Journal of environmental quality最新文献

The sustainable intensification of crop production provides more output with similar or fewer inputs, and therefore helps to produce food, feed, fiber, and fuel more efficiently. While short-stature maize (Zea mays L.) hybrids have been shown to be more climate resilient, with reductions in yield-scaled greenhouse gas production due to reduced crop damage during wind events, other aspects of the climate impact of short-stature maize remain to be quantified. Here we will discuss the use of the greenhouse gases, regulated emissions, and energy use in transportation life cycle assessment model and data inputs from 199 total site-years of grain yield data, 11 site-years of root data, and 10 site-years of stover nitrogen (N) data to determine the carbon (C) footprint of short-stature maize systems for grain production. Short-stature maize hybrids had comparable grain yields to tall comparators under standard management; however, leveraging benefits of the systems, such as in-season access, and higher plant populations improved the yield and efficiency of production. Root volume was increased by 39% for short-stature hybrids compared to tall hybrids. Across a range of agronomic system scenarios, that consider changes in plant density and improved in-season access for split-rate N application, and soil C dynamics, there is a range of greenhouse gas savings of 0.09–0.78 t CO₂e ha⁻¹ year⁻¹ for short-stature maize systems due to improvements in grain yield without increased inputs, reduction in stover N and subsequent N₂O emissions, and increased root dry matter incorporation into soil organic carbon.

Elovaara, S., Zhao, L., Asmala, E., Kaartokallio, H., & Thomas, D. N. (2025). Changes in riverine dissolved organic matter caused by gypsum-induced flocculation. Journal of Environmental Quality, 54, 369–381. https://doi.org/10.1002/jeq2.70001

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Efficient and sustainable nitrogen (N) management is critical for addressing the dual challenges of maximizing productivity and mitigating environmental impacts in short-cycle crops like lettuce (Lactuca sativa). This study evaluates the agronomic performance and nutrient dynamics of eight N fertilizer treatments, including mechanochemically synthesized urea-based cocrystals, conventional urea, and mechanochemically synthesized carbonate salts alongside accessible digital phenotyping methods for a greenhouse-grown romaine lettuce system. Plant growth, biomass production, chlorophyll content, and soil N residues were measured in conjunction with digital image-derived spectral indices from traditional photography. Engineered sulfate cocrystals (zinc sulfate urea and copper sulfate urea) performed comparable to or better than urea in promoting growth and N use efficiency, while engineered carbonates displayed moderate responses, likely due to slower N release. Traditional image-based indices such as normalized green-red difference index, hue angle, and green color distance metric, as well as more unique visual calculations, effectively captured plant nutritional status and correlated with chlorophyll levels. Principal component and cluster analyses further distinguished treatment performance based on growth and color metrics. These findings demonstrate the potential of combining novel N delivery systems with low-cost phenotyping technologies to transform sustainable nutrient management practices across diverse crop systems.

System fertilization enhances logistics and phosphorus (P) use efficiency, but its effects in high P-export systems, particularly regarding fertilization timing, placement, and distribution, remain unclear. This study evaluated P fertilization timing (90, 45, and 0 days before winter crop sowing [DBS]), placement (banded vs. broadcast), and spatial distribution (17 × 5 vs. 40 × 10 cm) in subtropical Oxisols with medium and high soil-test P. Over 4 years, we assessed crop yields, partial phosphorus balance (PPB), and Mehlich-1 available soil P (0–10 and 10–20 cm) under rotations of corn (Zea mays L.), soybean (Glycine max L.), and winter crops including black oat (Avena strigosa Schreb.), barley (Hordeum vulgare L.), vetch (Vicia sativa L.), and fodder radish (Raphanus sativus L.). Despite pronounced P stratification, yields and PPB were generally unaffected. In medium P soil, the 40 × 10 cm spacing increased P in the 10–20 cm layer to 61% of the critical value after 4 years. In high P soil, P application at winter sowing raised subsurface P to 4.5 mg dm⁻³. Soybean yield (5.2 Mg ha⁻¹) and PPB (73%) peaked with 90 DBS banded fertilization. Anticipating fertilization by 90 days with 17 × 5 cm spacing improved soybean yield by 20% and PPB by 10% due to better surface P distribution. The 0–10 cm layer remained P-rich and sufficient for grain yield. However, the benefits of 90 DBS were limited to two seasons. Long-term studies are needed to refine system fertilization strategies in high-output grain systems.

