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This study evaluated the changes in microbial activity in the course of time following the joint application of the herbicides S-metolachlor, foramsulfuron, and thiencarbazone-methyl to two soils (S1 and S2) under conventional tillage (CT) and non-tillage (NT) management in field conditions. The biochemical parameters of soil respiration (RES), dehydrogenase activity (DHA), microbial biomass (BIO), and the phospholipid fatty acid (PLFA) profile were determined at 1, 34, and 153 days during herbicide dissipation. In the absence of herbicides, all microbial activity was higher under NT than CT conditions, with higher or similar mean values for S1 compared to S2. A continuous decrease was detected for RES, while DHA and BIO recovered over time. In the presence of herbicides, a greater decrease in all microbial activity was detected, although the changes followed a similar trend to the one recorded without herbicides. In general, a greater decrease was observed in S1 than in S2, possibly due to the higher adsorption and/or lower bioavailability of herbicides in this soil with a higher organic carbon content. The decrease was also greater under CT conditions than under NT conditions because the herbicides can be intercepted by the mulch, with less reaching the soil. These changes involved evolution of the structure of the microbial community.

The changes of physicochemical and biochemical parameters of a silty loam (S1) and sandy loam (S2) vineyard soils added with spent mushroom substrate (SMS) or SMS composted with ophite (OF) as rock dust (SMS + OF) were studied. Two doses of SMS or SMS + OF (25 and 100 Mg ha-1) were applied for two consecutive years (2020-2021) and changes of soil physicochemical parameters, and dehydrogenase activity (DHA), respiration (RES), microbial biomass (BIO), and the phospholipid fatty acids (PLFAs) profile were assayed on a temporal basis. The results showed an increase in soil organic carbon (OC) content, total and mineralised N, P, and K, especially when the highest SMS dose was applied to soils. Repeated application caused OC content over time up to 2.3 times higher than initial content in the silty loam soil. This increase was not observed in sandy soil, possibly due to a higher bioavailability of OC, as indicated by the evolution of extractable humic acid/fulvic acid pools. In both soils, all biochemical parameters increased after amendment, being favoured both by the OC and by the presence of OF. Significant positive correlations were found between DHA, RES and BIO, and OC content especially in the first part and then levelled off after the second dose application. Total bacterial or fungal PLFAs patterns reflected the variation of BIO by SMS application. The higher growth of fungi vs. bacterial community in amended soils was recorded after the first SMS application, although the opposite effect occurred after the second application, with similar results in both soils. The findings indicate that the application of SMS or SMS + OF in vineyard soils could be an appropriate agronomic management practice for maintaining soil sustainability, although doses and application times of these amendments should first be evaluated depending on soil texture.

Los herbicidas son esenciales para combatir las malas hierbas en los cultivos extensivos y mantener el rendimiento de los sistemas agrarios. Sin embargo, la aplicación de residuos orgánicos al suelo como enmiendas puede modificar la disipación y persistencia de estos compuestos en el suelo y su impacto medioambiental. Los residuos de herbicidas aplicados en el cultivo primario (cereal) pueden resultar fitotóxicos para los cultivos de rotación, siendo necesario estudiar la disipación de estos compuestos en distintos suelos bajo diferentes prácticas agronómicas. El objetivo de este trabajo fue estudiar el efecto de diferentes tratamientos (aplicación de enmienda orgánica, diferentes dosis de herbicida y régimen de riego) en la disipación y persistencia del herbicida aminopiralid aplicado en post-emergencia en el cultivo de trigo en dos suelos agrícolas bajo condiciones controladas en invernadero. Dos suelos con diferente contenido en carbono orgánico (CO) y pH (SA, franco, CO=0.43%, pH=4.4 y SB, franco arenoso, CO=1.12, pH=6.2) se tomaron de la finca experimental Muñovela del IRNASACSIC y se enmendaron con compost vegetal (GC) al 2.5% (p/p) (SA+GC y SB+GC). El trigo se sembró en macetas con los suelos sin enmendar y enmendados. Cada suelo recibió dos regímenes de riego (Rmed, riego medio y Rmín, riego mínimo) y dos dosis de aplicación del herbicida (D1, dosis agronómica y D2, doble de la dosis agronómica). Se establecieron 6 réplicas para cada uno de los 16 tratamientos. El porcentaje de herbicida remanente en muestras del tramo superficial de todas las macetas se determinó por HPLC-MS a distintos tiempos (0-56 días) y las curvas de disipación se ajustaron a distintos modelos cinéticos para calcular los tiempos de vida media (DT50) [1]. Las curvas de disipación se ajustaron en su mayoría al modelo de primer orden, excepto para 6 tratamientos en los que se ajustaron al modelo de primer orden multicompartimental [1]. La velocidad de disipación de aminopiralid fue mayor

