Plastic debris is accumulating in agricultural land due to the increased use of plastic mulches, which is causing serious environmental problems, especially for biochemical and physical properties of ...the soil. Dissolved organic matter (DOM) plays a central role in driving soil biogeochemistry, but little information is available on the effects of plastic residues, especially microplastic, on soil DOM. We conducted a soil-incubation experiment in a climate-controlled chamber with three levels of microplastic added to loess soil collected from the Loess Plateau in China: 0% (control, CK), 7% (M1) and 28% (M2) (w/w). We analysed the soil contents of dissolved organic carbon (DOC), dissolved organic nitrogen (DON), NH4+, NO3−, dissolved organic phosphorus (DOP), and PO43− and the activities of fluorescein diacetate hydrolase (FDAse) and phenol oxidase. The higher level of microplastic addition significantly increased the nutrient contents of the DOM solution. The lower level of addition had no significant effect on the DOM solution during the first seven days, but the rate of DOM decomposition decreased in M1 between days 7 and 30, which increased the nutrient contents. The microplastic facilitated the accumulation of high-molecular-weight humic-like material between days 7 and 30. The DOM solutions were mainly comprised of high-molecular-weight humic-like material in CK and M1 and of high-molecular-weight humic-like material and tyrosine-like material in M2. The Microplastic stimulated the activities of both enzymes. Microplastic addition thus stimulated enzymatic activity, activated pools of organic C, N, and P, and was beneficial for the accumulation of dissolved organic C, N and P.
•Microplastic addition stimulated soil activity of fluorescein diacetate hydrolase (FDAse) in soil.•The lower level of microplastic addition had a negligible effect on the nutrient contents in DOM solution at day 30.•The higher level of microplastic addition significantly increased the nutrient contents in DOM solution.
Pesticide use is a major foundation of the agricultural intensification observed over the last few decades. As a result, soil contamination by pesticide residues has become an issue of increasing ...concern due to some pesticides' high soil persistence and toxicity to non-target species. In this study, the distribution of 76 pesticide residues was evaluated in 317 agricultural topsoil samples from across the European Union. The soils were collected in 2015 and originated from 11 EU Member States and 6 main cropping systems. Over 80% of the tested soils contained pesticide residues (25% of samples had 1 residue, 58% of samples had mixtures of two or more residues), in a total of 166 different pesticide combinations. Glyphosate and its metabolite AMPA, DDTs (DDT and its metabolites) and the broad-spectrum fungicides boscalid, epoxiconazole and tebuconazole were the compounds most frequently found in soil samples and the compounds found at the highest concentrations. These compounds occasionally exceeded their predicted environmental concentrations in soil but were below the respective toxic endpoints for standard in-soil organisms. Maximum individual pesticide content assessed in a soil sample was 2.05 mg kg−1 while maximum total pesticide content was 2.87 mg kg−1. This study reveals that the presence of mixtures of pesticide residues in soils are the rule rather than the exception, indicating that environmental risk assessment procedures should be adapted accordingly to minimize related risks to soil life and beyond. This information can be used to implement monitoring programs for pesticide residues in soil and to trigger toxicity assessments of mixtures of pesticide residues on a wider range of soil species in order to perform more comprehensive and accurate risk assessments.
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•76 residues of pesticides were analyzed in 317 EU agricultural topsoils.•83% of the soils contained 1 or more residues, 58% contained mixtures.•166 different mixtures were identified.•Predicted concentrations of individual residues were occasionally exceeded.•The combined effects of residue mixtures need to be assessed.
