Combining Environmental Monitoring and Remote Sensing Technologies to Evaluate Cropping System Nitrogen Dynamics at the Field-Scale

Nitrogen (N) losses from cropping systems in the U.S. Midwest represent a major environmental and economic concern, negatively impacting water and air quality. While considerable research has investigated processes and controls of N losses in this region, significant knowledge gaps still exist, particularly related to the temporal and spatial variability of crop N uptake and environmental losses at the field-scale. The objectives of this study were (i) to describe the unique application of environmental monitoring and remote sensing technologies to quantify and evaluate relationships between artificial subsurface drainage nitrate (NO3-N) losses, soil nitrous oxide (N2O) emissions, soil N concentrations, corn (Zea mays L.) yield, and remote sensing vegetation indices, and (ii) to discuss the benefits and limitations of using recent developments in technology to monitor cropping system N dynamics at field-scale. Preliminary results showed important insights regarding temporal (when N losses primarily occurred) and spatial (measurement footprint) considerations when trying to link N2O and NO3-N leaching losses within a single study to assess relationship between crop productivity and environmental N losses. Remote sensing vegetation indices were significantly correlated with N2O emissions, indicating that new technologies (e.g., unmanned aerial vehicle platform) could represent an integrative tool for linking sustainability outcomes with improved agronomic efficiencies, with lower vegetation index values associated with poor crop performance and higher N2O emissions. However, the potential for unmanned aerial vehicle to evaluate water quality appears much more limited because NO3-N losses happened prior to early-season crop growth and image collection. Building on this work, we encourage future research to test the usefulness of remote sensing technologies for monitoring environmental quality, with the goal of providing timely and accurate information to enhance the efficiency and sustainability of food production

Expansion of the MANAGE Database with Forest and Drainage Studies

The “Measured Annual Nutrient loads from AGricultural Environments” (MANAGE) database was published in 2006 to expand an early 1980s compilation of nutrient export (load) data from cultivated and pasture/range land at the field or farm scale. Then in 2008, MANAGE was updated with 15 additional studies, and nitrogen (N) and phosphorus (P) concentrations in runoff were added. Since then, MANAGE has undergone significant expansion adding N and P water quality along with relevant management and site characteristic data from: (1) 30 runoff studies from forested land uses, (2) 91 drainage water quality studies from drained land, and (3) 12 additional runoff studies from cultivated and pasture/range land uses. In this expansion, an application timing category was added to the existing fertilizer data categories (rate, placement, formulation) to facilitate analysis of 4R Nutrient Stewardship, which emphasizes right fertilizer source, rate, time, and place. In addition, crop yield and N and P uptake data were added, although this information was only available for 21 and 7% of studies, respectively. Inclusion of these additional data from cultivated, pasture/range, and forest land uses as well as artificially drained agricultural land should facilitate expanded spatial analyses and improved understanding of regional differences, management practice effectiveness, and impacts of land use conversions and management techniques

Denitrifying Bioreactors for Nitrate Removal: A Meta-Analysis

Meta-analysis approaches were used in this first quantitative synthesis of denitrifying woodchip bioreactors. Nitrate removal across environmental and design conditions was assessed from 26 published studies, representing 57 separate bioreactor units (i.e., walls, beds, and laboratory columns). Effect size calculations weighted the data based on variance and number of measurements for each bioreactor unit. Nitrate removal rates in bed and column studies were not significantly different, but both were significantly higher than wall studies. In denitrifying beds, wood source did not significantly affect nitrate removal rates. Nitrate removal (mass per volume) was significantly lower in beds with \u3c6-h hydraulic retention times, which argues for ensuring that bed designs incorporate sufficient time for nitrate removal. Rates significantly declined after the first year of bed operation but then stabilized. Nitrogen limitation significantly affected bed nitrate removal. Categorical and linear assessments found significant nitrate removal effects with bed temperature; a Q10 of 2.15 was quite similar to other studies. Lessons from this meta-analysis can be incorporated into bed designs, especially extending hydraulic retention times to increase nitrate removal under low temperature and high flow conditions. Additional column studies are warranted for comparative assessments, as are field-based studies for assessing in situ conditions, especially in aging beds, with careful collection and reporting of design and environmental data. Future assessment of these systems might take a holistic view, reviewing nitrate removal in conjunction with other processes, including greenhouse gas and other unfavorable by-product production

Effectiveness of Denitrifying Bioreactors on Water Pollutant Reduction from Agricultural Areas