The conservation agriculture (NT) is a current agricultural practice characterized by no tillage, the use of cover crops and accumulation of their residues on the soil surface (mulching). This type of agriculture can induce changes in the soil physical, chemical and biological properties, which can strongly modify herbicides dissipation compared to that in a conventional tillage system (CT). The objective of this work was to study at field scale: i) the dissipation of the herbicides S-metolachlor (SMOC), foramsulfuron (FORAM) and thiencarbazone-methyl (THIEN), ii) the formation of metabolites, and iii) the soil dehydrogenase activity (DHA) in both conventional (CT) and conservation (NT) tillage practices to analyse the effect of herbicides and type of farming practice on soil microbial activity in an agricultural soil with two different surface organic carbon contents (S1 and S2). Herbicide dissipation curves were fitted to a single first-order (SFO) kinetic model or a first-order multi-compartment (FOMC) model. Herbicide half-life (DT50) values were calculated for each of the treatments tested. Soil DHA in each of the tested treatments was determined on fresh soil samples. Herbicide dissipation was faster in NT than in CT soils, taking place mainly on the mulch surface. The DT50 values under CT varied in the range: 20.9-30.2 (SMOC), 5.0-8.8 (FORAM) and 18.7-25.2 (THIEN) days, with a dissipation order of : FORAM > THIEN > SMOC. Under NT, the DT50 values varied in the range: 4.0-1.7 (SMOC) , 3.7-5.1 (FORAM) and 6.6-5.2 (THIEN) days, following the dissipation order of : FORAM ≈ SMOC >THIEN (S1+NT), and SMOC> THIEN ≈ FORAM (S2+NT). The lower amount of metabolites observed in the soils under NT agreed with the lower amount of herbicides that reached the soil surface as a result of their partial interception by the mulch. Soil DHA was higher in soils untreated with herbicide and under NT condition

Los herbicidas son esenciales para combatir las malas hierbas en los cultivos extensivos y mantener el rendimiento de los sistemas agrarios. Sin embargo, la aplicación de residuos orgánicos al suelo como enmiendas puede modificar la disipación y persistencia de estos compuestos en el suelo y su impacto medioambiental. Los residuos de herbicidas aplicados en el cultivo primario (cereal) pueden resultar fitotóxicos para los cultivos de rotación, siendo necesario estudiar la disipación de estos compuestos en distintos suelos bajo diferentes prácticas agronómicas. El objetivo de este trabajo fue estudiar el efecto de diferentes tratamientos (aplicación de enmienda orgánica, diferentes dosis de herbicida y régimen de riego) en la disipación y persistencia del herbicida aminopiralid aplicado en post-emergencia en el cultivo de trigo en dos suelos agrícolas bajo condiciones controladas en invernadero. Dos suelos con diferente contenido en carbono orgánico (CO) y pH (SA, franco, CO=0.43%, pH=4.4 y SB, franco arenoso, CO=1.12, pH=6.2) se tomaron de la finca experimental Muñovela del IRNASACSIC y se enmendaron con compost vegetal (GC) al 2.5% (p/p) (SA+GC y SB+GC). El trigo se sembró en macetas con los suelos sin enmendar y enmendados. Cada suelo recibió dos regímenes de riego (Rmed, riego medio y Rmín, riego mínimo) y dos dosis de aplicación del herbicida (D1, dosis agronómica y D2, doble de la dosis agronómica). Se establecieron 6 réplicas para cada uno de los 16 tratamientos. El porcentaje de herbicida remanente en muestras del tramo superficial de todas las macetas se determinó por HPLC-MS a distintos tiempos (0-56 días) y las curvas de disipación se ajustaron a distintos modelos cinéticos para calcular los tiempos de vida media (DT50) [1]. Las curvas de disipación se ajustaron en su mayoría al modelo de primer orden, excepto para 6 tratamientos en los que se ajustaron al modelo de primer orden multicompartimental [1]. La velocidad de disipación de aminopiralid fue mayor