High-intensity and fast-spreading wildfires are natural in the Mediterranean basin. However, since 1960, wildfire occurrence has increased because of changes in land use, which resulted in extensive ...land abandonment, increases in the fuel load and continuity in the landscape. The level of soil degradation related to wildfire occurrence depends on fire recurrence, topography of the site, intensity of the soil erosion processes and plant cover post-fire regeneration rate. Therefore assessing fire impacts on soil properties is critical to quantify land degradation processes and to assess post-fire restoration plans. This article reviews the changes in soil nutrient status of Mediterranean ecosystems affected by wildfires by focusing on the interactions between the different drivers and factors, and the underlying processes of these changes. Articles dealing with wildfires in areas belonging to the Mediterranean basin and characterized by an annual average rainfall of 300–900mm and a mean annual temperature around 14–19°C, have been reviewed. The data show that the soil nutrient content in Mediterranean drylands affected by wildfires depends on the vegetation type, fire recurrence and fire intensity. Immediately after a fire, the nutrient content in both the O and A horizons often increases because of ash deposition, nutrient release from the burnt vegetation and formation of stable nutrient forms. Ash deposition persistence on the soil surface is one of the most important factors in determining the soil nutrient content both immediately after a fire and for the long-term. For the restoration of burned habitats it is important to know the content and the spatial distribution of nutrients in the soil because this can act as a limiting factor to vegetation recovery. Carbon and nitrogen pools in the soil have been recognized as fundamental to vegetation recuperation after a fire. To promote the accumulation and retention of nutrients in soil after a fire, it is important to stabilize the burnt site by applying post-fire measures that limit soil erosion, surface runoff and wind loss of the ash. Depending on the plant species and the time elapsing between consecutive wildfires, fire is responsible for the transition from mature ecosystems (i.e. conifer forests) to shrublands, which are poorer in soil nutrient status. Wildfire occurrence can be reduced by planting fire-resilient plants in fire-prone areas. To define the best post-fire and restoration treatments, the impacts of fire on both the O and the A horizon as well as the impacts of different post-fire treatments on the soil nutrient content require further study.
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•Characteristics and recommended use rates of 230 EU-approved pesticides are listed.•All the 230 active substances considered are hazardous to humans and/or ecosystems.•None of the ...230 approved substances have complete hazard profiles.•124 out of the 230 active substances are top use or top hazard substances.•Strong restrictions are needed to match the Farm to Fork pesticide reduction goals.
The recently released Farm to Fork Strategy of the European Union sets, for the first time, pesticide reduction goals at the EU level: 50% reduction in overall use and risk of chemical pesticides and a 50% use reduction of more hazardous pesticides. However, there is little guidance provided as to how to achieve these targets. In this study, we compiled the characteristics of all 230 EU-approved, synthetic, open-field use active substances (AS) used as herbicides, fungicides and insecticides, and explored the potential of seven Farm to Fork-inspired pesticide use reduction scenarios to achieve the 50% reduction goals. The pesticide reduction scenarios were based on recommended AS application rates, pesticide type, soil persistence, presence on the candidate for substitution list, and hazard to humans and ecosystems. All 230 AS have been found to cause negative effects on humans or ecosystems depending on exposure levels. This is found despite the incomplete hazard profiles of several AS. ‘No data available’ situations are often observed for the same endpoints and specific organisms. The results of the scenarios indicate that only severe pesticide use restrictions, such as allowing only low-hazard substances, will result in the targeted 50% use and risk reductions. Over half of the 230 AS considered are top use or top hazard substances, however, the reduction actions depend on the still to be defined EC priority areas and action plans, also for other recent and related strategies. Broader scenario implications (on productivity, biodiversity or economy) and the response of farmers to the pesticide use restrictions should be explored in those plans to define effective actions. Our results emphasize the need for a re-evaluation of the approved AS and of their representative uses, and the call for open access to AS, crop and region-specific use data to refine scenarios and assess effective reductions.
Considering that pesticides have been used in Europe for over 70 years, a system for monitoring pesticide residues in EU soils and their effects on soil health is long overdue. In an attempt to ...address this problem, we tested 340 EU agricultural topsoil samples for multiple pesticide residues. These samples originated from 4 representative EU case study sites (CSS), which covered 3 countries and four of the main EU crops: vegetable and orange production in Spain (S–V and S–O, respectively), grape production in Portugal (P-G), and potato production in the Netherlands (N–P). Soil samples were collected between 2015 and 2018 after harvest or before the start of the growing season, depending on the CSS. Conventional and organic farming results were compared in S–V, S–O and N–P. Soils from conventional farms presented mostly mixtures of pesticide residues, with a maximum of 16 residues/sample. Soils from organic farms had significantly fewer residues, with a maximum of 5 residues/sample. The residues with the highest frequency of detection and the highest content in soil were herbicides: glyphosate and its main metabolite AMPA (P-G, N–P, S–O), and pendimethalin (S–V). Total residue content in soil reached values of 0.8 mg kg−1 for S–V, 2 mg kg−1 for S–O and N–P, and 12 mg kg−1 for P-G. Organic soils presented 70–90% lower residue concentrations than the corresponding conventional soils. There is a severe knowledge gap concerning the effects of the accumulated and complex mixtures of pesticide residues found in soil on soil biota and soil health. Safety benchmarks should be defined and introduced into (soil) legislation as soon as possible. Furthermore, the process of transitioning to organic farming should take into consideration the residue mixtures at the conversion time and their residence time in soil.
