Direct Air Emission Measurements from Livestock Pastures Using an Unmanned Aerial Vehicle-Based Air Sampling System

Remote Sensing · 2025-09-03

Quantifying air emissions from livestock pastures remains challenging due to spatial variability and temporal fluctuations in emissions due to weather conditions. In this study we used a small unmanned aerial vehicle (sUAV) equipped with real-time sensors and an air sample collection system to directly measure carbon dioxide (CO2), methane (CH4), ammonia (NH3), nitrous oxide (N2O), nitrogen dioxide (NO2), hydrogen sulfide (H2S), total volatile organic compound (VOC), and particulate matter (PM1, PM2.5, PM10) emissions across two dairy pastures, two beef pastures, and one sheep pasture in Wisconsin. Emission rates were calculated using the Lagrangian mass balance model and validated against ground-level dynamic flux chamber (DFC) measurements. UAV-based CO2 concentrations showed a strong correlation with DFC measurements (R2 = 0.86, RMSE = 21.5 ppm, MBE = +9.7 ppm). Dairy 1 yielded the highest emissions for most compounds, with average emission rates of 0.50 ± 0.28 g m−2 day−1 head−1 for CO2, 8.48 ± 2.75 mg m−2 day−1 head−1 for CH4, and 0.20 ± 0.60 mg m−2 day−1 head−1 for NH3. The sheep pasture, on the other hand, had the lowest CH4 and NH3 emission rates, averaging 0.35 ± 0.22 mg m−2 day−1 head−1 and 0.02 ± 0.05 mg m−2 day−1 head−1, respectively. Rainfall events (≥ 5 mm within five days of sampling) significantly elevated N2O emissions (0.56 ± 0.40 vs. 0.13 ± 0.17 mg m−2 day−1 head−1). Particulate matter emissions were significantly affected by forage density. PM2.5 emission rates reached 1.25 × 10−4 g m−2 day−1 head−1 under low vegetative cover. It was concluded that emissions were affected by both animal species and the environmental conditions. The findings of this study provide a foundation for further development of emission inventories for pasture-based livestock production systems.

Soil preferential flow dynamics in the southern drylands of India—a watershed based approach

Frontiers in Water · 2025-01-07 · 1 citations

Preferential flow refers to the specific pathways through which water flows, including biopores, fractures, and macropores. Soil preferential flow has become increasingly important in the face of changing climates, erratic rainfall patterns, and for effective rainwater management. In semi-arid regions, watersheds serve as fundamental hydrologic units, providing a holistic perspective for the study of soil preferential flow. Given that limited research has been conducted on soil preferential flow in the dryland regions of southern India, the Hayathnagar watershed in Hyderabad was selected for this study. Land uses at different elevations were considered to systematically collect data on soil preferential flow, allowing for an analysis of how variations in elevation and land use influence flow dynamics across the landscape in the watershed. Brilliant blue tracer experiments were conducted at selected sites within the Hayathnagar watershed to assess soil preferential flow and investigate the subsurface movement of water across three land uses (cropped, fallow, and forest) under varying elevations. Vertical profile images were captured using a Canon EOS 1300D digital camera, producing high-resolution images (5184 × 3456 pixels). These digital images were then processed using ArcGIS 10.3 and ImageJ. The presence of preferential flow was clearly evident across all three different land uses and elevations within the watershed. The lower reach, with the least elevation, exhibited the highest dye coverage, correlating with greater uniform infiltration depth values. Furthermore, the middle reach displayed the maximum soil preferential flow, as indicated by the higher preferential flow fraction values, which were further justified by the preferential flow evaluation index. Heterogeneous matrix flow and fingering were observed both at the surface and sub-surface, along with macropore flow with low and mixed interactions. The findings and methodology of this study have significant implications for understanding preferential flow in diverse watersheds across the region. By enhancing our understanding of soil–water dynamics and flow patterns within the soil profile, this research contributes to the development of effective water management strategies in such areas.

