Niroj Aryal

Predicting water quantity and quality from agricultural watersheds is critical for effective management of agroecosystems. The ArcGIS-based Agricultural Policy Environmental eXtender (ArcAPEX) model (version 1501) was employed to simulate streamflow, sediment, and nutrient yield in an agricultural watershed in northeastern Arkansas, and to evaluate scenario-based conservation practices. The ArcAPEX model was set up using topographical, soil, agronomical, and meteorological data. Measured daily data used for model calibration and validation included streamflow and sediment and nutrient yields derived from analysis of in-stream water samples collected from the Little River Ditches watershed in Northeastern Arkansas from 2015 to 2022. Sensitivity analysis, model calibration, and validation were conducted using the APEX auto-calibration and uncertainty estimator. The simulated streamflow and sediment, total phosphorus (TP), and total nitrogen (TN) yields were within the model evaluation criteria with higher reliability. The average annual streamflow and sediment, TP, and TN yields measured from the watershed were 667 mm, 3.39 tons/ha, 4.69 kg/ha, and 5.4 kg/ha and those from the ArcAPEX model simulations were 628 mm, 3.96 ton/ha, 5.41 kg/ha, and 5.69 kg/ha, respectively, during the study period. The scenario-based ArcAPEX model demonstrated that the combination of cover crops and filter strips reduced the runoff, sediment, and nutrient yields most effectively. Implementing cover crops and filter strips across 30% of the watershed reduced sediment yield by 26%, more than any other pollutant. This study validated ArcAPEX as an effective tool for simulating surface runoff and sediment and nutrient yields in agricultural watersheds and predicting the impact of conservation practices, demonstrating its value for complex agroecosystem management.

Simple, one‐pot, and low‐cost fabricated Mg(OH) ₂ nanoflakes, synthesized at room temperature, exhibited enhanced properties necessary for phosphate ion adsorption from solutions. Scanning electron microscopy and transmission electron microscopy showed flake‐like nanoparticles that were highly segregated, offering high surface area and active sites. Other characterization techniques, such as energy‐dispersive X‐ray analysis, X‐ray diffraction, and X‐ray photoelectron spectroscopy, contributed to the understanding of the chemical composition of the materials. The investigation of zeta potential revealed the surface charge of the nanoflakes before and after adsorption, supporting the adsorption mechanism of phosphate. Results from the ion adsorption experiment using ion chromatography confirmed that our fabricated material performed well in the phosphate adsorption test.

Burkina Faso faces chronic food insecurity because of adverse agroclimatic conditions and significant soil degradation. Mulching, the practice of applying organic or synthetic materials to the soil surface, offers a promising avenue for enhancing agricultural production in this challenging agroecological setting. This study utilized the Sustainable Intensification Assessment Framework (SIAF) to evaluate the ecological, economic, and social impacts of mulching on vegetable production in Burkina Faso. Experimental and survey data collected from Sonsongona village in Bobo-Dioulasso were used to compare the production of mulched and non-mulched vegetables (tomato, cabbage, and onion) across the five SIAF domains. A calibrated AquaCrop crop model was also applied with 30-year historical weather data to simulate mulched and non-mulched cabbages for the study site. Our results reveal that mulching conserves soil moisture, suppresses weed growth, and enhances soil fertility, contributing to enhanced vegetable production and long-term sustainability. Economically, adopting mulching positively influences vegetable yields, reduces labor requirements, and increases income for smallholder farmers. These mulching benefits lead to community empowerment, particularly among women farmers. Our findings highlight the multifaceted benefits of mulching, suggesting that it holds promise for increasing agricultural productivity and improving economic stability, ecological sustainability, and social well-being in Burkina Faso. These insights contribute to developing context-specific strategies for sustainable intensification, with applicability across similar agroecological contexts in sub-Saharan Africa and beyond.

Contribution: This article discusses a research–practice partnership (RPP) where instructors from six undergraduate courses in three universities developed data science modules tailored to the needs of their respective disciplines, academic levels, and pedagogies. Background: STEM disciplines at universities are incorporating data science topics to meet employer demands for data science-savvy graduates. Integrating these topics into regular course materials can benefit students and instructors. However, instructors encounter challenges in integrating data science instruction into their course schedules. Research Questions: How did instructors from multiple engineering and science disciplines working in an RPP integrate data science into their undergraduate courses? Methodology: A multiple case study approach, with each course as a unit of analysis, was used to identify data science topics and integration approaches. Findings: Instructors designed their modules to meet specific course needs, utilizing them as primary or supplementary learning tools based on their course structure and pedagogy. They selected a subset of discipline-agnostic data science topics, such as generating and interpreting visualizations and conducting basic statistical analyses. Although instructors faced challenges due to varying data science skills of their students, they valued the control they had in integrating data science content into their courses. They were uncertain about whether the modules could be adopted for use by other instructors, specifically by those outside of their discipline, but they all believed the approach for developing and integrating data science could be adapted to student needs in different situations.

