Sites In Illinois Research Articles

Optimizing bioenergy sorghum productivity and nutrient removal in Illinois: Impact of nitrogen fertilization under diverse marginal conditions

Context or problemBioenergy sorghum (Sorghum bicolor L. Moench) is a promising crop for contributing to the United States bioenergy supply. However, the varying limitations of the marginal lands targeted for its cultivation present a management challenge. ObjectiveThis two-year study aimed to investigate how the limitations associated with marginal cropland impact the effects of nitrogen fertilization on the yield of bioenergy sorghum and the uptake of 11 macro- (N, P, K, Ca, Mg, and S) and micronutrients (Fe, Mn, Zn, Cu, and B). MethodsThe study contrasted prime cropland in central Illinois (Urbana) with three marginal cropland sites in southern (Ewing) and central Illinois (Fairbury and Pesotum). These marginal cropland sites are characterized by varying limitations, including low soil fertility (P and K limitations), leaching and erosion, and flooding, respectively. Four nitrogen rates (0, 56, 112, and 168 kg N ha−1) were tested under eight environments. ResultsThe average yields and ranges of sorghum biomass were 20.2 (17.0–23.2) Mg ha−1 in Urbana, 18.1 (13.1–19.8) Mg ha−1 in Ewing, 13.8 (9.0–17.3) Mg ha−1 in Fairbury, and 23.3 (14.6–33.0) Mg ha−1 in Pesotum. Optimal N rates were 56 N in Pesotum and 112 N in Urbana, Ewing, and Fairbury. Tissue macronutrient contents in Urbana were generally higher than in the marginal croplands, while micronutrient contents did not show discernible trends. Increasing N rate generally correlated with the macronutrient removal except in Ewing. ConclusionComparable sorghum biomass yields were observed between prime and marginal croplands (averaging 18.3 Mg ha−1), but optimal N rates varied between 56 N and 112 N. This suggests that yield gaps can be narrowed by applying the optimal N rates for the respective locations. However, increased removals of macronutrients, especially P and K, with increasing yields indicate the need to revise fertilizer recommendations, particularly for soils deficient in these nutrients. Implications or significanceOur study suggests that while sorghum production on marginal cropland is feasible, N management needs to be adapted to the unique limitations associated with various types of marginal cropland.

Bird Species Use of Bioenergy Croplands in Illinois, USA—Can Advanced Switchgrass Cultivars Provide Suitable Habitats for Breeding Grassland Birds?

Grassland birds have sustained significant population declines in the United States through habitat loss, and replacing lost grasslands with bioenergy production areas could benefit these species and the ecological services they provide. Point count surveys and autonomous acoustic monitoring were used at two field sites in Illinois, USA, to determine if an advanced switchgrass cultivar that is being used for bioenergy feedstock production could provide suitable habitats for grassland and other bird species. At the Brighton site, the bird use of switchgrass plots was compared to that of corn plots during the breeding seasons of 2020–2022. At the Urbana site, the bird use of restored prairie, switchgrass, and Miscanthus × giganteus was studied in the 2022 breeding season. At Brighton, Common Yellowthroat, Dickcissel, Grasshopper Sparrow, and Sedge Wren occurred on switchgrass plots more often than on corn; Common Yellowthroat and Dickcissel increased on experimental plots as the perennial switchgrass increased in height and density over the study period; and the other two species declined over the same period. At Urbana, Dickcissel was most frequent in prairie and switchgrass; Common Yellowthroat was most frequent in miscanthus and switchgrass. These findings suggest that advanced switchgrass cultivars could provide suitable habitats for grassland birds, replace lost habitats, and contribute to the recovery of these vulnerable species.