Impact of long-term rice–rice monocropping on soil properties and organic carbon stocks in the NSLC command area: A case study from Telangana, India

Journal of the Indian Society of Soil Science · 2025-01-01

AbstractSoil organic carbon (SOC) is a crucial determinant of soil health and plays a vital role in climate change mitigation and sustainable agriculture, particularly in semiarid agro-ecoregions. This study evaluates the long-term impact of rice monocropping on soil properties and SOC dynamics in the Nagarjuna Sagar Left Canal (NSLC) command area of Telangana, India—an agriculturally transformed landscape that shifted from traditional rainfed cropping to canal-irrigated rice monoculture post-1967. The research aimed to characterize and classify the soils under continuous rice cultivation and to assess SOC stocks in relation to changing land use practices. A comprehensive methodology was adopted involving detailed field surveys, soil profile studies, and laboratory analyses. Four representative soil series were studied to determine physical and chemical characteristics including soil texture, pH, electrical conductivity, cation exchange capacity, and SOC content. SOC stock was estimated using standard bulk density and carbon concentration data across depth intervals. The findings revealed that long-term rice monoculture under canal irrigation significantly altered soil properties, leading to moderate alkalinity and varied SOC distribution. Notably, improved SOC stocks were observed in soils with practices such as partial residue burning, puddling, and seasonal water retention. The study highlights that despite potential SOC depletion due to intensive cultivation; appropriate management interventions can enhance carbon sequestration. The results support global initiatives like the “4 per 1000” strategy, underlining the potential of sustainable rice-based systems in enhancing SOC in hot semiarid regions. Continued research and adoption of climate-smart soil management practices are essential for improving soil health and resilience in similar agro-ecological zones.

Shedding light on the polymer’s identity: Microplastic detection and identification through nile red staining and multispectral imaging (FIMAP)

Journal of environmental chemical engineering · 2025-07-08 · 6 citations

The widespread distribution of microplastics (MPs) in the environment presents significant challenges for their detection and identification. Fluorescence imaging has emerged as a promising technique for enhancing the detectability of plastic particles and enabling accurate classification based on fluorescence behavior. However, conventional image segmentation techniques for fluorescent particles face several limitations, including poor signal-to-noise ratio, inconsistent illumination, particle thresholding difficulties, and false positives from natural organic matter (NOM). To overcome these challenges, this study introduces the Fluorescence Imaging for Microplastic Analysis Platform (FIMAP), a retrofitted multispectral camera equipped with four distinct optical filters and excited at five different wavelengths. We demonstrate that FIMAP enables comprehensive characterization of the fluorescence behavior of ten Nile Red-stained MPs (HDPE, LDPE, PP, PS, EPS, ABS, PVC, PC, PET, PA) while effectively excluding NOM. This is achieved through K-means clustering for robust particle segmentation (Intersection over Union = 87.7%) and a 20-dimensional color coordinate multivariate nearest neighbor approach for MP classification (>3.14 mm), yielding a precision of 90%, accuracy of 90%, recall of 100%, and an F1 score of 94.7%. Among the ten MPs, only PS was occasionally misclassified as its expanded form (EPS). For smaller MPs (35–104 μm), classification accuracy declined, likely due to reduced fluorescent stain sorption, fewer detectable pixels, and camera instability. However, integrating FIMAP with higher-magnification instruments, such as a microscope, may enhance MP identification accuracy. In summary, FIMAP introduces an automated, high-throughput framework for the comprehensive detection and classification of MPs across large environmental sample volumes. • FIMAP enables automated detection and classification of Nile Red-stained MPs. • K-means clustering improves segmentation, reducing false positives from NOM. • Multispectral imaging (5 excitations, 4 filters) reveals distinct MP fluorescence patterns. • Nearest neighbor search achieves 90% precision and classification accuracy for 10 MPs. • FIMAP provides a scalable solution for high-throughput environmental MP analysis.

