Matthew Mark Trumbull was a Londoner who immigrated at the age of twenty. Within ten years of his arrival in America, he had become a lawyer in Butler County, Iowa; two years later a member of the ...state legislature; and two years after that a captain in the Union Army. By the end of the Civil War, he was a brevet brigadier general, and in his later years he was an author and lecturer. Kenneth Lyftogt's biography details the amazing life of this remarkable man, also shedding light on the histories of the Third Iowa Volunteer Infantry and the Ninth Iowa Volunteer Cavalry.
Electromagnetic induction (EMI) has been used to characterize the spatial variability of soil properties since the late 1970s. Initially used to assess soil salinity, the use of EMI in soil studies ...has expanded to include: mapping soil types; characterizing soil water content and flow patterns; assessing variations in soil texture, compaction, organic matter content, and pH; and determining the depth to subsurface horizons, stratigraphic layers or bedrock, among other uses. In all cases the soil property being investigated must influence soil apparent electrical conductivity (ECa) either directly or indirectly for EMI techniques to be effective. An increasing number and diversity of EMI sensors have been developed in response to users' needs and the availability of allied technologies, which have greatly improved the functionality of these tools. EMI investigations provide several benefits for soil studies. The large amount of georeferenced data that can be rapidly and inexpensively collected with EMI provides more complete characterization of the spatial variations in soil properties than traditional sampling techniques. In addition, compared to traditional soil survey methods, EMI can more effectively characterize diffuse soil boundaries and identify areas of dissimilar soils within mapped soil units, giving soil scientists greater confidence when collecting spatial soil information. EMI techniques do have limitations; results are site-specific and can vary depending on the complex interactions among multiple and variable soil properties. Despite this, EMI techniques are increasingly being used to investigate the spatial variability of soil properties at field and landscape scales.
•We review the use of electromagnetic induction (EMI) techniques in soils studies.•EMI allows the rapid collection of large amounts of spatially-oriented data.•Diffuse boundaries between soil map units can be well characterized with EMI.•A wide range of soil properties can be characterized.
William Vermilion (1830-1894) served as a captain in Company F of the 36th Iowa Infantry from October 1862 until September 1865. Although he was a physician in Iconium in south central Iowa at the ...start of the war, after it ended he became a noted lawyer in nearby Centerville; he was also a state senator from 1869 to 1872. Mary Vermilion (1831-1883) was a schoolteacher who grew up in Indiana; she and William married in 1858. In this volume historian Donald Elder provides a careful selection from the hundreds of supportive, informative, and heart-wrenching letters that they wrote each other during the war-the most complete collection of letters exchanged between a husband and a wife during the Civil War.
In this work, a soil carbon, aggregation, and structure turnover (CAST) model was developed based on the concept suggested by many authors in the scientific literature that macro-aggregates are ...formed around particulate organic matter, followed by the release of micro-aggregates. A simplified mechanistic Nitrogen model was also developed. The CAST model was evaluated by field data of cropland to set-aside conversions of Critical Zone Observatories in Greece (fine textured Mediterranean) and Iowa (coarse textured humid continental). The model was calibrated successfully to capture the carbon content and the C-to-N ratio content of the pools comprising the three aggregate types (macro-aggregates: >250μm, micro-aggregates: 53–250μm, silt–clay sized aggregates: <53μm) in both sites. The soil system reached maximum macro-aggregation/porosity and minimum bulk density after 7 and 14years of cropland to set aside conversion in Greece and Iowa, respectively, according to the model results. From then onward, macro-aggregate disruption presented a constant inter-annual variability and any further SOC increase was due to micro-aggregation resulting in the increase of bulk density and decrease of porosity towards a stable value. Sensitivity and Monte Carlo uncertainty analysis on model parameters suggested that the most uncertain state variables affected by most model parameters is the carbon mass in the silt–clay size aggregates and the silt–clay mass itself. Higher size aggregates and their carbon content as well as soil structure parameters such as porosity and bulk density do not exhibit significant sensitivity to model parameters. Validation and improvement of the CAST model could assist in revealing the primary factors determining organic matter, aggregation, and structure turnover in different ecosystems. Obtaining this capability should allow better prediction of the response of the soil system to management practices, landuse changes, and climate change in order to design and optimize the appropriate measures/practices.