Registration of ‘Independence’ switchgrass

AbstractSwitchgrass (Panicum virgatum L.), a valuable forage and bioenergy crop, is established more easily than other native perennial warm‐season grasses, but its establishment is still slower than that of annual crops. Vigorous switchgrass establishment is crucial for achieving its full potential yield and for effectively competing with weeds for water and nutrient availability. To satisfy this demand, ‘Independence’ (Reg. no. CV‐295, PI 704577) switchgrass was developed at the University of Illinois at Urbana‐Champaign. Independence was selected for establishment vigor, winter survivorship, and high biomass yield for two cycles from ‘Kanlow’. It is characterized by rapid establishment, robust seedling growth, and the capacity to achieve peak production by the second year. Independence is well adapted to USDA hardiness zones 5b–7b. In field experiments conducted from 2016 to 2017, averaged over seven locations and all years, Independence annually yielded 13 Mg ha−1 of biomass, outperforming ‘Cave‐in‐Rock’ by 31%, ‘Liberty’ by 15%, ‘Shawnee’ by 42%, ‘Summer’ by 81%, and ‘Sunburst’ by 129%. In wet marginal sites in Illinois from 2020 to 2023, Independence exhibited an average biomass yield of 12 Mg ha−1, outperforming Shawnee by 31%, Liberty by 27%, and Kanlow by 19%, indicating its potential use on less productive land for annual crops. Independence was publicly released by the University of Illinois at Urbana‐Champaign in October 2021.

Nitrogen fertilization effects on aged Miscanthus × giganteus stands: Exploring biomass yield, yield components, and biomass prediction using in‐season morphological traits

AbstractFor sustainable biomass production of Miscanthus × giganteus (hereafter miscanthus), understanding the impact of stand age and nitrogen (N) fertilization on biomass yield is crucial. This study investigated the effects of varying N fertilization rates (0, 56, 112, and 168 kg N ha−1) on yield components (tiller height, density, and weight) and their correlations with end‐of‐season biomass yield in miscanthus. We also explored end‐of‐season biomass yield prediction using in‐season traits (canopy height, leaf area index, and leaf chlorophyll content [LCC]). The study was conducted at two sites in Illinois: a previously unfertilized 10‐year‐old miscanthus research stand at Urbana and a 16‐year‐old commercial stand at Pesotum with a history of annual 56N application. Results from 2018 to 2021 in Urbana and 2020 to 2021 in Pesotum showed increased biomass yields with N fertilization, varying by rate, year, and location. Biomass yield in Pesotum peaked at 56N, while in Urbana, it increased significantly at 112 kg N ha−1. Biomass yield was strongly correlated with tiller height and weight measured at Urbana across N rates. Morphological traits measured every 2–3 weeks during the 2020 and 2021 growing seasons showed that canopy height was the strongest single predictor of miscanthus biomass yield, followed by LCC. Mid‐August to September measurements of these traits were the best predictors of biomass yield. Multiple regressions involving the canopy height and LCC further improved yield predictions. We conclude that while N enhances biomass yields of aging miscanthus, the optimum rate depends on the site, environmental conditions, and management history.

Joe Louis: A Late Fisher Phase Village on the Little Calumet River

Abstract Excavations at the Joe Louis site (11CK284) in northeastern Illinois provide insight into village life along the Little Calumet River between the mid-fourteenth and late fifteenth centuries AD. In addition to evidence for their horticultural and other subsistence activities, the assemblage shows that site occupants were making stone tools and pottery, processing hides, making clothing, and possibly producing bird-wing fans. Structured deposits of bone and antler hoes, mussel shell, and specific plant and animal remains document the relational entanglements of the site's occupants, both human and otherwise. Given the geographically central location of the site at the margins of two major cultural areas (Oneota and Fort Ancient), as well as the overlapping boundaries with Langford and Huber peoples, Joe Louis villagers may have been actively negotiating social networks and identities through their material products as well as ritual gatherings. These negotiations may have enabled and encouraged coalescent occupations (Langford and Fisher, Fisher and Huber) at other sites in the region.