Investigating the effect of animal manure on colloidal-facilitated phosphorus transport

Geoderma · 2025-02-24 · 5 citations

• The effect of manure type on P losses in various forms in leachate was quantified. • Preferential flow was observed in the soil columns. • Manure type affected the concentration of various forms of P in leachate. • Colloidal-facilitated P loss can be significant. Preferential flow via soil macropores can enhance phosphorus (P) loss in leachate. The application of animal manure can further exacerbate P losses in leachate in various forms. Limited work has been done to quantify colloidal-facilitated-P loss in leachate as a function of manure type. Therefore, the goal of this study was to determine the impact of three manure types, namely, poultry litter, swine lagoon effluent, and dairy manure, on P leaching in various forms using column-based rainfall simulation experiments. Intact-undisturbed soil columns were collected from a pasture field located in Alabama, USA. The overall experimental design included four treatments with two replications each (poultry litter (solid) at rate 1, poultry litter (solid) at rate 2, dairy manure (semi-solid), and swine lagoon effluent (liquid) and unamended control). The bromide breakthrough curves showed evidence of preferential flow. The flow-weighted mean total P concentrations for treatment columns ranged from 5.4 to 6 mg L −1 , 6.22 to 12.18 mg L −1 , 0.95 to 1.42 mg L −1 , and 0.29 to 1.1 mg L −1 for columns treated with solid poultry litter at rate 1, solid poultry litter at rate 2, swine lagoon effluent, and dairy manure, respectively. Colloidal P accounted for 5 to 49 % of the total P leaching from the treatment columns. Therefore, the results of this study show that colloidal-facilitated migration of P can be significant and should be considered when elucidating P transport in agricultural systems fertilized with animal manure.

BioWin Modeling of CalPrex Phosphorus Recovery from Wastewater Predicts Substantial Nuisance Struvite Reduction

Environments · 2024-02-29 · 7 citations

The wastewater treatment industry could benefit from new technologies for the removal and recovery of phosphorus (P). The CalPrex precipitation reactor has the potential to recover P in a readily land-applicable form by treating organic acid digestate with calcium hydroxide to produce brushite. Using data from a pilot-scale reactor at the local Nine Springs Wastewater Treatment Plant in Madison, WI, we modified the plant’s BioWin configuration using BioWin 6.2 to model the CalPrex technology and estimate performance under a variety of conditions. We produced dose/response curves for a range of possible lime dosages to estimate the impact of reagent dosage on the quantity and composition of precipitate produced by the CalPrex reactor and characterize the effects on downstream anaerobic digester performance. CalPrex was found to capture 46% of the plant’s influent P, reducing nuisance struvite precipitates by 57% and biosolid sludge production by 14%. The CalPrex module was also tested in two predesigned plant configurations in the BioWin cabinet with the intention of testing applicability to other configurations and searching for the impacts of CalPrex on treatment train performance. This is the first work simulating a full-scale implementation of CalPrex and the first to model interactions of CalPrex with other treatment processes.

BioWin Modeling Comparisons of Municipal Wastewater Phosphorus Recovery between Brushite and Struvite

ACS ES&T Water · 2024-10-01 · 2 citations

New technologies hold promise for advancing wastewater treatment by enhancing phosphorus (P) removal and recovery. The CalPrex precipitation reactor treats acidogenic digest with lime to precipitate brushite, recovering P in a form suitable for land application while reducing the buildup of nuisance struvite. To assess CalPrex performance in different scenarios, including its interaction with existing Ostara (struvite) reactor installations, we adapted a BioWin configuration of a municipal wastewater treatment plant hosting both a pilot-scale CalPrex reactor and a full-scale Ostara reactor. Our modeling work aimed to estimate the impact of reagent dosage on plantwide P recovery. When used alongside the Ostara process, CalPrex captured 36% of influent P, resulting in a 48% reduction in struvite precipitates in the anaerobic digester and a 12% decrease in the overall sludge production. As the sole P removal process, CalPrex was predicted to capture 41% of influent P, leading to a 33% decrease in anaerobic struvite precipitates and an 8% reduction in total sludge production compared with the current configuration with the Ostara reactor. This study represents the first attempt to model CalPrex interactions with other wastewater treatment technologies and can inform wastewater operators seeking to expand their P management systems.