HighlightsDenitrifying woodchip bioreactors treat nitrate-N in a variety of applications and geographies.This review focuses on subsurface drainage bioreactors and bed-style designs (including in-ditch).Monitoring and reporting recommendations are provided to advance bioreactor science and engineering. Denitrifying bioreactors enhance the natural process of denitrification in a practical way to treat nitrate-nitrogen (N) in a variety of N-laden water matrices. The design and construction of bioreactors for treatment of subsurface drainage in the U.S. is guided by USDA-NRCS Conservation Practice Standard 605. This review consolidates the state of the science for denitrifying bioreactors using case studies from across the globe with an emphasis on full-size bioreactor nitrate-N removal and cost-effectiveness. The focus is on bed-style bioreactors (including in-ditch modifications), although there is mention of denitrifying walls, which broaden the applicability of bioreactor technology in some areas. Subsurface drainage denitrifying bioreactors have been assessed as removing 20% to 40% of annual nitrate-N loss in the Midwest, and an evaluation across the peer-reviewed literature published over the past three years showed that bioreactors around the world have been generally consistent with that (N load reduction median: 46%; mean ±SD: 40% ±26%; n = 15). Reported N removal rates were on the order of 5.1 g N m-3 d-1 (median; mean ±SD: 7.2 ±9.6 g N m-3 d-1; n = 27). Subsurface drainage bioreactor installation costs have ranged from less than $5,000 to$27,000, with estimated cost efficiencies ranging from less than $2.50 kg-1 N year-1 to roughly$20 kg-1 N year-1 (although they can be as high as $48 kg-1 N year-1). A suggested monitoring setup is described primarily for the context of conservation practitioners and watershed groups for assessing annual nitrate-N load removal performance of subsurface drainage denitrifying bioreactors. Recommended minimum reporting measures for assessing and comparing annual N removal performance include: bioreactor dimensions and installation date; fill media size, porosity, and type; nitrate-N concentrations and water temperatures; bioreactor flow treatment details; basic drainage system and bioreactor design characteristics; and N removal rate and efficiency

Aggressive therapy for patients with non-small cell lung carcinoma and synchronous brain-only oligometastatic disease is associated with long-term survival

Objectives: Optimal therapy for patients with non-small cell lung carcinoma (NSCLC) presenting with synchronous brain-only oligometastases (SBO) is not well defined. We sought to analyze the effect of differing therapeutic paradigms in this subpopulation. Materials and Methods: We retrospectively analyzed NSCLC patients with 1-4 SBO diagnosed between 1/2000 and 1/2011 at our institution. Patients with T0 tumors or documented Karnofsky Performance Status <70 were excluded. Aggressive thoracic therapy (ATT) was defined as resection of the primary disease or chemoradiotherapy whose total radiation dose exceeded 45 Gy. Cox proportional hazards and competing risks models were used to analyze factors affecting survival and first recurrence in the brain. Results: Sixty-six patients were included. Median follow-up was 31.9 months. Intrathoracic disease extent included 9 stage I, 10 stage II and 47 stage III patients. Thirty-eight patients received ATT, 28 did not. Patients receiving ATT were younger (median age 55 vs. 60.5 years, p=0.027) but were otherwise similar to those who did not. Receipt of ATT was associated with prolonged median overall survival (OS) (26.4 vs. 10.5 months; p<0.001) with actuarial 2-year rates of 54% vs. 26%. ATT remained associated with OS after controlling for age, thoracic stage, performance status and initial brain therapy (HR 0.40, p=0.009). On multivariate analysis, the risk of first failure in the brain was associated with receipt of ATT (HR 3.62, p=0.032) and initial combined modality brain therapy (HR 0.34, p=0.046). Conclusion: Aggressive management of thoracic disease in NSCLC patients with SBO is associated with improved survival. Careful management of brain disease remains important, especially for those treated aggressively

Ligand engagement of Toll-like receptors regulates their expression in cortical microglia and astrocytes

