Open Access. Powered by Scholars. Published by Universities.®

Life Sciences Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 15 of 15

Full-Text Articles in Life Sciences

Comparison Of Cellulosic Ethanol Yields From Midwestern Maize And Reconstructed Tallgrass Prairie Systems Managed For Bioenergy, V. A. Nichols, F. E. Miguez, M. E. Jarchow, M. Z. Liebman, B. S. Dien Dec 2014

Comparison Of Cellulosic Ethanol Yields From Midwestern Maize And Reconstructed Tallgrass Prairie Systems Managed For Bioenergy, V. A. Nichols, F. E. Miguez, M. E. Jarchow, M. Z. Liebman, B. S. Dien

Agronomy Publications

Maize- and prairie-based systems were investigated as cellulosic feedstocks by conducting a 9 ha side-by-side comparison on fertile soils in the Midwestern United States. Maize was grown continuously with adequate fertilization over years both with and without a winter rye cover crop, and the 31-species reconstructed prairie was grown with and without spring nitrogen fertilization. Both maize stover and prairie biomass were harvested in the fall. We compared amounts of cellulosic biomass produced and harvested, carbohydrate contents as measured by both dietary and detergent methods, and estimated cellulosic ethanol yields per hectare. From 2009–2013, the cropping system with the ...


Switchgrass Response To Nitrogen Fertilizer Across Diverse Environments In The Usa: A Regional Feedstock Partnership Report, C. O. Hong, V. N. Owens, D. Bransby, R. Farris, J. Fike, E. Heaton, S. Kim, H. Mayton, R. Mitchell, D. Viands Sep 2014

Switchgrass Response To Nitrogen Fertilizer Across Diverse Environments In The Usa: A Regional Feedstock Partnership Report, C. O. Hong, V. N. Owens, D. Bransby, R. Farris, J. Fike, E. Heaton, S. Kim, H. Mayton, R. Mitchell, D. Viands

Agronomy Publications

The Regional Feedstock Partnership is a collaborative effort between the Sun Grant Initiative (through Land Grant Universities), the US Department of Energy, and the US Department of Agriculture. One segment of this partnership is the field-scale evaluation of switchgrass (Panicum virgatum L.) in diverse sites across the USA. Switchgrass was planted (11.2 kg PLS ha−1 ) in replicated plots in New York, Oklahoma, South Dakota, and Virginia in 2008 and in Iowa in 2009. Adapted switchgrass cultivars were selected for each location and baseline soil samples collected before planting. Nitrogen fertilizer (0, 56, and 112 kg N ha−1 ...


2014 North Central Regional Conference, C. Lee Burras Aug 2014

2014 North Central Regional Conference, C. Lee Burras

Agronomy Publications

Seventy-six pedologists and related professionals registered to learn about--and contribute to-- the topics of soil survey, soil health, and soil dynamic properties at the 2014 North Central Regional Cooperative Soil survey Conference, held June 2nd through 5th on the campus of Iowa State University. Forty-four of the registrants were USDA--NRCS employees (14 from Iowa, 2 from regional and MLRA offices, and 8 from national postings), and 24 were university employees (7 faculty from ISU, 9 faculty from cooperating universities, and 8 graduate students). The remaining eight registrants were with cooperating agencies from Iowa, Minnesota, or the Federal government. The meeting ...


Significant Variation For Bio-Oil Compounds After Pyrolysis/Gas Chromatography–Mass Spectrometry Of Cobs And Stover Among Five Near-Isogenic Brown Midrib Hybrids In Maize, Brandon Jeffrey, Dan Nettleton, Najeeb Kuzhiyil, Marjorie Rover, Robert C. Brown, Kendall Lamkey, Thomas Lubberstedt Jun 2014

Significant Variation For Bio-Oil Compounds After Pyrolysis/Gas Chromatography–Mass Spectrometry Of Cobs And Stover Among Five Near-Isogenic Brown Midrib Hybrids In Maize, Brandon Jeffrey, Dan Nettleton, Najeeb Kuzhiyil, Marjorie Rover, Robert C. Brown, Kendall Lamkey, Thomas Lubberstedt

Agronomy Publications

We analyzed five near-isogenic brown-midrib hybrids in maize via pyrolysis/gas chromatography-mass spectrometry (Py/GC-MS) in order to determine how differing lignin composition and structure impacts individual bio-oil compounds. Twenty six compounds were analyzed for differences among the five hybrids and between cob and stover materials. We found statistically significant differences for 9 compounds, when comparing the five hybrids, and 17 significant differences when comparing maize cobs with stover. Our data indicate that it may be possible to predict phenolic compounds within bio-oil based on cell wall lignin composition. The genetic variation observed in this study suggests that bio-oil quality ...