[EN] Herbicides used on primary crops can be phytotoxic to rotational crops, being necessary to study their behavior in soils under different pedoclimatic and agronomic conditions. In this work, the effect of the application of green compost, two doses of herbicide and irrigation regimes on the dissipation of the herbicide iodosulfuron-methyl sodium in two agricultural soils with wheat cultivation in greenhouse was studied. Soils with higher organic carbon (OC) content and pH showed higher dissipation rates and lower half-life values (DT50). Herbicide dose had no significant effect on herbicide dissipation. Soils under minimum irrigation showed lower dissipation rates and higher persistence. A higher concentration of herbicide remaining in the topsoil layer of the pot was found. The amended soils, treated with the high herbicide dose and minimum irrigation, presented greater persistence in the soils., [ES] Los herbicidas utilizados en los cultivos primarios pueden resultar fitotóxicos para los cultivos de rotación, siendo necesario estudiar su comportamiento en los suelos bajo diferentes condiciones edafoclimáticas y agronómicas. En este trabajo se estudió el efecto de la aplicación de compost vegetal, dos dosis de herbicida y regímenes de riego en la disipación del herbicida iodosulfuron-metil sodio en dos suelos agrícolas con cultivo de trigo en invernadero. Los suelos con mayor contenido en carbono orgánico (CO) y pH presentaron mayor velocidad de disipación y menores valores de vida media (DT50). La dosis de herbicida no tuvo efecto significativo sobre la disipación del herbicida. Los suelos con riego mínimo presentaron menor velocidad de disipación y mayor persistencia. Se encontró una mayor concentración de herbicida remanente en el tramo superficial de la maceta. Los suelos enmendados, tratados con la dosis alta de herbicida y riego mínimo, presentaron mayor persistencia en los suelos.

Se estudió el efecto de la aplicación simultánea de tres herbicidas ampliamente utilizados en cultivos de cereales y/o frecuentemente encontrados en las aguas superficiales y/o subterráneas, clortoluron (CTL), flufenacet (FNC) y diflufenican (DFN); y dos residuos orgánicos, sustrato postcultivo de hongos (SMS) y compost verde (GC), añadidos a un suelo cultivado con trigo de invierno como enmiendas orgánicas, en el transporte de estos compuestos en el suelo en parcelas experimentales bajo condiciones de campo, a partir de la evaluación de la disipación, persistencia, distribución y/o movilidad de los herbicidas en el perfil del suelo sin enmendar y enmendado, la modelización de su comportamiento a partir de la utilización de los modelos matemáticos PRZM y MACRO con el fin de predecir a largo plazo el impacto medioambiental en la calidad de las aguas bajo este tipo de escenarios, y la influencia de esta práctica agronómica en las comunidades microbianas del suelo como indicadores de la calidad y conservación del suelo. Las enmiendas orgánicas aumentaron la capacidad de retención de agua por el horizonte superficial del suelo ralentizando la percolación y lixiviación de los compuestos químicos en el perfil del suelo. El contenido de CO y COD aportado por las enmiendas orgánicas al suelo tuvo un efecto opuesto sobre la dinámica de los herbicidas. Mientras que el CO aumentó la adsorción y/o persistencia de los herbicidas en las capas superiores del suelo, disminuyendo su movilidad (especialmente para FNC), el COD aumentó la biodisponibilidad de los herbicidas en solución para ser degradados y su movilidad a horizontes más profundos del suelo (especialmente para CTL) en ambos periodos experimentales.En general, las enmiendas orgánicas provocaron un cambio significativo en la comunidad microbiana del suelo independientemente de los herbicidas, y fueron útiles para amortiguar los efectos de estos compuestos sobre la biomasa y la actividad microbiana del suelo, así como para

