Enhanced-efficiency nitrogen (N) fertilizer technologies have the potential to reduce N gas emissions, yet their effects on nitrous oxide (N2O) and ammonia (NH3) emissions are often inconsistent and context-dependent. The aim of this study was to quantify N2O and NH3 gas emissions using continuous photoacoustic infrared spectroscopy under varying N fertilizer rates, moisture regimes, and fertilizer sources in controlled incubations. Gas fluxes were measured every 48 min from fertilizer applied to bare soil in glasshouse (29 days) and laboratory (47 days) settings. Nitrous oxide emissions show N rate by moisture interactions, with emission factors ranging from 0.03% to 3.55%. Under moderate soil moisture (55% water-filled pore space [WFPS]), N2O emissions increased with N rate, whereas under high soil moisture (75% WFPS), the highest N rate (2500 kg N ha-1) resulted in unexpectedly low N2O emissions. In contrast, NH3 emissions were only observed at high N rates, regardless of moisture conditions, with emission factors around 1.1%-1.2%. Polymer-coated urea (PCU) and polymer-coated sulfur-coated urea (PCSCU) did not reduce cumulative N2O emissions relative to urea. Instead, PCU and PCSCU delayed N2O release, producing similar total emissions with altered temporal patterns. However, cumulative NH3 emissions were reduced by 81%-99% with the use of coated fertilizers. These findings suggest that while coated fertilizers help mitigate NH3 losses, their effectiveness in reducing overall N emissions is highly dependent upon environmental conditions and application methods.

Coastal development has led to a reframing of shoreline protection best management practices (BMPs), which use geotextiles for erosion control and shoreline stabilization. One risk of geotextile use in dynamic coastal environments is degradation into microplastics. This preliminary study quantified microplastic release from such degradation. Two common BMP geotextiles, black silt fence and green mesh geomat, were exposed to simulated estuarine conditions in mesocosms that included wave action as well as ambient ultraviolet radiation and temperatures. Water from the mesocosms was sampled, sieved, and analyzed through a combined approach of visual counting and laser direct infrared (LDIR) analysis. Visual counts revealed elevated synthetic particles in both treatments, with black particle concentrations 8.8x higher in the black silt fence treatment and green particle concentrations 5.1x higher in the green mesh geomat treatment. LDIR verification indicated elevated polypropylene concentrations from first exposure "wash-off" (5600 particles m[-2] day[-1] for the black silt fence and 20,000 particles m[-2] day[-1] year for the green mesh geomat). Shedding rates generally increased after the second sampling to a maximum rate of 140 and 230 particles m[-2] day[-1] for the green mesh geomat and black silt fence, respectively, at 48 days. Results indicate these geotextiles will release microplastics for far longer time scales than was monitored in this project, suggesting a need for a reassessment of current BMP materials and their management to better mitigate microplastic pollution in coastal environments.

Floodplain agroecosystems are particularly susceptible to sediment redistribution due to seasonal flooding, snowmelt, and agricultural activities. However, field-based evidence on the performance of narrow vegetative filter strips (VFS) under such dynamic hydrological conditions remains limited. This study evaluated the effectiveness of narrow VFS (2 and 4 m) in regulating sediment deposition within agricultural drainage ditches of the Lake Saint-Pierre floodplain, Québec, Canada, a cold-region agroecosystem characterized by recurrent spring flooding. From 2019 to 2023, sediment deposition dynamics were monitored across three floodplain sites using repeated total station surveys, complemented by UAV-based LiDAR measurements. Annual sediment deposition volumes were quantified and standardized by ditch length (m[3] m[-] [1]) to account for site-scale variability, and statistical analyses were used to assess VFS effects across widths and over time. Across sites, 4-m VFS consistently reduced sediment deposition by approximately 30% relative to control ditches without VFS (p < 0.10). In contrast, 2-m VFS exhibited highly site-dependent and statistically nonsignificant effects, reflecting interactions among VFS width, ditch morphology, and hydrological connectivity during flood and snowmelt periods. Differences in sediment deposition between growing and nongrowing seasons were modest, suggesting that sediment inputs are primarily controlled by episodic flood and snowmelt events rather than seasonal vegetation cover. Comparisons between LiDAR- and total station-derived ditch volumes showed strong agreement, with an average difference of approximately 10%. These results demonstrate that narrow VFS can contribute to sediment regulation in floodplain agricultural drainage networks, although their effectiveness is constrained by hydrological context and strip width.

Plastic mulch films are widely used in agriculture, often in combination with pesticide application. While biodegradable plastic mulch films (BDM) are designed for soil incorporation, their influence on pesticide fate remains poorly understood. We investigated the influence of BDM on the degradation kinetics of four widely used pesticides (boscalid, pyraclostrobin, fluopyram and pyraflufen-ethyl) in two agricultural soils under controlled conditions. Pesticides were applied at agronomically relevant doses either directly to soil or adsorbed onto a commercially available polybutylene adipate terephthalate-starch BDM prior to soil incorporation, and pesticides and their relevant metabolites were monitored for 112 days. Adsorption to BDM significantly slowed pesticide degradation for all compounds, increasing degradation half-lifes (DT50) by factors of 2-26 compared with direct soil application. While degradation pathways were not fundamentally altered, the presence of mulch delayed metabolite formation and prolonged pesticide persistence. Rapid degradation of pyraflufen-ethyl led to the accumulation of pyraflufen-ethyl metabolite E-3, a highly persistent multi-halogenated metabolite that remains analytically and regulatorily overlooked. BDM itself showed limited mass loss (12%) over the experimental period, suggesting that pesticide-plastic interactions can persist over environmentally relevant timescales. Overall, this study identifies plastic mulch residues as overlooked modifiers of pesticide persistence and metabolite accumulation in soil, suggesting that plastic-pesticide interactions warrant further consideration in environmental exposure and risk assessment frameworks.

Accurate quantification of deep percolation is fundamental for understanding vadose zone hydrology, groundwater recharge, and solute transport in agricultural landscapes. Many lysimeter designs impose fixed or passively generated suction that does not continuously respond to changes in the surrounding soil hydraulic environment, limiting the conditions under which representative drainage is collected. Automated equilibrium tension lysimeters (AETLs) aim to address this limitation by continuously adjusting lysimeter suction to match bulk soil matric potential. However, existing AETL systems are constrained by high power demands, limited sensor performance, and complex operation. This paper presents an updated AETL system that integrates contemporary hardware, solar-powered operation, and remote communication to improve system reliability and temporal resolution. Sixteen AETLs installed at 120-cm depth in silt loam soils in south-central Wisconsin were monitored during the 2025 growing season. Performance evaluation indicated that several systems were not fully equilibrated during early spring, suggesting drainage may have been under-collected. Despite this limitation, drainage occurred primarily during late winter and spring when soils approached saturation, whereas summer precipitation rarely produced drainage. Drainage varied substantially among lysimeters (∼1%-40% of cumulative precipitation), reflecting early-season operational variability and microtopographic controls on water redistribution, contextualized using topographic wetness index. An independent soil-water budget showed drainage from better performing lysimeters fell within the expected range, while drainage from the poorer performing lysimeters did not. The updated AETL system enables high-resolution monitoring of deep percolation in non-tile-drained agricultural systems, though performance remains constrained by the power and hydraulic-contact limitations documented here.