•Maximum macro-aggregation/porosity & minimum bulk density after 7 & 14y (GR-IA)•Afterwards constant inter-annual variability of macro-aggregate disruption•Any further SOC increase attributed to micro-aggregation•Indications that substantial parts of mineral surfaces are not covered by OM•Most uncertain state variables related with the silt–clay size aggregates
High grain production of corn (Zea mays L.) can be maintained by adding inorganic N fertilizer, and also by using crop rotations that include alfalfa (Medicago sativa L.), but the relative impact of ...these management practices on soil quality is uncertain. We examined the effects on soil of N fertilization rate (0, 90, 180, 270 kg ha(-1), corn phase only) in four cropping systems: CC, continuous corn; CS, corn-soybean Glycine max (L.) Merr.; CCOA, corn-corn-oat (Avena sativa L.)-alfalfa; and corn-oat-alfalfa-alfalfa (COAA). The 23- and 48-yr-old experimental sites, situated in northeast (Nashua) and north central (Kanawha) Iowa, were in a replicated split-plot design and managed with conventional tillage. At Nashua, we measured available N, potential net N mineralization and microbial biomass C (MBC) throughout the growing season; all were significantly higher in the CCOA system. At both sites, post-harvest N stocks, and soil organic C (SOC) concentrations were significantly higher in systems containing alfalfa. Grain yield was most strongly correlated with soil N properties. At Nashua, N fertilizer additions resulted in significantly lower soil pH (0- to 15-cm depth) and lower exchangeable Ca, Mg, and K and cation exchange capacity (CEC) in the CC and CCOA systems. In an undisturbed prairie reference site for Nashua, low available N, low pH, and high CEC suggested a strong influence of the vegetation on nutrient cycling. In terms of management of soil fertility, inclusion of alfalfa in the rotation differed fundamentally from addition of N fertilizer because high yield was maintained with fewer adverse effects on soil quality.
Nitrate-nitrogen export from the Raccoon River watershed in west-central Iowa is among the highest in the United State and contributes to impairment of downstream water quality. We examined a rare ...long-term record of streamflow and nitrate concentration data (1972–2000) to evaluate annual and seasonal patterns of nitrate losses in streamflow and baseflow from the Raccoon River. Combining hydrograph separation with a load estimation program, we estimated that baseflow contributes approximately two-thirds (17.3 kg/ha) of the mean annual nitrate export (26.1 kg/ha). Baseflow transport was greatest in spring and late fall when baseflow contributed more than 80% of the total export. Herein we propose a ‘baseflow enrichment ratio’ (BER) to describe the relation of baseflow water with baseflow nitrate loads. The long-term ratio of 1.23 for the Raccoon River suggests preferential leaching of nitrate to baseflow. Seasonal patterns of the BER identified the strong link between the baseflow nitrate loads and seasonal crop nitrogen requirements. Study results demonstrate the utility of assessing the baseflow contribution to nitrate loads to identify appropriate control strategies for reducing baseflow delivery of nitrate.
This research introduces GeospatialVR, an open-source collaborative virtual reality framework to dynamically create 3D real-world environments that can be served on any web platform and accessed via ...desktop and mobile devices and virtual reality headsets. The framework can generate realistic simulations of desired locations entailing the terrain, elevation model, infrastructures, dynamic visualizations (e.g. water and fire simulation), and information layers (e.g. disaster damages and extent, sensor readings, occupancy, traffic, weather). These layers enable in-situ visualization of useful data to aid public, scientists, officials, and decision-makers in acquiring a bird's eye view of the current, historical, or forecasted condition of a community. The framework incorporates multiuser support to allow different stakeholders to remotely work on the same VR environment and observe other users' actions and 3D positions via avatars in real-time, and thus, presenting the potential to be utilized as a virtual incident command center or a meeting room. GeospatialVR's purpose is to enhance existing web-based cyberinfrastructure systems with the integration of immersive geospatial capabilities to assist the development of next-generation information and decision support systems powered by virtual reality. Finally, several case studies have been developed for flooding, wildfire, transportation, and public safety.
•Open-source virtual reality framework to dynamically simulate any location in the world.•Development of a JavaScript API to serve and manage VR scenes on any web platform.•Support for real-time multiuser interaction with personalized avatars.•Use cases for flooding, wildfire, transportation, and law enforcement.
A Peculiar People Schwieder, Elmer; Schwieder, Dorothy; Morain, Tom
04/2009
eBook
Now back in print with a new essay, this classic of Iowa history focuses on the Old Order Amish Mennonites, the state's most distinctive religious minority. Sociologist Elmer Schwieder and historian ...Dorothy Schwieder began their research with the largest group of Old Order Amish in the state, the community near Kalona in Johnson and Washington counties, in April 1970; they extended their studies and friendships in later years to other Old Order settlements as well as the slightly less conservative Beachy Amish.A Peculiar Peopleexplores the origin and growth of the Old Order Amish in Iowa, their religious practices, economic organization, family life, the formation of new communities, and the vital issue of education. Included also are appendixes giving the 1967 "Act Relating to Compulsory School Attendance and Educational Standards"; a sample "Church Organization Financial Agreement," demonstrating the group's unusual but advantageous mutual financial system; and the 1632Dortrecht Confession of Faith, whose eighteen articles cover all the basic religious tenets of the Old Order Amish.Thomas Morain's new essay describes external and internal issues for the Iowa Amish from the 1970s to today. The growth of utopian Amish communities across the nation, changes in occupation (althoughThe Amish Directorystill lists buggy shop operators, wheelwrights, and one lone horse dentist), the current state of education and health care, and the conscious balance between modern and traditional ways are reflected in an essay that describes how the Old Order dedication toGelassenheit-the yielding of self to the interests of the larger community-has served its members well into the twenty-first century.
