Perennial Biomass Crop Establishment, Community Characteristics, And Productivity In The Upper Us Midwest: Effects Of Cropping Systems Seed Mixtures And Biochar Applications, 2018 Iowa State University
Perennial Biomass Crop Establishment, Community Characteristics, And Productivity In The Upper Us Midwest: Effects Of Cropping Systems Seed Mixtures And Biochar Applications, Catherine L. Bonin, Rivka B. Fidel, Chumki Banik, David A. Laird, Robert Mitchell, Emily A. Heaton
Native perennial plants have potential as bioenergy feedstocks, but their use is currently limited by relatively long establishment times and low biomass yields. Some research suggests that incorporating plant species diversity and applying biochar as a soil amendment might alleviate these limitations by creating a more resilient crop and soil system. The objective of this research was to investigate how 1) seeded plant diversity and 2) biochar soil amendments interact to affect the establishment, yield, and plant species composition of biomass cropping systems during the first four years of growth on productive soils. We measured species emergence, cover, peak and ...
Spatial Structuring Of Cellulase Gene Abundance And Activity In Soil, 2018 Iowa State University
Spatial Structuring Of Cellulase Gene Abundance And Activity In Soil, Jinlyung Choi, Elizabeth Bach, Jaejin Lee, Jared Flater, Shane Dooley, Adina Howe, Kirsten S. Hofmockel
Agricultural and Biosystems Engineering Publications
Microbial mechanisms controlling cellulose degradation in soil habitats remains a critical knowledge gap in understanding and modeling terrestrial carbon-cycling. We investigated land management and soil micro-habitat influences on soil bacterial communities and distribution of cellulose-degrading enzyme genes in three bioenergy cropping systems (corn, prairie, and fertilized prairie). Within the soil, aggregates have been examined as potential micro- habitats with specific characteristics influencing resource partitioning and regulation, thus we also investigated genes associated with cellulose degradation within soil aggregate fractions from the fertilized prairie system. Soil bacterial communities and carbon-cycling gene presence varied across land management and soil microhabitats. Examination of ...
Legacy Effects Of Long-Term Nitrogen Fertilizer Application On The Fate Of Nitrogen Fertilizer Inputs In Continuous Maize, Hanna J. Poffenbarger, John E. Sawyer, Daniel W. Barker, Daniel C. Olk, Johan Six, Michael J. Castellano
Nitrogen fertilizer management can impact soil organic C (SOC) stocks in cereal-based cropping systems by regulating crop residue inputs and decomposition rates. However, the impact of long-term N fertilizer management, and associated changes in SOC quantity and quality, on the fate of N fertilizer inputs is uncertain. Using two 15-year N fertilizer rate experiments on continuous maize (Zea mays L.) in Iowa, which have generated gradients of SOC, we evaluated the legacy effects of N fertilizer inputs on the fate of added N. Across the historical N fertilizer rates, which ranged from 0 to 269 kg N ha−1 yr ...
Conservation Agriculture Practices Increase Potentially Mineralizable Nitrogen: A Meta-Analysis, 2018 Iowa State University
Conservation Agriculture Practices Increase Potentially Mineralizable Nitrogen: A Meta-Analysis, Navreet K. Mahal, Michael J. Castellano, Fernando E. Miguez
Potentially mineralizable nitrogen (PMN) is considered an important indicator of soil health. Cropping systems management can affect PMN. However, the effect size and relationship with crop yield across specific management practices remain uncertain. We conducted a quantitative review to understand how conservation agriculture management practices affect PMN including N fertilizer application, cropping system diversity, and tillage system as well as the relationship of crop yield with PMN. Data were extracted from 43 studies published in peer-reviewed journals, providing 494 paired comparisons of PMN and 26 paired comparisons of PMN and yield across selected crop management practices. In our meta-analysis, the ...
County-Wide Assessment Of Irrigation Expansion On Air Temperature, Humidity And Evapotranspiration Rates In Nebraska, 1979-2015, 2018 Conservation and Survey Division, School of Natural Resources
County-Wide Assessment Of Irrigation Expansion On Air Temperature, Humidity And Evapotranspiration Rates In Nebraska, 1979-2015, Jozsef Szilagyi
Conservation and Survey Division
Total irrigated land area has been expanding in Nebraska over the last 40 years, propelling the state into a leading position within the US in terms of irrigated acreages. Typically, those counties which display the largest degree of irrigation development had a significant portion of their land area already irrigated in 1978. Large-scale irrigation in Nebraska affects its atmospheric environment. During the typical irrigation season of May to August, counties with the largest rate of irrigation expansion have cooled by about 0.2 – 0.3 °F per decade in the summer months of June, July and August, while counties with ...