BACKGROUND: Toll-like receptor (TLR) activation on microglia and astrocytes are key elements in neuroinflammation which accompanies a number of neurological disorders. While TLR activation on glia is well-established to up-regulate pro-inflammatory mediator expression, much less is known about how ligand engagement of one TLR may affect expression of other TLRs on microglia and astrocytes. METHODS: In the present study, we evaluated the effects of agonists for TLR2 (zymosan), TLR3 (polyinosinic-polycytidylic acid (poly(I:C)), a synthetic analogue of double-stranded RNA) and TLR4 (lipopolysaccaride (LPS)) in influencing expression of their cognate receptor as well as that of the other TLRs in cultures of rat cortical purified microglia (>99.5 %) and nominally microglia-free astrocytes. Elimination of residual microglia (a common contaminant of astrocyte cultures) was achieved by incubation with the lysosomotropic agent L-leucyl-L-leucine methyl ester (L-LME). RESULTS: Flow cytometric analysis confirmed the purity (essentially 100 %) of the obtained microglia, and up to 5 % microglia contamination of astrocytes. L-LME treatment effectively removed microglia from the latter (real-time polymerase chain reaction). The three TLR ligands robustly up-regulated gene expression for pro-inflammatory markers (interleukin-1 and interleukin-6, tumor necrosis factor) in microglia and enriched, but not purified, astrocytes, confirming cellular functionality. LPS, zymosan and poly(I:C) all down-regulated TLR4 messenger RNA (mRNA) and up-regulated TLR2 mRNA at 6 and 24 h. In spite of their inability to elaborate pro-inflammatory mediator output, the nominally microglia-free astrocytes (>99 % purity) also showed similar behaviours to those of microglia, as well as changes in TLR3 gene expression. LPS interaction with TLR4 activates downstream mitogen-activated protein kinase and nuclear factor-κB signalling pathways and subsequently causes inflammatory mediator production. The effects of LPS on TLR2 mRNA in both cell populations were antagonized by a nuclear factor-κB inhibitor. CONCLUSIONS: TLR2 and TLR4 activation in particular, in concert with microglia and astrocytes, comprise key elements in the initiation and maintenance of neuropathic pain. The finding that both homologous (zymosan) and heterologous (LPS, poly(I:C)) TLR ligands are capable of regulating TLR2 gene expression, in particular, may have important implications in understanding the relative contributions of different TLRs in neurological disorders associated with neuroinflammation

Saturated Buffers: What Is Their Potential Impact across the US Midwest?

Because saturated buffers are a new conservation practice, there has been no large-scale assessment of their potential to aid in meeting water quality goals. Publicly available data were used in a stepwise fashion within a geographic information system to estimate the total stream length suitable for saturated buffer implementation across the US Midwest region and the resulting potential nitrate loading reduction from widespread saturated buffer implementation. Approximately 37,760 km of streams (or 75,520 km of stream bank) was deemed suitable to host a saturated buffer, and 3.85 million ha of drained land has the potential to drain to a saturated buffer. These results suggest that implementing saturated buffers widely could result in a 5 to 10% reduction of the estimated N load from midwestern tile-drained land. Saturated buffers can be an important component of plans to achieve water quality goals

Scenario-based techno-economic analysis of pumped denitrification bioreactors

Pumped denitrification bioreactors are currently being assessed in the field to extend the use of traditional, subsurface drainage bioreactors. Pumped bioreactors for the treatment of drainage ditches, surface waters, and cisterns intercepting drainage were evaluated to provide a basis of the unit cost of bioreactor operation ($kg NO3–N removed−1) under a variety of scenarios. The unit costs were modeled using a techno-economic analysis. The variables assessed in the analysis included nitrate removal rate, bioreactor lifespan, and operating periods, which were assumed. To evaluate the impact of these variables on the unit cost, a sensitivity analysis was conducted where one variable was adjusted (e.g., lifespan) while the other variables were kept the same as a traditional bioreactor. The cistern and supplemental surface water bioreactors were larger in size and had similar unit costs ranging from ∼$5 to $27 kg NO3–N removed−1 for all scenarios except for the low mass removal and worst-case scenarios. The smaller, ditch diversion bioreactor had unit costs in the best- and worst-case scenarios in the range of$24 to $619 kg NO3–N removed−1, respectively. A breakeven analysis indicated increasing the mass removal rate of the bioreactors and ensuring an operating period greater than 6-months had the greatest impact on reducing the unit cost compared to a traditional bioreactor. Overall, the larger-scale surface water and cistern bioreactors had comparable, but slightly higher, unit costs than traditional bioreactors under most scenarios evaluated. This information can be used to optimize and inform of the potential of pumped bioreactor systems.This article is published as Hartfiel, Lindsey M., Carolina Díaz-García, Laura E. Christianson, and Michelle L. Soupir. "Scenario-based techno-economic analysis of pumped denitrification bioreactors." Water Resources and Economics (2024): 100238. doi: https://doi.org/10.1016/j.wre.2024.100238. © 2024 The Authors. This is an open access article under the CC BY-NC-ND license. http://creativecommons.org/licenses/by-nc-nd/4.0/