Journal of environmental quality最新文献

Phosphorus (P) budgets for cropping systems provide insights for keeping soil P at optimal levels for crops while avoiding excess inputs. We quantified 12 years of P inputs (fertilizer and atmospheric deposition) and outputs (harvest and leaching losses) for replicated maize (Zea mays L.)-soybean (Glycine max L.)-wheat (Triticum aestivum) crop rotations under conventional, no-till, reduced input, and biologically based (organic without compost or manure) management systems at the Kellogg Biological Station LTAR site in southwest Michigan. Conventional, no-till, and reduced input systems were fertilized between 13 and 50 kg P ha^-1 depending on year. Soil test phosphorus (STP) was measured at 0- to 25-cm depth every autumn. Leached P was measured as dissolved P in the soil solution sampled beneath the rooting depth and combined with modeled percolation. Fertilization and harvest were the predominant P fluxes in the fertilized systems, whereas only harvest dominated P flux in the unfertilized organic system. Leaching losses were minor terms in the budgets, but leachate concentrations were nevertheless close to the range of concern for downstream eutrophication. Over the 12-year study period, the organic system exhibited a negative P balance (-82.0 kg P ha^-1), coinciding with suboptimal STP levels, suggesting a need for P supplementation. In contrast, the fertilized systems showed positive P balances (mean: 70.1 kg P ha^-1) with STP levels well above agronomic optima. Results underscore the importance of tailored P management strategies to sustain crop productivity while mitigating environmental impacts.

The range and density of one of North America's most destructive and invasive mammalian species, wild pigs (Sus scrofa), has expanded rapidly over the past several decades. Alongside this growth, their fecal contamination of surface waters has impaired water quality through significantly increased levels of pathogenic bacteria, raising concerns over the potential for zoonotic disease transmission. Significant remediation of these water quality impacts has been shown as a result of reductions in wild pig populations due to control efforts; however, the duration of these remediation effects as populations rebound remains unclear. Our study sought to determine the longevity of water quality remediation resulting from wild pig population control efforts. We found that median concentrations of Escherichia coli and fecal coliform (CFU/100 mL) increased by 746% and 159% in the year following the conclusion of removal efforts, resulting in median concentrations of 79% and 159% greater than those observed prior. We also found increased public health risk, with samples exceeding E. coli and fecal coliform guidelines 10% and 12% more often than pre-removal, respectively. While further research into wild pig population dynamics and fecal contamination is necessary, we conclude that ongoing population control efforts may be necessary to remediate water quality impacts and public health risks associated with invasive wild pigs.

Gypsum (CaSO₄·2H₂O) is increasingly used to bind P to soil on agricultural fields, which mitigates eutrophication caused by runoff of excess PO₄ ^3- fertilizers into adjacent aquatic environments. Gypsum also binds dissolved organic matter (DOM) to soil particles. Gypsum that gets into fresh water after field applications may result in enhanced particle formation by DOM flocculation and alter C transfer in rivers draining agricultural catchments. We tested the potential effects of gypsum additions on DOM cycling by adding concentrated gypsum solution into river water before subjecting it to controlled mixing to increase particle collisions and flocculation. Gypsum addition increased the amount of suspended particulate matter in river water three to four times higher than in controls without gypsum. The flocs contained a relatively high amount of minerogenic particles. Gypsum-induced flocculation removed colored dissolved organic matter which, together with removal of minerogenic particles, may result in increased water clarity. Gypsum addition and the associated changes in the DOM pool did not affect microbial growth or DOM processing, suggesting that flocculation did not target the labile fraction of the DOM pool. While acknowledging that the responses detected in our study might depend on the region, we propose that the changes in riverine DOM cycling caused by gypsum application results in either no changes or slightly positive changes to the water quality of the rivers and should not be considered an obstacle for eutrophication prevention using gypsum applications.