Organic wastes applied as composted amendments may improve the quality of degraded soils and modify the fate of pesticides. This work has set out to study the dissipation kinetics of the herbicides chlorotoluron and flufenacet during their second-year application in field experimental plots with a sandy-loam agricultural soil without amendment (S) and amended with spent mushroom substrate (S + SMS) or green compost (S + GC). The SMS and GC were applied to the soil during the previous winter’s wheat crop campaign (1 year before the second herbicide application) at rates of 140 and 85 t ha−1 (dry weight basis), respectively. The experiment involved randomized complete blocks with plots of 81 m2, including three replicates per soil treatment. Surface soils were sampled after herbicide application for 225 days, and herbicide residues in the soil samples were determined by HPLC-MS. The dissipation curves of both herbicides for the three soil treatments were better fitted to the first order multi-compartment (FOMC) kinetic model. The dissipation rates of the most hydrophobic herbicide, flufenacet, were slower than those for chlorotoluron in both unamended and amended soils. The half-life (DT50) values ranged between 20.7 to 41.1 days for chlorotoluron, and 42.9 to 75.6 days for flufenacet, and they followed the order S > S + SMS > S + GC. The DT50 values of chlorotoluron were close for S + SMS and S + GC, and the DT50 of flufenacet for S was similar to that for S + SMS. These DT50 values decreased up to four times with respect to those calculated after the first application indicating an accelerated dissipation of the herbicides after the second application especially in amended soil in comparison with unamended soil. The persistence of chlorotoluron and flufenacet in an agricultural soil was modified by the effect of the organic amendments, weather conditions, and possibly the repeated application of the compounds under real field conditions

The management of large volumes of organic residues generated in different livestock, urban, agricultural and industrial activities is a topic of environmental and social interest. The high organic matter content of these residues means that their application as soil organic amendments in agriculture is considered one of the more sustainable options, as it could solve the problem of the accumulation of uncontrolled wastes while improving soil quality and avoiding its irreversible degradation. However, the behavior of pesticides applied to increase crop yields could be modified in the presence of these amendments in the soil. This review article addresses how the adsorption–desorption, dissipation and leaching of pesticides in soils is affected by different organic residues usually applied as organic amendments. Based on the results reported from laboratory studies, the influence on these processes has been evaluated of multiple factors related to organic residues (e.g., origin, nature, composition, rates, and incubation time of the amended soils), pesticides (e.g., with different use, structure, characteristics, and application method), and soils with different physicochemical properties. Future perspectives on this topic are also included for highlighting the need to extend these laboratory studies to field and modelling scale to better assess and predict pesticide fate in amended soil scenarios.

The soil microbial activity, biomass and structure were evaluated in an unamended (S) and organically amended soil treated with two commercial formulations of the herbicides chlorotoluron (Erturon®) and flufenacet plus diflufenican (Herold®) under field conditions. Soils were amended with spent mushroom substrate (SMS) or green compost (GC). Soil microbial dehydrogenase activity (DHA), biomass and structure determined by the phospholipid fatty acid (PLFA) profiles were recorded at 0, 45, 145, 229 and 339 days after herbicide treatment. The soil DHA values steadily decreased over time in the unamended soil treated with the herbicides, while microbial activity was constant in the amended soils. The amended soils recorded higher values of concentrations of PLFAs. Total soil microbial biomass decreased over time regardless of the organic amendment or the herbicide. Herbicide application sharply decreased the microbial population, with a significant modification of the microbial structure in the unamended soil. In contrast, no significant differences in microbial biomass and structure were detected in S + SMS and S + GC, untreated or treated with herbicides. The application of SMS and GC led to a significant shift in the soil microbial community regardless of the herbicides. The use of SMS and GC as organic amendments had a certain buffer effect on soil DHA and microbial biomass and structure after herbicide application due to the higher adsorption capacity of herbicides by the amended soils.