Excess of nitrogen (N) and phosphorus (P) increases the eutrophy level and can produce severe algal blooms in lakes and ponds. We introduce tycho-filtration based on self-settling algae aggregates, a biotechnology to extract excess of N and P from hypertrophic waters. This technical note has the following four scopes: (i) explaining the operating principle of tycho-reactors, (ii) drawing attention to parameters that may influence performance, (iii) identifying strategies for containing nuisance organisms in tycho-reactors, and (iv) discussing potential applications of this technology. A proof of concept 3 m² tycho-reactor with 880 liters per hour daily-peak flow-through rate yielded ≤120.4 g dry weight (DW) algae biomass m⁻² day⁻¹. This biomass consisted of 55% desmid Chlorophyceae and 44.8% diatoms vol:vol, carrying ≈4.16% N and ≈0.43% P per DW. Biological interferences requiring specific management include surface-attached filamentous algae, toxin-producing cyanobacteria, and the algae-eating bladder snail (Physella acuta). Advantages of tycho-filtration are predicted to come from photosynthesis being reliant on solar light, low cost of algae harvesting, potential for automation, and suitability for solar-based water flow. Potential applications of this technology include preventing severe algal blooms in small lakes, control of N in recirculated aquaculture, and detrophication of liquid effluents from aquafarms that threaten downstream ecosystems.

With the search for water security, the reuse of water in irrigation becomes interesting and inevitable. Given the complexity of soil–solute interactions, the use of simplified artificial solutions represents an innovative approach, as it facilitates understanding these interactions while posing no risk to human health or the environment. However, the more complex and inferior the quality of the water, the greater the environmental contamination risk. The objective of this study was to investigate ion retention in three tropical soils (Oxisol, Inceptisol, and Entisol Quartzipsamment) by applying treated domestic wastewater (TWW) and artificial wastewater, both with the same concentrations of Na⁺, K⁺, Ca²⁺, and Mg²⁺ as the TWW. Physical, chemical, and mineralogical properties of the soil were determined. Multivariate analysis was performed to elucidate the relationships between the solutes’ transport parameters, the soils’ mineralogy and texture, and the variation in their chemical characteristics resulting from wastewater application. Oxisol and Entisol Quartzipsamment contributed to principal component 1. The second principal component had a negative contribution from Inceptisol. Oxisol and Entisol Quartzipsamment showed the longest delays of ion transport relative to the wetting front. Inceptisol had the lowest retardation factors and the lowest affinity for ions. For the TWW on Oxisol, Na⁺ was the first ion to reach a relative concentration equal to 1, at an average pore volume of 4.3; however, the last pore volume collected for Ca²⁺ was 12.3, with a relative concentration of 0.6, showing that sodium in TWW is a point of attention, as observed by the low affinity with soils.

In this study, changes in P runoff losses from three field-scale small watersheds in the Northern Great Plains region (Manitoba, Canada) under organic management were evaluated over a 7-year period (2017–2023). A perennial forage crop was grown through this time period, either with biennial addition of a slow-release fertilizer to maintain soil fertility (struvite, 4 site-years) or without P amendment (drawdown, 8 site-years). Annually measured soil P (Olsen P) strongly correlated with mass balance of P added as struvite or removed by crops and surface runoff. As a result, P limitation of forage yield was observed in the later years of the drawdown treatment. P loads and flow-weighted mean concentrations (FWMCs) measured in snowmelt runoff after struvite application were compared to predicted values using published regional models developed with 82 site-years of data from field-scale small watersheds, with Olsen P, water yield, and percent surface cover as predictors. To evaluate response to struvite over a wider range of conditions, P runoff was measured in two additional watersheds under conventional annual grain production following struvite application (2 site-years). Higher risk of P loss was observed with higher Olsen P. However, following struvite applications, the risk of P loss to snowmelt was consistently lower than predicted (between −0.13 and −0.85 mg L⁻¹ for FWMC of total dissolved P) suggesting that the solubility of struvite in runoff water may be lower than for other forms of soil P also extractable as Olsen P.