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•Pesticide residues werewe identified in EU soils of Organic/Conventional farms.•Total pesticide content in O-soils was 70–90% lower than in C-soils.•>70% of C-soils had mixtures of pesticide residues, maximal 16 residues/sample.•O-soils contained mainly mixtures of 2–5 residues, maximal 5 residues/sample.•Risk assessment of mixtures and related soil benchmarks are urgently required.
Approval for glyphosate-based herbicides in the European Union (EU) is under intense debate due to concern about their effects on the environment and human health. The occurrence of glyphosate ...residues in European water bodies is rather well documented whereas only few, fragmented and outdated information is available for European soils. We provide the first large-scale assessment of distribution (occurrence and concentrations) of glyphosate and its main metabolite aminomethylphosphonic acid (AMPA) in EU agricultural topsoils, and estimate their potential spreading by wind and water erosion. Glyphosate and/or AMPA were present in 45% of the topsoils collected, originating from eleven countries and six crop systems, with a maximum concentration of 2mgkg−1. Several glyphosate and AMPA hotspots were identified across the EU. Soil loss rates (obtained from recently derived European maps) were used to estimate the potential export of glyphosate and AMPA by wind and water erosion. The estimated exports, result of a conceptually simple model, clearly indicate that particulate transport can contribute to human and environmental exposure to herbicide residues. Residue threshold values in soils are urgently needed to define potential risks for soil health and off site effects related to export by wind and water erosion.
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•Data on occurrence and levels of glyphosate residues in EU soils is very limited.•Glyphosate and its metabolite AMPA were tested in 317 EU agricultural topsoils.•21% of the tested EU topsoils contained glyphosate, and 42% contained AMPA.•Both glyphosate and AMPA had a maximum concentration in soil of 2mgkg−1.•Some contaminated soils are in areas highly susceptible to water and wind erosion.
Context
From 1999 onwards, China has initiated a large-scale landscape restoration project in the Chinese Loess Plateau, which has had profound but variable impacts on the local ecosystem services ...supply. The dynamics of ecosystem services throughout the restoration process remain poorly understood.
Objectives
To analyze the spatial and temporal dynamics in ecosystem services before and after the implementation of the land restoration project, and to understand trade-offs and synergies between multiple ecosystem services.
Methods
We used the InVEST model and statistical yearbook data to quantify the ecosystem services over the period 1990–2018 for the Yan’an area and applied the concept of ecosystem service bundles to understand the dynamics of 11 ecosystem services over its 13 constituent counties.
Results
A significant increase of fruit production, sediment retention, habitat quality, aesthetic landscape value, and learning and inspiration value was found over time in the Yan’an area, while a decrease of timber production and water yield was also observed. The majority of the county-level ecosystem service bundles were transformed from having a focus on timber production to aesthetic landscape value. The dynamics of ecosystem services change induced by land restoration was discovered to start with increasing regulating services at the expense of provisioning services, while cultural services exceeded regulating services and occupied the main proportion subsequently.
Conclusion
Both trade-offs and synergies were found between provisioning, regulating and cultural services. Implementation of the large-scale restoration project is recognized as a key driving force inducing change of ecosystem services, starting with an improvement of regulating services followed by a gradually evolving prominence of cultural services.
Proper pesticide use is crucial to farmers' health and environmental protection. However, the factors affecting a farmer's behaviour with regards to pesticide use remain largely unknown in ...Bangladesh, particularly for vegetable farmers. Hence, we investigated the use of pesticides by vegetable growers amongst 101 households in an intensive vegetable growing area of Jamalpur district in Bangladesh. Each farmer's background, knowledge, attitude, health problems, experience, protective behaviour, and pesticide use were collected in order to examine the behavioural activities of farmers in relation to their pesticide use and to identify the related factors effecting use. The majority of vegetable growers have long term experience with pesticide use and are involved in full-time vegetable growing. However, even with this long term experience, these growers continue to suffer with toxicity symptoms during pesticide application. Vomiting and headaches are the most frequent symptoms. Amongst eight possible protective behaviours (PBs) reported to be known by the farmers, only three were frequently adopted. The low educational level, the lack of knowledge, insufficient training and the pursuit of high profits were found to be the main reasons for the inadequate use of PBs. The PBs of the vegetable growers were highly affected by their knowledge and past experiences of toxicity. The PBs were also weakly affected by the farmers' attitude towards pesticide use. Community-based participatory training and education programmes for farmers need to cover both content and process dimensions as well as focus on both on-season and off-season training, specifically targeting woman and elder farmers. Focus group discussions, learn-by-experience examples, photographs and experience sharing can be employed in training and education programmes for improving the farmers' PBs.