Design and partial validation of novel eDNA qPCR assays for three common North American tick (Arachnida: Ixodida) species

AbstractThe range expansion of ticks to higher latitudes poses a severe threat to human health exposing human populations who had no prior contact with ticks to several harmful tick‐borne diseases. Early detection of ticks in new areas is critical to help inform the public and medical professionals of the dangers associated with tick encounters. Environmental DNA represents a novel survey method that could provide reliable records of tick occurrences and timely warnings of their range expansions. In this study, we designed novel eDNA qPCR assays for three common North American tick species (Dermacentor variabilis, Amblyomma americanum, and Ixodes scapularis) and tested them on 51 samples of grasses and leaf litter collected from 12 grassland and forest sites in central and southern Illinois. We provide in silico and in vitro validation of all three assays; however, we were unable to generate any positive detections from field samples. Our lack of eDNA detections likely stems from low eDNA deposition rates coupled with rapid degradation in grasslands and forests, a problem exacerbated by terrestrial eDNA sampling methods limited by volume of substrate. We provide recommendations for improving sample collection methods to increase detection probability in future efforts. Continued research should focus on the viability of eDNA to detect small terrestrial invertebrates, like ticks, and it potential as early warning indicator of the spread of vector‐borne diseases.

(R)-(+)-γ-Decalactone is Conserved in North America as a Pheromone Component of Osmoderma eremicola (Coleoptera: Scarabaeidae) and a Kairomone of Elater abruptus (Coleoptera: Elateridae).

The scarab genus Osmoderma (Coleoptera: Scarabaeidae) includes several large species called hermit beetles that develop within dead and decaying hardwood trees. Males of at least three Palearctic species produce the aggregation-sex pheromone (R)-(+)-γ-decalactone, including the endangered O. eremita (Scopoli). However, hermit beetles have received less attention in the western hemisphere, resulting in a large gap in our knowledge of the chemical ecology of Nearctic species. Here, we identify (R)-( +)-γ-decalactone as the primary component of the aggregation-sex pheromone of the North American species Osmoderma eremicola (Knoch). Field trials at sites in Wisconsin and Illinois revealed that both sexes were attracted to lures containing (R)-(+)-γ-decalactone or the racemate, but only males of O. eremicola produced the pheromone in laboratory bioassays, alongside an occasional trace of the chain-length analog γ-dodecalactone. Females of the congener O. scabra (Palisot de Beauvois) were also significantly attracted by γ-decalactone, suggesting further conservation of the pheromone, as were females of the click beetle Elater abruptus Say (Coleoptera: Elateridae), suggesting that this compound may have widespread kairomonal activity. Further research is needed to explore the behavioral roles of both lactones in mediating behavioral and ecological interactions among these beetle species.

Wastewater-based monitoring of the nitazene analogues: First detection of protonitazene in wastewater

Synthetic opioids, particularly the nitazene analogues class, have become a public health concern due to their high potency. Wastewater-based epidemiology can detect community use of these compounds. The objective of this work was to detect nitazene analogues in wastewater from samples collected from eight sites in the United States. Influent wastewater samples were collected from eight sites in seven states (Arizona, Oregon, New Mexico, Illinois, New Jersey, Washington and Georgia) in the United States. Samples were collected from each site on three days between 27 December 2022 and 4 January 2023, acidified on collection, stored frozen and shipped to Arizona State University (Tempe, AZ) for sample processing. Samples were then shipped to The University of Queensland (Brisbane, Australia) for sample analysis. Protonitazene was found in samples collected from two sites in Washington and Illinois. The concentration was estimated up to 0.5 ng/L, with estimated excreted mass loads up to 0.3 mg/day/1000 people. This work has shown that it is possible to detect nitazene analogues in wastewater using a combination of sample pre-concentration and sensitive instrumentation, thereby further expanding the utility of wastewater-based epidemiology.

Dynamic, multi-scale analyses indicate site- and landscape-level forest cover drive Yellow-billed and Black-billed Cuckoo interannual turnover.