Climate Forecasts For Corn Producer Decision Making, Eugene S. Takle, Christopher J. Anderson, Jeffrey Andresen, James Angel, Roger Elmore, Benjamin M. Gramig, Patrick Guinan, Steven Hilberg, Doug Kluck, Raymond Massey, Dev Niyogi, Jeanne M. Schneider, Martha D. Shulski, Dennis Patrick Todey, Melissa Widhalm Mar 2014

Climate Forecasts For Corn Producer Decision Making, Eugene S. Takle, Christopher J. Anderson, Jeffrey Andresen, James Angel, Roger Elmore, Benjamin M. Gramig, Patrick Guinan, Steven Hilberg, Doug Kluck, Raymond Massey, Dev Niyogi, Jeanne M. Schneider, Martha D. Shulski, Dennis Patrick Todey, Melissa Widhalm

Agronomy Publications

Corn is the most widely grown crop in the Americas, with annual production in the United States of approximately 332 million metric tons. Improved climate forecasts, together with climate-related decision tools for corn producers based on these improved forecasts, could substantially reduce uncertainty and increase profitability for corn producers. The purpose of this paper is to acquaint climate information developers, climate information users, and climate researchers with an overview of weather conditions throughout the year that affect corn production as well as forecast content and timing needed by producers. The authors provide a graphic depicting the climate-informed decision cycle, which ...


Top-Ranked Priority Research Questions For Soil Science In The 21st Century, Julius B. Adewopo, Christine Vanzomeren, Rupesh K. Bhomia, Maya Almaraz, Allan R. Bacon, Emily Eggleston, Jonathan D. Judy, Ricky W. Lewis, Mary Lusk, Bradley Allen Miller, Colby Moorberg, Elizabeth Hodges Snyder, Mary Lee Tiedeman Feb 2014

Top-Ranked Priority Research Questions For Soil Science In The 21st Century, Julius B. Adewopo, Christine Vanzomeren, Rupesh K. Bhomia, Maya Almaraz, Allan R. Bacon, Emily Eggleston, Jonathan D. Judy, Ricky W. Lewis, Mary Lusk, Bradley Allen Miller, Colby Moorberg, Elizabeth Hodges Snyder, Mary Lee Tiedeman

Agronomy Publications

Soils provide critical support essential for life on earth, regulate processes across diverse terrestrial and aquatic ecosystems, and interact with the atmosphere. However, soil science is constrained by a variety of challenges including decreasing funding prospects and a declining number of new students and young professionals. Hence, there is a crucial need to revitalize the impact, relevance, and recognition of soil science as well as promote collaboration beyond traditionally defined soil science research disciplines. Such revitalization and collaboration may be fostered by a shift from discipline-focused soil science research to cross-disciplinary research approaches and issue-driven research. In this paper, we ...


Sensible Heat Balance Measurements Of Soil Water Evaporation Beneath A Maize Canopy, X. Xiao, J. L. Heitman, T. J. Sauer, T. Ren, Robert Horton Jan 2014

Sensible Heat Balance Measurements Of Soil Water Evaporation Beneath A Maize Canopy, X. Xiao, J. L. Heitman, T. J. Sauer, T. Ren, Robert Horton

Agronomy Publications

Soil water evaporation is an important component of the water budget in cropped fields; few methods are available for continuous and independent measurement. A sensible heat balance (SHB) approach has been demonstrated for continuously determining soil water evaporation under bare surface conditions. Applicability of SHB measurements beneath a crop canopy cover has not been evaluated. We tested SHB using heat-pulse sensors to estimate evaporation beneath a full maize (Zea mays L.) canopy. We also implemented a modified SHB approach incorporating below-canopy net radiation, which extended the range of conditions under which SHB is applicable. Evaporation was measured at three positions ...