Pedology At Four Representative Sites Of Southern Highland Zone Of Tanzania, 2018 Tanzania Agricultural Research Institute: TARI
Pedology At Four Representative Sites Of Southern Highland Zone Of Tanzania, Johnson Godlove Mtama, Balthazar Michael Msanya, Charles Lee Burras
To study the soils of Southern Highland Zone of Tanzania, four representative pedons of some landscapes were characterized. Their names and identifiers are Seatondale, Mbimba, Inyala, and Uyole, respectively TzSea 01, TzMb 02, TzIny 03, and TzUy04. The pedons were formed from the weathering of among other materials, colluvial igneous rocks, alluvium, eluvial soils, laterite, lacustrine sands and silts, andesite, pumice, aeolian deposits, and metamorphic rocks including coarse grained and strongly foliated biotite gneisses. Twenty soil samples were taken for laboratory characterization. In addition to classical horizon by horizon descriptions and laboratory analyses, 12 core samples were taken for soil-water ...
Development And Application Of The Heat Pulse Method For Soil Physical Measurements, 2018 Northwest A&F University
Development And Application Of The Heat Pulse Method For Soil Physical Measurements, Hailong He, Miles F. Dyck, Robert Horton, Tusheng Ren, Keith L. Bristow, Jialong Lv, Bingcheng Si
Accurate and continuous measurements of soil thermal and hydraulic propertiesare required for environmental, Earth and planetary science, and engineering applications, but they are not practicallyobtained by steady-state methods. The heat pulse (HP) method is a transient method for determinationof soil thermal properties and a wide range of other physical properties in laboratory and field conditions. The HP method is based on the line-heat source solution of the radial heat flow equation. This literature review begins with a discussion of the evolution of the HP method and related applications, followed by the principal theories, data interpretation methods and their differences. Important ...
The Effect Of Two Different Harvesting Methods On The Yield Of 'Topbunch' And 'Hi-Crop' Collards (Brassica Oleracea (L)) When Grown In A Wiregrass Tunnel House, Veronica E. Walton, Raymon Shange, Melissa Johnson, Edward Sparks, Victor Khan, James E. Currington, Ramble Ankumah, Nathaniel Ellison, George X. Hunter Jr., Jeffery L. Moore
Professional Agricultural Workers Journal
A study was conducted to determine if 100% or 50% harvesting of collard leaves was a suitable recommendation for Tunnel House producers. The experiment was conducted as a split-split plot design with varieties as the main plots, harvesting 100% or 50% of leaves as the sub-plots, and days after transplanting as the subplots. All treatments were replicated three times, drip irrigated, and fertilized according to soil test recommendations. The results showed significant interactions between varieties and method of harvest, for leaf numbers and weight. Conversely, the varieties showed significant differences for yield but not leaf numbers. Both varieties showed significant ...
The Evaluation Of Two Different Harvesting 'Topbunch' And 'Hi-Crop' Collards (Brassica Oleracea (L)) Leaves From Plants Grown In A Wiregrass Tunnel House, Edward Sparks, Raymon Shange, Jacquelyn Jackson, Victor Khan, James E. Currington, Ramble Ankumah, Nathaniel Ellison, George X. Hunter Jr., Jeffery L. Moore
Professional Agricultural Workers Journal
A study was conducted to determine if a 100% or 50% harvest intensity of ‘Topbunch’ collards leaves could be a recommended practice for Tunnel House producers. The experiment was conducted as a split-plot design with harvest dates as main plots, and harvesting intensity of 100% or 50% of leaves as sub-plots. All treatments were replicated three times, drip irrigated, and fertilized according to soil test recommendations. The results showed significant interactions between harvest methods and dates for number and weight of leaves harvested. There were also significant differences for the weight of leaves harvested and numbers. The leaf recovery rates ...
Remote Sensing Using I-Band And S-Band Signals Of Opportunity, 2018 Purdue University
Remote Sensing Using I-Band And S-Band Signals Of Opportunity, Kadir Efecik, Benjamin R. Nold, James L. Garrison
The Summer Undergraduate Research Fellowship (SURF) Symposium
Measurement of soil moisture, especially the root zone soil moisture, is important in agriculture, meteorology, and hydrology. Root zone soil moisture is concerned with the first meter down the soil. Active and passive remote sensing methods used today utilizing L-band(1-2GHz) are physically limited to a sensing depth of about 5 cm or less. To remotely sense the soil moisture in the deeper parts of the soil, the frequency should be lowered. Lower frequencies cannot be used in active spaceborne instruments because of their need for larger antennas, radio frequency interference (RFI), and frequency spectrum allocations. Ground-based passive remote sensing ...