Studies of habitat use in breeding birds often assume species have relatively stable breeding distributions. Some species, however, display considerable year-to-year variability, complicating efforts to determine suitable or preferred habitats. After returning to their breeding range, Black-billed Cuckoos (Coccyzus erythropthalmus) and Yellow-billed Cuckoos (C. americanus) are thought to range widely before nesting, resulting in high rates of interannual breeding-site turnover, potentially contributing to conflicting habitat associations found in past studies. However, difficulty detecting these rare and declining species could lead to overinflated estimates of interannual turnover. Using broadcast surveys to increase detection probability, we collected detection/non-detection data in 2019 and 2020 at 41 publicly owned sites in Illinois and performed a dynamic, multi-scale occupancy analysis for each species to separate detection probability from potential interannual turnover and determine landscape and small-scale variables driving habitat use and occupancy dynamics. We found strong support for interannual turnover for both species based on poor performance of non-dynamic models and variation in estimated annual occupancy (20% and 21% increase between years for Black-billed and Yellow-billed Cuckoos, respectively). Black-billed Cuckoos persisted at sites with less forest in the surrounding landscape and used areas with denser understory vegetation. Yellow-billed Cuckoos colonized sites with greater canopy cover, avoided developed landscapes, and used areas with a shorter subcanopy layer. The dynamic nature of habitat use in these two cuckoo species suggests the importance of coordinating management and conservation across a broader spatial scale. Managing for larger patches of dense shrubs in less forested landscapes would benefit Black-billed Cuckoos while Yellow-billed cuckoos would benefit from management creating forested areas with open understories in less-developed landscapes.

Evaluating Different Methods for Determining Erythrocyte Sedimentation Rate in Free-Living Blanding's Turtles (Emydoidea blandingii).

Characterizing host factors affecting individual health can be important in the conservation of many chelonians, including the Blanding's turtle (Emydoidea blandingii). However, many routine clinical pathology tests do not reliably detect differences in health status in reptiles. The erythrocyte sedimentation rate (ESR) has been shown to characterize inflammation in many species, including tortoises, and may be useful in assessing Blanding's turtles. The purpose of our study was to evaluate two methods of ESR measurement in free-ranging Blanding's turtles. Sixty Blanding's turtles captured at two sites in Illinois received a complete physical examination, and blood was collected for determination of packed cell volume, total solids, and ESR with both microhematocrit tubes and commercial kits (Winpette). Method agreement was assessed with Passing-Bablok regression. Associations between ESR and demographic, environmental, and health factors were determined by linear regression. The microhematocrit tube method proportionately overestimated ESR compared with the Winpette. With the use of both measurement methods, ESR was significantly different between study sites, higher in adult Blanding's turtles, and higher in females that were gravid compared with those that were not. ESR was also negatively associated with packed cell volume. ESR values in Blanding's turtles are comparable to other reptiles, and although microhematocrit tube and Winpette results are not interchangeable, their associations with biological predictors are similar, and either method has the potential to be used with separate reference intervals to assess turtles for inflammatory conditions.

Avoiding mortality: timing prescribed burns in ornate box turtle habitat

AbstractFire is a vital management tool for maintaining prairie ecosystems. Prescribed burns control invasive species, regulate succession, stimulate plant growth, and are a cheap and effective method for removing excess biomass; however, fire can also inadvertently cause wildlife mortality, placing land managers in a challenging situation. Turtles are especially at risk of mortality from fire because of their low mobility and population sensitivity to reductions in adult survival. We studied ornate box turtles (Terrapene ornata) at 3 sites in Illinois, USA, from 2019–2022 to determine the best predictors of above‐ground activity so land managers can conduct prescribed burns when turtles are underground. We used turtle shell temperature, air temperature, soil temperature, and precipitation data to develop a predictive model of above‐ground activity. The best model for predicting above‐ground activity included an interaction between day of year and current air temperature. Earlier in spring and later in fall, above‐ground activity is more likely at higher air temperatures compared to later in spring and earlier in fall when the same likelihood of above‐ground activity is predicted at lower air temperatures. In spring, we recommend burning in Illinois ornate box turtle habitat before 1 April when air temperature is <10°C and in fall after 1 November when air temperature is <15°C. Above these temperature thresholds, there is a >5% likelihood that turtles in northern populations are above ground.