Field Test And Sensitivity Analysis Of A Sensible Heat Balance Method To Determine Soil Ice Contents, Yuki Kojima, Joshua L. Heitman, Gerald N. Glerchinger, Tusheng Ren, Robert P. Ewing, Robert Horton Jan 2014

Field Test And Sensitivity Analysis Of A Sensible Heat Balance Method To Determine Soil Ice Contents, Yuki Kojima, Joshua L. Heitman, Gerald N. Glerchinger, Tusheng Ren, Robert P. Ewing, Robert Horton

Agronomy Publications

Feasibility of the sensible heat balance (SHB) method for determining in situ soil ice content with heat pulse (HP) sensors was evaluated using field measurements. The required accuracy of HP sensor measurements for SHB was further assessed with a sensitivity analysis. Improving accuracy of thermal conductivity measurements and using short time steps are necessary to accurately estimate ice contents with the SHB method.

Soil ice content impacts winter vadose zone hydrology. It may be possible to estimate changes in soil ice content with a sensible heat balance (SHB) method, using measurements from heat pulse (HP) sensors. Feasibility of the SHB ...


Measurement Of Soil Water Content With Dielectric Dispersion Frequency, Jinghui Xu, Sally D. Logsdon, Xiaoyi Ma, Robert Horton, Wenting Han, Ying Zhao Jan 2014

Measurement Of Soil Water Content With Dielectric Dispersion Frequency, Jinghui Xu, Sally D. Logsdon, Xiaoyi Ma, Robert Horton, Wenting Han, Ying Zhao

Agronomy Publications

Frequency domain reflectometry (FDR) is an inexpensive and attractive methodology for repeated measurements of soil water content (θ). Although there are some known measurement limitations for dry soil and sand, a fixed-frequency method is commonly used with commercially available FDR probes. The purpose of our study was to determine if the soil dielectric spectrum could be used to measure changes in θ. A multifrequency FDR probe was constructed with a 6-mm diameter, and a soil dielectric spectrum was obtained. Using the dielectric spectrum, the dielectric dispersion frequency (fd) was determined. It was discovered that changes in fd were ...


Spatial And Temporal Dynamics Of Soil-Surface Carbon Dioxide Emissions In Bioenergy Corn Rotations And Reconstructed Prairies, Aaron L. Daigh, Thomas J. Sauer, Xinhua Xiao, Robert Horton Jan 2014

Spatial And Temporal Dynamics Of Soil-Surface Carbon Dioxide Emissions In Bioenergy Corn Rotations And Reconstructed Prairies, Aaron L. Daigh, Thomas J. Sauer, Xinhua Xiao, Robert Horton

Agronomy Publications

The interest in bioenergy crops has raised questions as to the potential of management strategies to preserve soil C pools and soil quality. Since soil-surface CO2 effluxes are a major fate of soil C, knowledge of CO2 efflux’s spatial and temporal trends among bioenergy crops will facilitate advances in research on improving terrestrial C-cycle models as well as decision support tools for policy and land-management. Our objective was to evaluate spatial and temporal dynamics of soil-surface CO2 effluxes in bioenergy-based corn (Zea mays L.) and reconstructed prairie systems. Systems evaluated included continuous corn (harvested for grain ...


Time Domain Reflectometry Waveform Analysis With Second-Order Bounded Mean Oscillation, Zhuangji Wang, Yuki Kojima, Songtao Lu, Yan Chen, Robert Horton, Robert C. Schwartz Jan 2014

Time Domain Reflectometry Waveform Analysis With Second-Order Bounded Mean Oscillation, Zhuangji Wang, Yuki Kojima, Songtao Lu, Yan Chen, Robert Horton, Robert C. Schwartz

Agronomy Publications

Tangent-line methods and adaptive waveform interpretation with Gaussian filtering (AWIGF) have been proposed for determining reflection positions of time domain reflectometry (TDR) waveforms. However, the accuracy of those methods is limited for short-probe TDR sensors. Second-order bounded mean oscillation (BMO) may be an alternative method to determine reflection positions of short-probe TDR waveforms. For this study, an algorithm of second-order BMO is developed. Example waveforms are analyzed with tangent-line methods, AWIGF method, and second-order BMO to illustrate the difference among the three methods. For some waveforms, second-order BMO appears be able to give more plausible results. Automatic implementation was challenging ...