Agricultural runoff often contains P in dissolved and sediment-bound forms, decreasing surface water quality. No-till and cover cropping conservation practices have been recommended for reducing erosion and nutrient loss from cropping systems. The overall aims of this study were to characterize and evaluate the effects of fertilizer (placement and source) and cover crop management on P speciation in surface runoff sediments and source soil. In 2014, a field-scale experiment was established in a no-till, corn (Zea mays L.)-soybean (Glycine max L.) cropping system with two cover crop treatments (with and without a winter crop; winter wheat [Triticum aestivum L.], rapeseed [Brassica napus L.], hairy vetch [Vicia villosa Roth], winter triticale [×Triticosecale Wittm.], and cereal rye [Secale cereale L.]) and three P fertilizer management treatments (no P, fall broadcast diammonium phosphate, and spring subsurface injected ammonium polyphosphate). Phosphorus fractionation in the source soil collected in the fall of 2019 and sediment samples collected throughout 2020 were analyzed using a modified sequential P extraction method to evaluate the cumulative effects of imposing the treatment factors over 5 years. The direct P speciation was done using X-ray absorption near edge structure spectroscopy. The indirect P speciation (fractionation) results showed that the management practices affected the exchangeable, organic matter-associated, and Fe-bound P fractions in sediments and the exchangeable and residual fractions in source soil. Direct P speciation results showed a depletion of Fe-associated P in soil and sediment from cover crop treatment, suggesting that Fe-associated P species were affected by cover crops. Changes in soil and runoff sediment P speciation would change the proportions and forms of soluble and particulate P in runoff sediments and may influence P bioavailability in aquatic ecosystems. Developing P fertilizer and cropping system management options with an understanding of soil P transformations helps maintain environmental sustainability.

Global solid waste generation is expected to double by 2050 from the present annual level of 2.01 metric ton. Traditional biowaste treatment methods, such as landfilling and incineration, cannot meet the need to deal with gigantic amounts of waste and reduce environmental harm. This review critically evaluates existing sustainable waste management strategies highlighting their role in transitioning to a "reuse and recovery" paradigm. Sustainable waste management refers to conserving resources and protecting human health, society, and the environment. In this context, this review examines the current advancements and potential trends in using widely available biowaste in novel applications to produce key biofuels (such as biogas and biodiesel) and resources such as corrosion inhibitors, asbestos-free brake pads, nutrient-rich functional foods, bio-cement, bio-based fertilizer, and biodegradable plastic. Among these, biowaste-to-energy conversion (e.g., biogas production) and biodegradable plastic synthesis emerge as particularly impactful strategies due to their scalability and potential to address both waste reduction and resource recovery goals. The strategic utilization of biowaste resources into novel products holds significant promise in mitigating sustainability problems, offering renewable alternatives that are biodegradable and free of harmful additives.

Maintaining yield goals while reducing nitrate-nitrogen (NO₃-N) leaching to groundwater is a challenge for potato (Solanum tuberosum) production in the Wisconsin Central Sands as well as across the United States. The objectives of this study were to quantify the effect of conventional and enhanced efficiency nitrogen (N) fertilizers on NO₃-N leaching, crop yield, and N uptake in potatoes. We compared five N treatments, which include a 0 N control and 280 kg ha^-1 as ammonium sulfate and ammonium nitrate (AS/AN), polymer-coated urea (PCU), urea with a urease inhibitor (Urea+UI), or urea with a UI and a nitrification inhibitor (Urea+UI+NI). The study occurred on grower fields during the 2009, 2010, and 2011 growing seasons, and NO₃-N leaching was measured with equilibrium tension lysimeters. PCU resulted in a reduction in NO₃-N leaching and an increase in yield compared to AS/AN in a year with large early-season rainfall; Urea+UI also reduced NO₃-N leaching in this year. In 2010, large plot-to-plot variation and 250 kg ha^-1 of additional N applied by the grower masked our ability to see differences among fertilized treatments. In 2011, a year with less intense rainfall events, no differences among treatments were observed. Collectively, these results show a potential benefit to PCU, but these benefits are only realized under specific seasonal weather conditions. Overall, the percentage of applied N lost to leaching during the growing season and removed in biomass was relatively low, suggesting substantial amounts of NO₃-N leaching outside of the growing season.

Phosphorus (P) loss from soils can contribute significantly toward P enrichment in water bodies, impairing water quality. Application of soil amendments is a viable strategy to decrease soluble P in surface soils. Since soluble P is reduced through different mechanisms that are amendment-specific, blended amendments could be a better approach than single amendment applications; however, very little information is available on blended amendment effects in reducing P loss from soils. We compared the effectiveness of gypsum (CaSO₄·2H₂O), Epsom salt (MgSO₄·7H₂O), and alum [Al₂(SO₄)₃·18H₂O] applied singly or blended in different ratios in reducing water-extractable P (WEP) and Mehlich-3 P of two soils (0- to 15-cm depth) with contrasting P status (Mehlich-3 P of 7.1 mg kg^-1 and 202 mg kg^-1) from the Red River Valley region in MB, Canada. Ten treatments used for the laboratory incubation study were unamended control, gypsum or Epsom salt at 2.5 or 5 Mg ha^-1, alum at 2.5 Mg ha^-1, and four blended treatments of gypsum: alum or Epsom salt: alum at 1:1 or 2:1. Treated soils were saturated and incubated for 2 weeks and analyzed for WEP (an indicator of risk of P loss) and Mehlich-3 P (plant-available P) concentrations. All amendments significantly reduced the WEP concentrations compared to control in both soils. The blended amendments, particularly gypsum-alum blends, performed better than unblended amendments in reducing the potential risk of P loss. Mehlich-3 P concentration was not influenced by amended treatments, suggesting no significant decrease in plant-available P with amendments in both soils.