Preferential flow of phosphorus and nitrogen under steady‐state saturated conditions

Vadose Zone Journal · 2024-04-21 · 11 citations

Abstract Repeated broiler litter application on agricultural lands can cause nutrient enrichment of subsurface effluent, especially with the existence of preferential flow through soil macropores. Previous studies quantifying soil macropores have not attempted to establish a connection of soil macropore characteristics with the subsurface nutrient (nitrogen [N] and phosphorus [P]) losses, across different topographical locations in the field. This study investigated the effect of broiler litter application and preferential flow on subsurface nutrient transport (N and P) at different topographical positions (upslope, midslope, and downslope) in a no‐till pasture field located in Alabama, USA. Twelve intact soil columns (150 mm id and 500 mm length) were used, and the nutrient leaching measurements from laboratory experiments were linked to soil macropore characteristics quantified using X‐ray computed tomography image analysis and solute transport modeling. Treatments included surface broadcast broiler litter (5 Mg ha −1 , on dry basis) and unamended control. Leachates were analyzed for dissolved reactive P (DRP), total P (TP), and nitrate + nitrite‐N (NO 3 − + NO 2 − –N). The bromide breakthrough curves provided evidence of preferential flow in all columns. Litter application significantly increased leachate P concentrations, and average TP and DRP concentrations were significantly higher in the leachate from upslope columns compared to those at downslope location. The NO 3 − –N concentrations in leachate exceeded the US EPA drinking water standard of 10 mg L −1 in all the treatment columns. The highest flow‐weighted mean concentrations of TP and DRP, at 2.7 and 2.5 mg L −1 , respectively, were recorded in the upslope columns. Soil physicochemical properties and nutrient leaching losses varied substantially across topographical positions, indicating a need for variable litter application rates to reduce P build‐up and subsequent leaching in vulnerable locations within the field. The relevance of the effect of topographic position on nutrient leaching found in this study should be further tested by investigating a wider range of slopes and soil types in pastures.

Improving BioWin Modeling of Phosphorus Solubilization in Acid-Phase Digesters

Environments · 2024-02-03 · 3 citations

BioWin 6.0 does not accurately predict phosphorus (P) speciation in acidogenic anaerobic digesters under default kinetics characterization and parameterization. The accurate modeling of acid-phase digestion is needed to predict the performance of novel nutrient recovery technologies that act on these digester effluents. The main thrust of this work was to identify and correct the causes of inaccurate P partitioning and precipitation within BioWin models of acid-phase digestion reactors. A BioWin configuration including an organic acid digester was parameterized and recalibrated based on the known traits of acid-phase digestion and then validated against a full-scale digester in a municipal wastewater treatment plant. This digester, with pH 5.14 and 61–74% solubilized P, was predicted by BioWin default parameters to have only 27% soluble P and a net formation of P precipitates. Corrections to the polyphosphate-accumulating organism decay, endogenous product decay, hydrolysis rate, and brushite behavior resulted in 67% solubilization with no precipitate formation. Cabinet configurations showed similar behavior when modified to include an acid-phase digester under default parameters, but predictions were similarly amended by our parameter changes. This improved modeling technique should allow operators to effectively characterize acid digesters for their own treatment trains and allow engineers to predict the performance of novel nutrient recovery technologies acting on acidogenic digest.

Design and parameter optimization of microwave sensor for fat content detection in milk

AIP conference proceedings · 2024-01-01 · 6 citations