Effective management of surface water quality requires a thorough knowledge of the characteristics and contributions of various pollution sources. While stable isotope methods are highly effective for nitrate source tracking, their high cost and operational complexity constrain their routine use in watershed management. This study examined and contrasted the dual stable isotopes (δ¹⁵N-NO₃⁻, δ¹⁸O-NO₃⁻, and the MixSIAR [Bayesian mixing models in R] model) with fluorescence analysis (EEM-PARAFAC [fluorescence excitation–emission matrices coupled with parallel factor analysis]) to trace the origins of nitrate and dissolved organic matter in the Lujiang River, a coastal agriculture-dominated river in southeastern China. Additionally, the feasibility of EEM-PARAFAC as a low-cost complementary tool for nitrate source tracking was assessed. The MixSIAR model identified soil nitrogen (41.0%–49.7%) and fertilizers (29.5%–37.9%) as dominant nitrate sources, pointing to significant nonpoint source pollution. With increasing urbanization, point source pollution from manure and sewage increased from upstream (11.5%) to midstream (13.1%) and downstream (15.3%). EEM-PARAFAC analysis supported these findings, with humic-like components (C1 + C2: 59.31%, 56.85%, and 46.98% in upstream, midstream, and downstream, respectively) showing a strong correlation (r = 0.97) with soil nitrogen contributions identified by MixSIAR. Protein-like components (C5, r = 0.93; C6, r = 0.97) were associated with fertilizers and sewage, respectively, consistent with their increasing downstream contributions, validating EEM-PARAFAC's capacity for cost-effective source discrimination. This study demonstrates that integrating the two methods enhances the understanding of pollutant source dynamics in complex river systems, offering valuable insights for improving water quality and watershed management.

Microplastics are a ubiquitous contaminant, and their movement through freshwater systems is an understudied part of the “plastic cycle.” We collected monthly surface water samples from 16 sites in an agriculturally dominated watershed, the Flint River, in southwestern Georgia to assess spatial and temporal variation in the composition and concentration of microplastics in a river system. The samples were sieved, digested in H₂O₂, and vacuum filtered onto filters for microplastic counting and morphological classification. Generalized linear models were built to investigate relationships among plastic concentration and morphology, land use variables, discharge, and physiochemical properties. All sites had detectable concentrations of microplastics, and the mean concentration (No./L ± SD) was 1.64 ± 2.17. Soluble reactive phosphorus was our strongest predictor of microplastic concentration, with measures of suspended particles also significantly explaining microplastic concentration. This research builds upon the findings of others to suggest that plastic may behave similarly to other particles. This work also documents that microplastics can be commonly found in agriculturally dominated rural watersheds with low human population densities.

The use of winter cover crops and conservation tillage are agricultural practices promoted to reduce nutrient and sediment loss from cropland, improve soil health, increase infiltration, and support farm nutrient cycling and ecosystem services. However, environmental performance of these practices is variable in the working farm landscape. The Lower Chesapeake Bay research project within the USDA Long-Term Agroecosystem Research (LTAR) network has collaboratively developed satellite remote sensing algorithms to measure the performance and phenology of winter cover crops (aboveground biomass, nitrogen content, fractional cover, and emergence and termination dates) using no-cost Harmonized Landsat and Sentinel-2 multispectral satellite imagery. This research supports annual operational assessment of >28,000 fields per year in four states. Results document the impacts of agronomic management on conservation outcomes, support adaptive management of incentive payment structures, and can reduce the workload for conservation district staff by remotely verifying cover crop management. Additionally, super-spectral satellite applications have been developed to accurately map crop residue cover by measuring lignocellulose absorption in shortwave infrared wavelengths, producing a 7-year time series of tillage intensity maps for the Delmarva Peninsula. These remote sensing products can be used in decision support and modeling to estimate changes in nutrient, sediment, and carbon cycling resulting from conservation practice implementation in the working farm landscape. This manuscript provides an overview of remote sensing research findings and applications associated with the USDA LTAR and Conservation Effects Assessment Projects (CEAP), documenting a variety of previously published outcomes with update and expansion of techniques using additional unpublished data and analyses as appropriate.