Highlights Winter cover crops and growing season filter strips were implemented without sacrificing significant land and achieved positive results. Cover crops reduced runoff depth, peak flow rate, sediment, TP, and TN load by 30%, 49%, 43%, 4%, and 7%, respectively. Filter strips reduced runoff depth, peak flow rate, sediment, TP, and TN load by 36%, 49%, 56%, 15%, and 21%, respectively. Abstract. Effective use of conservation practices in agricultural fields can reduce sediment and other pollutant loads entering waterways. In this study, we evaluated the effectiveness of using cover crops and filter strips on sediment and nutrient loss at the edge of paired, 7.83 ha (19.35 ac), commercial cotton fields in the Lower Mississippi River Basin (LMRB) in northeastern Arkansas. Cover crops included winter wheat, black oat, and ryegrass seeded in the winter fallow period, while filter strips included a grassy turn row at the field border and switchgrass transplanted around the drainage pipe at the edge of the treatment field. The field border of the control field was generally free from vegetation. A monitoring system measured discharge and collected composite water samples from rainfall and irrigation runoff events. Water samples were analyzed for phosphate (PO₄-P), total phosphorus (TP), nitrate (NO₃-N), ammonium (NH₄-N), total nitrogen (TN), and suspended sediment concentrations. Data were collected from 2015 to 2020. Baseline data were collected when both fields had similar conservation practices (i.e., no cover crops in 2015 and no filter strips in 2015 and 2016). A comparison of 66 common runoff events between the control and cover crop treatment fields during the non-growing season indicated that the median peak flow and sediment loads were significantly reduced (p < 0.05), with an average reduction of 49% and 43%, respectively. Similarly, a comparison of 55 common runoff events between the control and filter strips treatment fields during the growing season found that the filter strips reduced significantly with average runoff by 36%, peak flow by 49%, and sediment loads by 56% (p < 0.05). Nutrient load reductions by the cover crop and filter strip treatments were not significantly different than by the control (p > 0.05). However, mean PO₄-P, TP, NO₃-N, NO₂-N, NH₄-N, and TN loads in the cover crop treatment field were lower than in the control field by 21%, 4%, 9%, 4%, 17%, and 7%, respectively. Similarly, mean PO₄-P, TP, NO₃-N, NH₄-N, and TN loads in the filter strip treatment field were lower than in the control field by 23%, 15%, 11%, 42%, and 21%, respectively. The results demonstrated runoff depth, peak flow rate, nutrients, and sediment load reductions following the implementation of cover crops and filter strips at the commercial field scale. Keywords: Agricultural conservation practices, BMPs, Cotton, Cover crop, Edge-of-field monitoring, Filter strips, Switch grass.

Phytoremediation is used to treat wastewater, wherein plants, microorganisms, and soil work together to remediate pollutants. We evaluated the plant processes that can affect metal mobilization during phytoremediation. The experimental columns were filled with silica sand and soil mixture spiked with redox-sensitive metal(loid)s—arsenic, manganese, and iron, and fitted with an ORP probe and oxygen sensors. Three columns were planted with poplars and three others were no-plant controls. Carbon-rich, synthetic food-processing wastewater was applied at 15.4 mm/day to the columns. Leachate water was analyzed every other week for water quality. Both soil and plant tissue samples were analyzed for metal concentrations, and soils were analyzed for microbial populations. Both treatments reduced 65–70% carbon. ORP ranged from −321 mV to 916 mV and affected metal mobilization. Oxic conditions in planted treatments yielded high ORP, oxygen concentration, and nitrates. Microbial communities were enhanced in both treatments, but the planted columns had more microbial abundance and evenness. Plants successfully accumulated metals in roots from soil with an accumulation factor of up to 40 for some metals and translocated to shoots from roots with a translocation factor of 10.62. The crop coefficient was 1.88, indicating accelerated loss of water in planted columns compared to control columns. The results demonstrated the benefits of plants in creating more oxic conditions, removing more wastewater from the rhizosphere, accumulating and translocating metals in the biomass, and enhancing rhizodegradation of pollutants by microbial population enhancement. Knowledge of the soil–plant–microbial processes is useful in designing engineered phytoremediation systems.

Constructed wetland (CW) is a popular sustainable best management practice for treating different wastewaters. While there are many articles on the removal of pollutants from different wastewaters, a comprehensive and critical review on the removal of pollutants other than nutrients that occur in agricultural field runoff and wastewater from animal facilities, including pesticides, insecticides, veterinary medicine, and antimicrobial-resistant genes are currently unavailable. Consequently, this paper summarized recent findings on the occurrence of such pollutants in the agricultural runoff water, their removal by different wetlands (surface flow, subsurface horizontal flow, subsurface vertical flow, and hybrid), and removal mechanisms, and analyzed the factors that affect the removal. The information is then used to highlight the current research gaps and needs for resilient and sustainable treatment systems. Factors, including contaminant property, aeration, type, and design of CWs, hydraulic parameters, substrate medium, and vegetation, impact the removal performance of the CWs. Hydraulic loading of 10–30 cm/d and hydraulic retention of 6–8 days were found to be optimal for the removal of agricultural pollutants from wetlands. The pollutants in agricultural wastewater, excluding nutrients and sediment, and their treatment utilizing different nature-based solutions, such as wetlands, are understudied, implying the need for more of such studies. This study reinforced the notion that wetlands are effective for treating agricultural wastewater (removal > 90%) but several research questions remain unanswered. More long-term research in the actual field utilizing environmentally relevant concentrations to seek actual impacts of weather, plants, substrates, hydrology, and other design parameters, such as aeration and layout of wetland cells on the removal of pollutants, are needed.