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•Pesticide use behaviour of vegetable farmers in Bangladesh and related factors were studied.•Protective behaviour was greatly affected by knowledge and past experiences of toxicity.•Vomiting and headaches were the most frequently experienced toxicity symptoms of farmers.•A large gap exists between the knowledge of potential pesticide risks and pesticide application.•Community-based training and education focused on farmers' management practices could bridge the gap.
The intensive use of pesticide and plastic mulches has considerably enhanced crop growth and yield. Pesticide residues and plastic debris, however, have caused serious environmental problems. This ...study investigated the effects of the commonly used herbicide glyphosate and micrometre-sized plastic debris, referred as microplastics, on glyphosate decay and soil microbial activities in Chinese loess soil by a microcosm experiment over 30 days incubation. Results showed that glyphosate decay was gradual and followed a single first-order decay kinetics model. In different treatments (with/without microplastic addition), glyphosate showed similar half-lives (32.8 days). The soil content of aminomethylphosphonic acid (AMPA), the main metabolite of glyphosate, steadily increased without reaching plateau and declining phases throughout the experiment. Soil microbial respiration significantly changed throughout the entirety of the experiment, particularly in the treatments with higher microplastic addition. The dynamics of soil β-glucosidase, urease and phosphatase varied, especially in the treatments with high microplastic addition. Particles that were considerably smaller than the initially added microplastic particles were observed after 30 days incubation. This result thus implied that microplastic would hardly affect glyphosate decay but smaller plastic particles accumulated in soils which potentially threaten soil quality would be further concerned especially in the regions with intensive plastic mulching application.
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•Influence of MP on glyphosate decay and soil microbial activities were conducted.•No effect of microplastic on glyphosate degradation was observed.•Glyphosate followed SFO decay kinetics model, with 32.8 days of half-life time.•Soil microbial activities significantly changed with MP addition.•Particle sizes of MP differed significantly in this short-term incubation study.
Microplastic hardly affected herbicide glyphosate decay in soil but soil microbial activities which, in turn, would indirectly influence pesticide behaviour in soil ecosystem.
The dissipation kinetics of glyphosate and its metabolite aminomethylphosphonic acid (AMPA) were studied in loess soil, under biotic and abiotic conditions, as affected by temperature, soil moisture ...(SM) and light/darkness. Nonsterile and sterile soil samples were spiked with 16mgkg−1 of glyphosate, subjected to three SM contents (20% WHC, 60% WHC, saturation), and incubated for 30days at 5°C and 30°C, under dark and light regimes. Glyphosate and AMPA dissipation kinetics were fit to single-first-order (SFO) or first-order-multicompartment (FOMC) models, per treatment combination. AMPA kinetic model included both the formation and decline phases. Glyphosate dissipation kinetics followed SFO at 5°C, but FOMC at 30°C. AMPA followed SFO dissipation kinetics for all treatments. Glyphosate and AMPA dissipation occurred mostly by microbial activity. Abiotic processes played a negligible role for both compounds. Under biotic conditions, glyphosate dissipation and AMPA formation/dissipation were primarily affected by temperature, but also by SM. Light regimes didn't play a significant role. Glyphosate DT50 varied between 1.5 and 53.5days, while its DT90 varied between 8.0 and 280days, depending on the treatment. AMPA persisted longer in soil than glyphosate, with its DT50 at 30°C ranging between 26.4 and 44.5days, and its DT90 between 87.8 and 148days. The shortest DT50/DT90 values for both compounds occurred at 30°C and under optimal/saturated moisture conditions, while the largest occurred at 5°C and reaching drought stress conditions. Based on these results, we conclude that glyphosate and AMPA dissipate rapidly under warm and rainy climate conditions. However, repeated glyphosate applications in fallows or winter crops in countries where cold and dry winters normally occur could lead to on-site soil pollution, with consequent potential risks to the environment and human health.
To our knowledge, this study is the first evaluating the combined effect of temperature, soil moisture and light/dark conditions on AMPA formation/dissipation kinetics and behaviour.
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•The combined effect of temp+SM+light on glyphosate & AMPA dissipation was studied in loess soil.•Glyphosate was 30 times more persistent under cold+dry than under warm+moist conditions.•AMPA persisted 21 (warm+moist) and 11 times (warm+dry) longer than glyphosate.•The use of SFO dissipation kinetics at high temperatures underestimates glyphosate DT90.•AMPA dissipation kinetics included the formation and decline phases, and followed SFO.
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