Spatial Response Of Near-Surface Soil Water Contents To Newly Imposed Soil Management, 2018 North Dakota State University--Fargo
Spatial Response Of Near-Surface Soil Water Contents To Newly Imposed Soil Management, Aaron L. M. Daigh, Upasana Ghosh, Jodi Dejong-Hughes, Robert Horton
Near-surface soil water content (SWC) and its spatial patterns are important for landscape hydrological responses to precipitation as well as our ability to remotely sense and model such responses. Our objective was to measure and evaluate near-surface SWC semivariograms of agricultural fields with newly imposed (i.e., <2 yr) side-by-side soil and residue management practices (i.e., reduced tillage systems and cover crops) in the midwestern United States. Range parameters were consistently smaller when cover crops were planted (20–25 m less) and tillage area and/or intensity was reduced (12–27 m less) compared with no cover crop and chisel plowing, respectively, except in a clayey Vertisol. Nugget and sill parameters did not have consistent trends across soil management practices or sites. These data, although brief and preliminary in scope, provide clear proof of concept that spatial pattern shifts can be clearly detected in newly imposed soil-management systems even though differences in SWC means are not always evident.
Geophysical Assessment Of Subsurface Soil Conditions Using Capacitively Coupled Resistivity, 2018 University of Arkansas, Fayetteville
Geophysical Assessment Of Subsurface Soil Conditions Using Capacitively Coupled Resistivity, Folaseye Coker
Theses and Dissertations
The purpose of this research is to explore the applicability of Capacitively-Coupled Resistivity (CCR) as an improvement on traditional drilling and sampling methods for subsurface soil investigations. The CCR method could be used to identify critical locations for drilling and sampling such as expansive clay layers and anomalies (sinkholes, unknown landfills, etc.) rather than uniformly sampling across a site. CCR surveys were performed at Alpena, Arkansas along a highway expansion project changing US 62 from a two lane to four lane highway, and at Alton, Illinois along the Mel Price Levee, a 5.2 mile levee along a portion of ...
Flow Regime Influences On Stream And Riparian Soil Carbon Dynamics In The Ozark Highlands And Boston Mountains Of Arkansas, 2018 University of Arkansas, Fayetteville
Flow Regime Influences On Stream And Riparian Soil Carbon Dynamics In The Ozark Highlands And Boston Mountains Of Arkansas, Allyn Dodd
Theses and Dissertations
The natural flow regime exerts primacy over lotic ecosystem patterns and processes. However, little work has examined the influence of flow regime on instream and riparian carbon (C) dynamics in minimally-impacted, temperate forested systems. To date, most research efforts have focused on characterizing C movement and transformations across biomes and land use categories; however, flow regime represents an overlooked, finer level of detail that may drive differences in ecosystem function. My dissertation objective was to measure C fixation and movement within and across multiple environmental spheres (e.g. within stream channels, between stream surfaces and the atmosphere, and from riparian ...
Proposed Astm Standard For The Stokoe-Type Resonant Column Torsional Shear Device, 2018 University of Arkansas, Fayetteville
Proposed Astm Standard For The Stokoe-Type Resonant Column Torsional Shear Device, Anh Tuan Tran
Theses and Dissertations
Resonant Column Torsional Shear (RCTS) testing has become one of the most commonly used methods for determining laboratory soil stiffness and soil damping. The RCTS test has been accepted and is commonly utilized during the permitting of new nuclear facilities. However, there is still no available public standard for performing RCTS tests using the Stokoe-type device. Therefore, an ASTM standard for calibration and performance of RCTS tests using the Stokoe-type RCTS device is presented herein. Data collected using the Stokoe-type RCTS devices at the University of Arkansas (UofA) and at the Norwegian Geotechnical Institute (NGI) also aided in the development ...