This paper reports the mobility and total balance of chlorotoluron (CTL), flufenacet (FNC) and bromide ion (Br−) throughout a sandy soil profile after the application of spent mushroom substrate (SMS) and green compost (GC). Obtaining mobility dataset is crucial to simulate the herbicides' fate under amended soil scenarios by application pesticide leaching models with regulatory application (FOCUS models). The application of organic residues is nowadays increased to improve the crop yields and there is a gap in the simulations of this kind of amended scenarios. A two-year field experiment involving unamended soil (S) and SMS- or GC-amended soil plots was conducted. CTL, FNC, and Br− were annually applied and their residual concentrations were determined in soil profiles (0–100 cm) regularly sampled. In all the treatments the order of mobility is followed as FNC < CTL < Br−. SMS and GC increased herbicide retention in the top 10 cm by the higher organic carbon (OC) content than the unamended soil, and their ability to increase the soil's water-holding capacity and to decrease water percolation. Simultaneously dissolved organic carbon (DOC) content facilitated herbicide transport being it favoured by the initial soil moisture content and the rainfall shortly after the chemicals' initial application. Over the first year, residual amounts (<2.6%) of Br−, CTL and FNC were leached down to 90–100 cm depth in the three treatments. However, over the second year low CTL and FNC amounts (<1.0%) reached the bottom layer only in S + SMS although high Br− concentrations did so in the three treatments (<20%). According to the total balance of Br−, CTL, and FNC in the soil profiles other processes (degradation, mineralisation, bound residues formation, and/or crop uptake) different from leaching below 1 m depth might play a key role in their dissipation especially in the amended soil profiles. SMS and GC are likely to be used as organic amendments to preserve the soil and water qua

Addition of organic residues to soil is a current farming practice but it is not considered in the modelling studies for pesticide risk assessment at regulatory level despite its potential impact on the pesticide dynamics in soil. Thus, the objective of this work was to examine and to compare the ability of PRZM and MACRO pesticide fate models to simulate soil water content, and bromide (Br−, tracer), chlorotoluron and flufenacet concentrations in the soil profiles (0–100 cm) of one agricultural soil, unamended (control soil, S), amended with spent mushroom substrate (S + SMS) or amended with green compost (S + GC). Based on a two-year field-scale dataset, the models were first calibrated against measurements of water and solutes contents in the soil profiles (first year) and then tested without any further model calibration by comparison with the field observations of the second year. In general, the performance of MACRO to simulate the whole dataset in the three soil treatments was higher than that of PRZM. MACRO simulated satisfactorily the water dynamics along the soil profiles whereas it was poorly described by the capacity model PRZM. Both models predicted very well the Br− mobility in control and amended soils after dispersion parameters were fitted to observations. No calibration was necessary to reproduce correctly herbicides vertical distribution in the control soil profile. In the amended soils, MACRO simulations were highly correlated to the observed vertical distribution of flufenacet and chlorotoluron, but calibration of the Kd of chlorotoluron was needed. On the contrary, modelling with PRZM required calibration of Kd and DT50 of both herbicides to obtain an acceptable agreement between observations and predictions in the amended soils. Kd and DT50 calibration was based on the initial dissolved organic carbon contents (DOC) of amended soils. It allowed to take into account the processes that decrease the herbicides sorption on the soil and enhance the