Modeling the Chronology of a Late Precontact Site Using Radiocarbon and Trade Good Dates: Middle Grant Creek

Abstract Late precontact- and contact-period sites often produce multiple sources of chronological information, including stratigraphy, radiocarbon dates, European trade goods, and pottery seriation patterns. In this article, we describe a step-by-step approach to incorporating such information in an OxCal-based Bayesian chronology model, with special emphasis on incorporating trade-good dating into radiocarbon-based modeling. The Middle Grant Creek site in Illinois is an American Indian site that has yielded a number of European copper and brass trade goods along with extensive ceramic, faunal, floral, and lithic artifacts. Our modeling addresses issues resulting from an inversion in the radiocarbon calibration curve during the late precontact period and produces surprisingly different results depending on the boundary conditions applied to the model. We consider the probabilities produced by the models, propose the most likely chronology for Middle Grant Creek, and provide detailed OxCal scripts and examples that other researchers may adapt to their circumstances and preferences. We also describe lessons learned related to chronological modeling of sites where the radiocarbon curve contains significant inversions.

Testing the accuracy of a Rights-of-Way pollinator habitat scoring system

Habitat loss is a major cause of pollinator declines, and there is increased interest by the public in creating pollinator-friendly lands. Electric and transportation rights-of-way (ROW) present an opportunity for large amounts of land to be managed to support pollinators. The Rights of Way as Habitat Working Group developed a pollinator habitat scorecard with the goal of establishing a consistent valuation method for pollinator habitat quality in ROWs. In this study, we tested how well the pollinator habitat score aligns with several measures of pollinator biodiversity in electric transmission ROWs. We used pan traps and timed observations to quantify the communities of lepidopterans and bee hymenopterans at 12 ROW sites in Illinois, USA. The 12 study sites were divided across four geographical locations in the greater Chicago metropolitan area, with each location including three sites managed in different ways: turf-grass lawn, restored prairie, and weedy old-field. We found that the pollinator habitat score was not a significant predictor of bee and lepidopteran pollinator biodiversity. However, the pollinator habitat score did differ significantly among the ROW management types, with lawn sites receiving lower scores than prairie or old-field sites. These results indicate that the pollinator habitat scorecard may not, in its current form, be appropriate for comparing pollinator biodiversity among sites, although it does capture differences in pollinator resource availability at a local scale. We suggest that the scorecard as currently designed may be more useful in monitoring temporal changes at individual sites rather than making spatial comparisons among sites. We also recommend that future studies continue to examine ways to make the pollinator habitat scorecard a more universally applicable tool, because an accurate, simple scorecard would provide valuable information to ROW land managers.

Multi-model based soil moisture simulation approach under contrasting weather conditions

We developed and tested a multi-model based soil moisture simulation approach for improving parameterization scheme and its transferability under contrasting weather conditions. Three popular hydrologic models in combination with three optimization schemes were adapted to consider uncertainties in physical and optimization model structures for estimating near-surface soil moisture dynamics. In order to improve parameterization and its transferability under contrasting weather conditions, a multiple set of weights based on different land surface wetness conditions (wet, normal, and dry) were used using a Multiple Weighting Algorithm (MWA). A Differential Split Sample Testing (DSST) scheme was used to test the transferability of parameterizations in the optimization and physical model domains. Data from three experimental sites (Little Washita, LW13 in Oklahoma, Everglades in Florida and Bondville/Olney sites in Illinois) were used to verify our proposed approach. Our findings indicated that the multi-model outputs were highly influenced both by the physical and optimization model structures. Overall, our approach performed well in the test of transferability under different weather conditions. However, we confirmed that the overfitted parameters (to the in-situ measurements during the calibration period) due to the optimization model structures can undermine the transferability of multi-model approach. Also, our findings indicate that the estimated soil hydraulic properties during the dry years can be limited in representing the soil wetness conditions for the wet years.

Simulated leaching of PFAS from land-applied municipal biosolids at agricultural sites

