive situations were evaluated using the batch sorption technique. The untreated settling pond soil had low capacity for Ni, Pb and Zn retention. The site amended with wastes (sewage sludges and paper mill residues) increased the sorption capacity most, probably because of the higher concentrations of soil components with high retention capacity such as carbon and clay fraction. No significant competition was observed between metals in the competitive sorption experiment, indicating that the maximum of sorption was not achieved by adding 0.5 mmol L^-1 of metal. We can conclude that, despite the possible additions of Ni, Pb and Zn from wastes to degraded soils, sewage sludges and paper mill residues have a high sorption capacity that would prevent the metals from being in a mobile form.     

Influence of organic amendment on the adsorption and leaching of ethametsulfuron-methyl in acidic soils in China

The sorption and leaching of ethametsulfuron-methyl by an acidic soil, after organic amendment with humic acid (HA) and a commercial peat, were studied in batch and soil column experiments. Adsorption capacity (K_f) values, obtained by fitting the experimental data to the Freundlich equation, ranged from 4.39 for the original soil containing 1.02% OC to 10.56 for the organic amended soils containing 2.61% OC. The increase in herbicide adsorption by organic amendment addition to soil was attributed to the high adsorptive capacity of the insoluble organic matter added to the soil. Evidence provided by FT-IR analysis suggested multifunctional hydrogen bonds were involved in the adsorption of ethametsulfuron-methyl on organic matter. The distribution of ethametsulfuron-methyl along the soil profile, obtained from soil column experiments, indicated that the amount of ethametsulfuron-methyl retained ranged from 68.4% for the column filled with the original soil to 92.4% for that filled with the organic amended soil. Amounts of ethametsulfuron-methyl recovered in the leachates, which ranged from 7.7% (organic amended soil) to 23.7% (unamended soil) of that applied, depended upon the loading rate and the source of organic amendment. Organic amendments significantly reduced the leaching of ethametsulfuron-methyl, and humic acid showed the higher potential than peat. This research suggests that organic amendment may be an effective management practice for controlling pesticide leaching.