The dissipation and persistence of two cereals herbicides, chlorotoluron and flufenacet, were studied in a field experiment including three replicated plots of unamended soil (S), soil amended with spent mushroom substrate (S + SMS), and soil amended with green compost (S + GC), during the winter wheat cultivation campaign. The SMS and GC organic residues were applied to the soil at rates of 140 or 85 t residue ha−1, and herbicides were sprayed as Erturon® and Herold® formulations for chlorotoluron and flufenacet, respectively. Concentrations of both herbicides and of their metabolites were regularly measured in the three soil treatments (0–10 cm) from 0 to 339 days. The dissipation kinetics fitted well the single first order (SFO) model, except that of chlorotoluron that fitted the first order multi-compartment (FOMC) model better in the unamended soil. The dissipation rates of herbicides were lower in amended than in unamended soils. The results also showed that the DT50 of chlorotoluron (66.2–88.0 days) and flufenacet (117–145 days) under field conditions were higher than those previously obtained at laboratory scale highlighting the importance of the changing environmental conditions on the dissipation process. Similarly, the formation of chlorotoluron and flufenacet metabolites under field conditions was different from that previously observed in the laboratory. The performance of the MACRO pesticide fate model, parameterized with laboratory data, was then tested against field data. There was a very good agreement between measured and simulated chlorotoluron residue levels in the three soil treatments, while the ability of the model to reproduce the dissipation of flufenacet was good in the unamended soil and very good in S + SMS and S + GC soils. MACRO might be used to estimate the remaining amounts of herbicides in amended soils from degradation data previously obtained at laboratory scale. This would help to manage herbicide doses in different environmental

In recent years there is growing evidence of the importance of the Smithian-Spathian (Early Triassic) ecological crisis to explain the delayed recovery of life after the Permian-Triassic Boundary mass extinction. This study focuses on sedimentary continental rocks of middle Permian to Middle Triassic age from four different Peritethys basins in subequatorial latitudes. Similar distribution patterns of aluminum phosphate-sulfate (APS) minerals contents in these rocks in the four studied basins provide evidence of increased acidity during the Smithian-Spathian transition, coinciding with a lack of indicators of organic activity in the same interval. Thus, this period of high acidity on land, may have been one of the causes of this biological crisis. Based on the quantification of APS minerals in the studied sedimentary sequences, we propose that it was not until acidity in the environment diminished, that biotic recovery was possible. APS data may also be useful to interpret other past biotic crises.

A laboratory study was designed to assess the following: i) the degradation kinetics of chlorotoluron and flufenacet at two different temperatures, 6 °C and 16 °C, in an unamended agricultural soil and one amended with spent mushroom substrate (SMS) and green compost (GC), and ii) the formation of the main metabolites of both herbicides with potential risk for water pollution over degradation time. The aim was to determine the dependence of these herbicide degradations on temperature (Q10 factor) using kinetic parameters, which is essential information for the later simulation of herbicide environmental fate with FOCUS models. SMS and GC were applied in situ to the natural soil as organic amendments at rates of 140 or 85 t residue ha−1, respectively. Unamended and amended soils were taken from the 0–10 cm topsoil of experimental plots (three replicates/treatment) located on an agricultural farm. Samples of soil + herbicides were incubated at 6 °C or 16 °C under laboratory conditions. The degradation curves of chlorotoluron and flufenacet were fitted to single first-order and first-order multicompartment kinetic models, respectively. The flufenacet degradation, the more hydrophobic herbicide, was slower than that of chlorotoluron in all the treatments. The application of the organic amendments to soil increased the half-lives (DT50) for both herbicides incubated at 6 °C (1.3–1.9 times) and 16 °C (1.4–1.9 times) due to their higher sorption and lower bioavailability for degradation in amended soils. The herbicides recorded a faster degradation at 16 °C than at 6 °C (Q10 = 1.9–2.8) due to the increased microbial biomass and/or activity with temperature. The metabolites desmethyl chlorotoluron, flufenacet ESA and flufenacet OA were detected in all the soil treatments at both incubation temperatures. The determination of Q10 factors in amended soils is very valuable for generating accurate input data for pesticide fate models such as FOCUS in order to improve the evaluat