Approaches For Estimating Soil Water Retention Curves At Various Bulk Densities With The Extended Van Genuchten Model, 2018 North Carolina State University
Approaches For Estimating Soil Water Retention Curves At Various Bulk Densities With The Extended Van Genuchten Model, Zhengchao Tian, Weida Gao, Dilia Kool, Tusheng Ren, Robert Horton, Joshua L. Heitman
Soil bulk density (ρb) variations influence soil hydraulic properties, such as the water retention curve (WRC), but they are usually ignored in soil-water simulation models. We extend the van Genuchten WRC model parameters to account for ρb variations using a series of empirical expressions. WRC measurements made on eight soils with various ρb and textures are used to calibrate these ρb–related empirical equations. Accordingly, two approaches are developed to estimate WRCs of soils at various ρb. Another eight soils with a wide range of ρb and textures are used to evaluate the accuracy of the new approaches. Approach 1 ...
Summary Of Advances In The Heat-Pulse Technique: Improvements In Measuring Soil Thermal Properties, 2018 China Agricultural University
Summary Of Advances In The Heat-Pulse Technique: Improvements In Measuring Soil Thermal Properties, Minmin Wen, Gang Liu, Robert Horton, Yili Lu, Tusheng Ren
This essay provides a summary of “Advances in the Heat-Pulse Technique: Improvements in Measuring Soil Thermal Properties” recently appearing in Methods of Soil Analysis. Series.
Using Geological Facies To Estimate Chromate Sorption To Soils, 2018 Delaware State University
Using Geological Facies To Estimate Chromate Sorption To Soils, Victoria Smith, Daja Scurlock, Chauntilena Butler, Eddie Hollins, Kennedy Smith, Tim Spearman, Christina Fulghum, John Dickson, Daniel I. Kaplan, Miles Denham, Garriet Smith
Journal of the South Carolina Academy of Science
Quantifying the extent to which contaminant metals bind to subsurface soils is important for risk assessment, the tendency for a contaminant to migrate, and developing environmental remediation strategies. Unfortunately, subsurface soils vary widely in their composition, which in turn affect their tendency to bind metals. The hypothesis of this study was predicated on how a better understanding of geological facies would reduce uncertainty associated with predicting contaminant metal sorption. Facies are layers of sediment deposited in the subsurface due to similar depositional conditions, including energy of an overlying waterway. As such, facies are expected to have similar assemblages of minerals ...
Distribution Of Classified Soils In South-West Western Australia, 2018 Department of Agriculture and Food Western Australia
Distribution Of Classified Soils In South-West Western Australia, Dennis Van Gool, Angela Stuart-Street, Peter Tille
Resource management technical reports
This report provides areas, locations and properties of the main soil classifications identified in south-west Western Australia using current conventional soil map data. It is a reference point for classified soils in the south-west. It provides a way of communicating how soil properties or productivity are likely to relate to soils with similar classifications found elsewhere so that soil research or knowledge can be effectively shared around the state and across Australia.
This is a high-level summary of the relationships between the main soil classifications currently used in Western Australia. These are: • Western Australian Soil Groups, WASG (Schoknecht & Pathan 2013 ...
A Broad Spectrum Racemase In Pseudomonas Putida Kt2440 Plays A Key Role In Amino Acid Catabolism, 2018 University of California - San Francisco
A Broad Spectrum Racemase In Pseudomonas Putida Kt2440 Plays A Key Role In Amino Acid Catabolism, Atanas D. Radkov, Luke A. Moe
Plant and Soil Sciences Faculty Publications
The broad-spectrum amino acid racemase (Alr) of Pseudomonas putida KT2440 preferentially interconverts the L- and D-stereoisomers of Lys and Arg. Despite conservation of broad-spectrum racemases among bacteria, little is known regarding their physiological role. Here we explore potential functional roles for Alr in P. putida KT2440. We demonstrate through cellular fractionation that Alr enzymatic activity is found in the periplasm, consistent with its putative periplasm targeting sequence. Specific activity of Alr is highest during exponential growth, and this activity corresponds with an increased accumulation of D-Lys in the growth medium. An alr gene knockout strain (Δalr) was generated and ...
Soil Conservation Efforts Affecting And Implementations To Help Tree Growth In Iceland, 2018 Embry-Riddle Aeronautical University
Soil Conservation Efforts Affecting And Implementations To Help Tree Growth In Iceland, Justin Lawlor
The purpose of this research was to understand and project the opinions of the public in Iceland on soil conservation and current efforts. The issue of soil erosion dates back to settlement around 1,100 years ago. The loss of vegetation from deforestation and grazing exposes the land to the effects of wind, water, and other devastating elements, leading it to erode away. The Soil Conservation Service of Iceland (SCSI) was developed to combat this issue over 100 years ago with efforts including planting trees, promoting safe farming practices, and replenishing the land. Interviews were conducted with various individuals, including ...