Biosolids are an important resource for agricultural practice but have recently received increased focus as a potential source of per- and polyfluoroalkyl substances (PFAS) in the environment. Few studies have investigated the transport of PFAS through the unsaturated zone under conditions relevant to biosolids application sites. Herein, the unsaturated flow and transport model HYDRUS is used to evaluate the leaching of per- and polyfluoroalkyl substances (PFAS) from land-applied biosolids used in agricultural practice to determine the impacts of PFAS leaching on underlying groundwater resources. This numerical case study was based on conditions and operations at two test sites in central Illinois where biosolids were applied at agronomic rates and where PFAS contents and desorption characteristics were previously characterized. Each site possessed different vadose zone soil textural heterogeneity. Simulations were performed under actual present-day meteorological conditions and extended 150 years beyond the initial biosolids application. These long-term simulations demonstrate how soil equilibrium sorption/desorption processes within the biosolids-amended surface soils effectively control the transport rate of individual PFAS to groundwater. Air-water interfacial (AWI) adsorption, which is sometimes considered to be a significant source of PFAS retention in vadose zone soils, was observed to have minimal impacts on PFAS leaching rates within the biosolids-amended surface soils at these sites. Additionally, the impact of AWI adsorption was found to be most significant for PFAS transport within the underlying vadose zone soils when these soils were more texturally homogeneous and considerably less significant within the texturally heterogeneous soils represented herein. The results of multiple long-term simulations were used to develop an empirical equation that relates predicted maximum PFAS pore-water concentrations reaching the saturated zone with changes in PFAS concentrations in the biosolids-amended soil for various biosolids re-application events. This approach is shown to be very useful in developing site-specific PFAS soil screening levels and/or maximum leachate levels for PFAS in support of establishing best management practices (BMPs) for land application of biosolids.

Estimating local eradication costs for invasive Miscanthus populations throughout the eastern and midwestern United States

AbstractSeveral Miscanthus species are cultivated in the U.S. Midwest and Northeast, and feral populations can displace the native plant community and potentially negatively affect ecosystem processes. The monetary cost of eradicating feral Miscanthus populations is unknown, but quantifying eradication costs will inform decisions on whether eradication is a feasible goal and should be considered when totaling the economic damage of invasive species. We managed experimental populations of eulaliagrass (Miscanthus sinensis Andersson) and the giant Miscanthus hybrid (Miscanthus × giganteus J.M. Greef & Deuter ex Hodkinson & Renvoize) in three floodplain forest and three old field sites in central Illinois with the goal of eradication. We recorded the time invested in eradication efforts and tracked survival of Miscanthus plants over a 5-yr period, then estimated the costs associated with eradicating these Miscanthus populations. Finally, we used these estimates to predict the total monetary costs of eradicating existing M. sinensis populations reported on EDDMapS. Miscanthus populations in the old field sites were harder to eradicate, resulting in an average of 290% greater estimated eradication costs compared with the floodplain forest sites. However, the cost and time needed to eradicate Miscanthus populations were similar between Miscanthus species. On-site eradication costs ranged from $390 to $3,316 per site (or $1.3 to $11 m−2) in the old field sites, compared with only $85 to $547 (or $0.92 to $1.82 m−2) to eradicate populations within the floodplain forests, with labor comprising the largest share of these costs. Using our M. sinensis eradication cost estimates in Illinois, we predict that the potential costs to eradicate populations reported on EDDMapS would range from $10 to $37 million, with a median predicted cost of $22 million. The monetary costs of eradicating feral Miscanthus populations should be weighed against the benefits of cultivating these species to provide a comprehensive picture of the relative costs and benefits of adding these species to our landscapes.

Variation in Susceptibility to Permethrin in Culex pipiens and Culex restuans Populations in the Great Lakes Region of the United States.

Two Culex pipiens form Pipiens colony strains and a field population of Cx. restuans from Michigan were susceptible and a Cx. pipiens form Molestus colony strain was comparatively less susceptible to a dose of 43 μg/ml of permethrin in Centers for Disease Control and Prevention (CDC) bottle bioassays. Using this diagnostic dose and these populations as controls, adult female Cx. pipiens and Cx. restuans were reared from egg rafts from 28 sites in Illinois, Ohio, Michigan, Iowa, Indiana, Wisconsin, and Minnesota. Tested mosquitoes showed high mortality in populations from 12 sites, less mortality (90-96%) at 9 sites, and less than 90% mortality from 7 sites during 30-min exposures. However, all tested populations showed 97-100% mortality at 60 min, indicating low phenotypic penetrance of resistance factors. These results indicate variation in susceptibility to permethrin in populations of West Nile virus vectors in the Great Lakes region of the United States, with evidence of modest resistance at 7 of 28 (25%) of the sampled populations.