Population growth in coastal areas increases nitrogen inputs to receiving waterways and degrades water quality. Wetland habitats, including floodplain forests and marshes, can be effective nitrogen sinks; however, little is known about the effects of chronic point source nutrient enrichment on sediment nitrogen removal in tidally influenced coastal systems. This study characterizes enrichment patterns in two tidal systems affected by wastewater treatment facility (WWTF) effluent and assesses the impact on habitat nitrogen removal via denitrification. We collected intact sediment cores from prevalent habitats in a tidal freshwater river (TFZ; swamp forest) and a tidal estuarine creek system (EST; salt marsh) upstream and downstream of a WWTF outfall, and quantified dissolved gas fluxes across the sediment-water interface during wet conditions in early summer and dry conditions in late summer. Data collected during two synoptic water quality monitoring campaigns complimented laboratory experiments to provide environmental context for biogeochemical processing. The two systems exhibited different enrichment patterns such that the river-dominated TFZ system was characterized by consistently elevated nitrate + nitrite concentrations downstream of the WWTF, whereas precipitation and tidal influence affected nutrient distributions in the EST creek. Downstream sediments in TFZ exhibit an apparent saturation response, while upstream rates may be limited by other factors, such as labile organic matter availability. In contrast, downstream sediments in EST denitrify at higher rates than upstream during wet conditions that may enhance transport of effluent. This work provides information on ecosystem functioning in human-influenced environments and can be of use in developing nature-based solutions, such as water treatment wetlands, for nitrogen removal.

The Eastern Corn Belt (ECB) node of the Long-Term Agroecosystem Research (LTAR) network is representative of row crop agricultural production systems in the poorly drained, humid regions of the US Midwest and a significant focus for addressing water quantity and quality concerns affecting Lake Erie and the Gulf of Mexico. The objectives of this paper were to (1) present relevant background information and collection methodology, (2) provide summary analyses of measured data, and (3) provide details for accessing the dataset and discuss potential database applications. The ECB-water quality (ECB-WQ) database is comprised of hydrology and water quality data from three privately owned farms in Northwest Ohio and Northeast Indiana and is available for download through the United States Department of Agriculture Ag Data Commons. The dataset includes information on site characteristics (drainage area and soil type), field management (fertilizer application, planting rate, and yield), and daily discharge and measured nutrient concentrations from surface and subsurface tile drainage outlets. Discharge and water quality vary widely across the ECB and are paramount to developing innovative management strategies that balance crop production goals with environmental targets. Discharge is generally greater from subsurface tile drainage compared to surface runoff. Phosphorus concentrations are typically greater in the surface runoff compared to tile drainage, while nitrogen concentrations are greater in subsurface tile drainage. The ECB-WQ database was developed to better facilitate understanding of water quantity and quality within this unique, systematic, artificially tile-drained region and is critical for understanding implications of field management practices, quantifying environmental and production processes, constraining hydrology/water quality models, and informing future water quality policies.

Agricultural researchers are increasingly encouraged to engage with stakeholders to improve the usefulness of their projects, but iterative research on the design and assessment of stakeholder engagement is scarce. The USDA Long-Term Agroecosystem Research (LTAR) Network recognizes the importance of effective engagement in increasing the utility of information and technologies for future agriculture. Diverse stakeholders and researchers at the Kellogg Biological Station (KBS) LTAR site co-designed the KBS LTAR Aspirational Cropping System Experiment, a process that provides a testing ground and interdisciplinary collaborations to develop theory-driven assessment protocols for continuous stakeholder engagement. Informed by prior work, we designed an assessment protocol that aims to measure participant preferences, experiences, and perceived benefits at various stages of this long-term project. Two online surveys were conducted in 2021 and 2022 among participants of LTAR engagement events at KBS, using a pre-post design, resulting in 125 total responses. Survey respondents had positive perceptions of the collaboratively designed research experiment. They had a strong expectation that the research would generate conservation and environmental advances while also informing policy and programs. Respondents also indicated a desire to network with other stakeholders. The research team noted the significant role of a long-term stakeholder engagement specialist in inviting participants from diverse backgrounds and creating an open and engaging experience. Overall, results highlight an interdisciplinary path of intentional and iterative engagement and evaluation to build a program that is adaptive and responsive to stakeholder needs.