Evolution Of Soil Carbon Storage And Morphometric Properties Of Afforested Soils In The U.S. Great Plains, Yuri G. Chendev, Larisa L. Novykh, Thomas J. Sauer, Aleksandr N. Petin, Evgeny A. Zazdravnykh, C. Lee Burras Jan 2014

Evolution Of Soil Carbon Storage And Morphometric Properties Of Afforested Soils In The U.S. Great Plains, Yuri G. Chendev, Larisa L. Novykh, Thomas J. Sauer, Aleksandr N. Petin, Evgeny A. Zazdravnykh, C. Lee Burras

Agronomy Publications

The objective of this project was to use detailed soil profi le descriptions and soil carbon analyses to determine the soil C sequestration potential of tree planting across climatic gradients in the U.S. Great Plains. Tree windbreak age ranged from 19 to 70 years and age of cultivation from 22 to ~110 years. At each site, soil pits were prepared within the tree planting, the adjacent crop fi elds, and nearby undisturbed grassland. Windbreak soils had consistently thicker soil organic carbon (SOC)- enriched A or A+AB horizons when compared to the crop fi elds. The thickness of A ...


Midwest Vision For Sustainable Fuel Production, Kenneth J. Moore, Stuart J. Birrell, Robert C. Brown, Michael D. Caster, Jill E. Euken, H. Mark Hanna, Dermot J. Hayes, Jason D. Hill, Keri L. Jacobs, Catherine L. Kling, David A. Laird, Robert B. Mitchell, Patrick T. Murphy, D. Raj Raman, Charles V. Schwab, Kevin J. Shinners, Kenneth P. Vogel, Jeffrey J. Volenic Jan 2014

Midwest Vision For Sustainable Fuel Production, Kenneth J. Moore, Stuart J. Birrell, Robert C. Brown, Michael D. Caster, Jill E. Euken, H. Mark Hanna, Dermot J. Hayes, Jason D. Hill, Keri L. Jacobs, Catherine L. Kling, David A. Laird, Robert B. Mitchell, Patrick T. Murphy, D. Raj Raman, Charles V. Schwab, Kevin J. Shinners, Kenneth P. Vogel, Jeffrey J. Volenic

Agronomy Publications

This article charts the progress of CenUSA Bioenergy, a USDA-NIFA-AFRI coordinated agricultural project focused on the North Central region of the US. CenUSA’s vision is to develop a regional system for producing fuels and other products from perennial grass crops grown on marginally productive land or land that is otherwise unsuitable for annual cropping. This article focuses on contributions CenUSA has made to nine primary systems needed to make this vision a reality: feedstock improvement; feedstock production on marginal land; feedstock logistics; modeling system performance; feedstock conversion into biofuels and other products; marketing; health and safety; education, and outreach ...


Agriculture, Jerry Hatfield, Eugene Takle, Richard Grotjahn, Patrick Holden, R. César Izaurralde, Terry Mader, Elizabeth Marshall, Diana Liverman Jan 2014

Agriculture, Jerry Hatfield, Eugene Takle, Richard Grotjahn, Patrick Holden, R. César Izaurralde, Terry Mader, Elizabeth Marshall, Diana Liverman

Agronomy Publications

No abstract provided.


Future Prospects For Corn As A Biofuel Crop, Kenneth J. Moore, Douglas L. Karlen, Kendall R. Lamkey Jan 2014

Future Prospects For Corn As A Biofuel Crop, Kenneth J. Moore, Douglas L. Karlen, Kendall R. Lamkey

Agronomy Publications

Ethanol production from corn grain has increased signifi cantly during the past ten years in the US. This increase was driven by government policy guided by the Renewable Fuel Standard (RFS) and embodied in the Volumetric Ethanol Excise Tax Credit and other legislation created to promote a biofuels industry. As corn grain ethanol production approaches the target set out in the RFS, the industry is looking to develop capacity for producing advanced biofuels, primarily from agricultural wastes and dedicated energy crops. The residues remaining following corn harvest have been identifi ed as a voluminous and readily available feedstock for advanced ...