The goal of this study was to understand better the co-play of intrinsic soil properties and extrinsic factors of climate and management in the estimation of saturated hydraulic conductivity (Ksat) ...in intensively managed landscapes. For this purpose, a physically-based, modeling framework was developed using hydro-pedotransfer functions (PTFs) and watershed models integrated with Geographic Information System (GIS) modules. The integrated models were then used to develop Ksat maps for the Clear Creek, Iowa watershed and the state of Iowa. Four types of saturated hydraulic conductivity were considered, namely the baseline (Kb), the bare (Kbr), the effective with no-rain (Ke-nr) and the effective (Ke) in order to evaluate how management and seasonality affect Ksat spatiotemporal variability. Kb is dictated by soil texture and bulk density, whereas Kbr, Ke-nr, and Ke are driven by extrinsic factors, which vary on an event to seasonal time scale, such as vegetation cover, land use, management practices, and precipitation. Two seasons were selected to demonstrate Ksat dynamics in the Clear Creek watershed, IA and the state of Iowa; specifically, the months of October and April that corresponded to the before harvesting and before planting conditions, respectively.
Statistical analysis of the Clear Creek data showed that intrinsic soil properties incorporated in Kb do not reflect the degree of soil surface disturbance due to tillage and raindrop impact. Additionally, vegetation cover affected the infiltration rate. It was found that the use of Kb instead of Ke in water balance studies can lead to an overestimation of the amount of water infiltrated in agricultural watersheds by a factor of two. Therefore, we suggest herein that Ke is both the most dynamic and representative saturated hydraulic conductivity for intensively managed landscapes because it accounts for the contributions of land cover and management, local hydropedology and climate condition, which all affect the soil porosity and structure and hence, Ksat.
•Ksat varies spatially due to intrinsic soil properties.•Ksat varies temporally due to extrinsic factors of management and climate.•A physically based framework was developed with PTFs, watershed models, and GIS.•Ke is the most dynamic and representative Ksat for intensively managed landscapes.
Flood hydrologic response is influenced by rainfall structure (i.e., variability in space and time). How this structure shapes flood frequency is unknown, and flood frequency analyses typically ...neglect or simplify potentially important aspects of rainfall variability. This study seeks to understand how rainfall structure impacts flood frequency. We use stochastic storm transposition combined with a 15‐year record of hourly, 4‐km2 radar rainfall to generate 10,000 synthetic extreme rain events. These events are resampled into four “scenarios” with differing spatial and temporal resolutions, which are used as input to a distributed hydrologic model. Analysis of variance is used to identify the proportions of total flood peak variability attributable to spatial and to temporal rainfall variability under two antecedent soil moisture conditions. We simulate peak discharges for recurrence intervals of 2 to 500 years for 1,343 subwatersheds ranging in size from 16 to 4,400 km2 in Turkey River in the Midwestern United States, which is situated in a typically humid continental climactic region. Antecedent soil moisture modulates the role of rainfall structure in simulated flood response, particularly for more frequent events and large watershed scales. Rainfall spatial structure is more important than temporal structure for drainage areas larger than approximately 2,000 km2 (approximately 200 km2) for wet (dry) initial soil conditions, especially when soils are dry, while the reverse is true for smaller subwatersheds. The results appear to be related to the differing propensities for surface and subsurface runoff production as a function of basin scale, event magnitude, and soil saturation. Our results suggest that hydrologic model‐based flood frequency analyses, and particularly efforts attempting to spanning a range of scales, must carefully consider rainfall structure.
Plain Language Summary
There is increasing interest in “derived flood frequency analysis”: the use of stochastically generated rainfall and high‐resolution distributed hydrologic models to understand current and future flood frequency. Potential issues surrounding rainfall structure, resolution, and accuracy in this context have received very little attention, however. Design storm methods, common in hydrologic engineering practice, use highly idealized assumptions regarding rainfall space‐time structure, and the consequences of these assumptions are poorly understood. This study seeks to better understand how flood frequency is affected by rainfall spatial and temporal structure, as well as how these effects are modulated by watershed initial conditions (i.e., antecedent soil moisture). The findings, which are summarized in the manuscript's , should be useful for future researchers and practitioners. We believe that this work constitutes a useful contribution in the effort to advance the derived flood frequency analysis.
Key Points
Framework for partitioning impacts of rainfall spatial and temporal variability on flood frequency
The impact of rainfall structure varies significantly with antecedent soil moisture, watershed scale, and event magnitude
Rainfall temporal variability is more important than spatial variability at small scales; the opposite is true at large scales
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