Mapping the Chicago Portage: Seventeenth-Century Explorations by Jolliet, Marquette, La Salle, and Joutel

On their return to Canada in 1673, Louis Jolliet’s group became the first Europeans documented to have passed from the Mississippi River watershed to the Great Lakes watershed via the Chicago Portage. This carrying place, between the Des Plaines and Chicago Rivers, would remain a politically and commercially important location during the fur trade era. A podcast by a group of Chicago historians, writers, and artists has promoted the assertion that a route south of Chicago, different from that recognized as one of only two National Historic Sites in Illinois, was actually the Chicago Portage Region used by such explorers as Louis Jolliet, Father Jacques Marquette, René-Robert Cavelier, Sieur de La Salle, and Henri Joutel. However, the accounts of the seventeenth-century French travelers confirm the 1928 work that established the location of the portage region and served as the foundation for its designation by the National Park Service in 1952.

Development of a data-assimilation system to forecast agricultural systems: A case study of constraining soil water and soil nitrogen dynamics in the APSIM model

As we face today's large-scale agricultural issues, the need for robust methods of agricultural forecasting has never been clearer. Yet, the accuracy and precision of our forecasts remains limited by current tools and methods. To overcome the limitations of process-based models and observed data, we iteratively designed and tested a generalizable and robust data-assimilation system that systematically constrains state variables in the APSIM model to improve forecast accuracy and precision. Our final novel system utilizes the Ensemble Kalman Filter to constrain model states and update model parameters at observed time steps and incorporates an algorithm that improves system performance through the joint estimation of system error matrices. We tested this system at the Energy Farm, a well-monitored research site in central Illinois, where we assimilated observed in situ soil moisture at daily time steps for two years and evaluated how assimilation impacted model forecasts of soil moisture, yield, leaf area index, tile flow, and nitrate leaching by comparing estimates with in situ observations. The system improved the accuracy and precision of soil moisture estimates for the assimilation layers by an average of 42% and 48%, respectively, when compared to the free model. Such improvements led to changes in the model's soil water and nitrogen processes and, on average, increased accuracy in forecasts of annual tile flow by 43% and annual nitrate loads by 10%. Forecasts of aboveground measures did not dramatically change with assimilation, a fact which highlights the limited potential of soil moisture as a constraint for a site with no water stress. Extending the scope of previous work, our results demonstrate the power of data assimilation to constrain important model estimates beyond the assimilated state variable, such as nitrate leaching. Replication of this study is necessary to further define the limitations and opportunities of the developed system.

Plasma electrophoresis profiles of Blanding's turtles (Emydoidea blandingii) and influences of month, age, sex, health status, and location.

Baseline plasma electrophoresis profiles (EPH) are important components of overall health and may aid in the conservation and captive management of species. The aim of this study was to establish plasma protein fractions for free-ranging Blanding's turtles (Emydoidea blandingii) and evaluate differences due to age class (adult vs. sub-adult vs. juvenile), sex (male, female, or unknown), year (2018 vs. 2019), month (May vs. June vs. July), health status, and geographical location (managed vs. unmanaged sites). Blood samples were obtained from 156 Blanding's turtles in the summer of 2018 and 129 in 2019 at two adjacent sites in Illinois. Results of the multivariate analysis demonstrated that age class, sex, year, month, health status, and geographical location all contributed to the variation observed in free-ranging populations. Adult females had the highest concentration of many protein fractions, likely associated with reproductive activity. Juveniles had lower protein concentrations. Temperature and rainfall differences between years impacted concentrations between 2018 and 2019, while May and June of both years saw higher levels in some protein fractions likely due to peak breeding and nesting season. Individuals with evidence of trauma or disease also showed increased plasma protein fractions when compared to those that were considered healthy. The two sites showed a wide/large variation over the two years. All of these factors emphasize the importance of considering multiple demographic or environmental factors when interpreting the EPH fractions. Establishing ranges for these analytes will allow investigation into disease prevalence and other environmental factors impacting this endangered species.