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Living Seeds Of History: The John Stokes And Mary's Gardens Exhibit, Stephanie Shreffler, Kayla Harris Dec 2017

Living Seeds Of History: The John Stokes And Mary's Gardens Exhibit, Stephanie Shreffler, Kayla Harris

Kayla Harris

This panel describes how the University of Dayton planned and carried out an exhibit on the John Stokes and Mary’s Gardens archival collection, featuring a garden inside the library. A “Mary garden” is a garden filled with flowers named for Mary.

The panel describes the content of the collection and how the exhibit was originally conceived; the exhibit design and programming; and the challenges faced during the planning process.

The exhibit provided a way for the Libraries to promote an archival collection that not only closely connected with the University’s mission as a Catholic institution, but also provided new opportunities …


Quantifying The Benefits Of On-Farm Best Management Practices For Irrigation And Nutrient Management, I. Zaragoza, K. Post, L. Johnson, R. Spellenberg, S. Kortman, C. Rosevelt, G. Muro, D. Goorahoo, F. Cassel-Sharma, M. Cahn, A. Haffa, F. Melton Nov 2017

Quantifying The Benefits Of On-Farm Best Management Practices For Irrigation And Nutrient Management, I. Zaragoza, K. Post, L. Johnson, R. Spellenberg, S. Kortman, C. Rosevelt, G. Muro, D. Goorahoo, F. Cassel-Sharma, M. Cahn, A. Haffa, F. Melton

Arlene Haffa

With the implementation of the Irrigated Lands Regulatory Program (INRP) in 2012 and the Sustainable Groundwater Management Act (SGMA) in 2014, growers across California are under increased regulatory pressure to meet nitrogen fertilizer and water use objectives through documented, measureable outcomes. Growers need information on the benefits of using low-cost best management practices (BMPs) so that they can quantify and report benefits of on-farm BMPs as part of an integrated irrigation and nutrient management strategy. This project will focus on conducting research to quantify the benefits of on-farm BMPs, including evapotranspiration-based irrigation management and the use of nitrate quick tests …


Rice Grain Protein Composition Influences Instrumental Measures Of Rice Cooking And Eating Quality, Jeanette L. Balindong, Rachel M. Ward, Lei Liu, Terry J. Rose, Laura A. Pallas, Ben W. Ovenden, Peter J. Snell, Daniel Le Waters Oct 2017

Rice Grain Protein Composition Influences Instrumental Measures Of Rice Cooking And Eating Quality, Jeanette L. Balindong, Rachel M. Ward, Lei Liu, Terry J. Rose, Laura A. Pallas, Ben W. Ovenden, Peter J. Snell, Daniel Le Waters

Adjunct Associate Professor Daniel LE Waters

Rice cultivar starch composition differences do not completely explain variation in rice cooking and eating quality. Rice grain storage proteins possess divergent solubility properties suggesting they may contribute to cultivar differences in rice grain quality. Application of high-performance liquid chromatography (HPLC) analysis to protein extracts derived from medium and long grain advanced rice breeding lines revealed rice grain protein composition differences which were associated with instrumental measures of grain quality. Globulin content displayed little variation in both grain types. The mean glutelin content was higher in long grain rice lines than medium grains. Although the mean content of prolamins in …


Floristic Response To Urbanization: Filtering Of The Bioregional Flora In Indianapolis, Indiana, Usa, Rebecca W. Dolan, Myla F.J. Aronson, Andrew L. Hipp Sep 2017

Floristic Response To Urbanization: Filtering Of The Bioregional Flora In Indianapolis, Indiana, Usa, Rebecca W. Dolan, Myla F.J. Aronson, Andrew L. Hipp

Rebecca W. Dolan

PREMISE OF THE STUDY: Globally, urban plant populations are becoming increasingly important, as these plants play a vital role in ameliorating effects of ecosystem disturbance and climate change. Urban environments act as filters to bioregional flora, presenting survival challenges to spontaneous plants. Yet, because of the paucity of inventory data on plants in landscapes both before and after urbanization, few studies have directly investigated this effect of urbanization. METHODS: We used historical, contemporary, and regional plant species inventories for Indianapolis, Indiana USA to evaluate how urbanization filters the bioregional flora based on species diversity, functional traits, and phylogenetic community structure. …


Surface-Soil Properties Of Alder Balds With Respect To Grassy And Rhododendron Balds On Roan Mountain, North Carolina—Tennessee, James T. Donaldson, Zachary C. Dinkins, Foster Levy, Arpita Nandi Aug 2017

Surface-Soil Properties Of Alder Balds With Respect To Grassy And Rhododendron Balds On Roan Mountain, North Carolina—Tennessee, James T. Donaldson, Zachary C. Dinkins, Foster Levy, Arpita Nandi

Foster Levy

We analyzed soils in Alder Bald, Grassy Bald, and Rhododendron Bald communities on Roan Mountain to infer the influence of vegetation on soil and to help guide management strategies. In all vegetation types, soils were acid (pH = 4–5) sandy loams. We found vegetation-associated differences for organic content, cation exchange capacity, acidity, two plant macronutrients (K, Mg), and three cations (Fe, Na, Zn). We predicted that nitrogen compounds would be highest in the Alder Bald because Alnus viridis ssp. crispa (Green Alder) can harbor nitrogen-fixing bacteria. Organic content was highest at the alder-bald sites, ammonium was similar among vegetation types, …


Pattern And Rate Of Decline Of A Population Of Carolina Hemlock (Tsuga Caroliniana Engelm.) In North Carolina, Foster Levy, Elaine S. Walker Aug 2017

Pattern And Rate Of Decline Of A Population Of Carolina Hemlock (Tsuga Caroliniana Engelm.) In North Carolina, Foster Levy, Elaine S. Walker

Foster Levy

We monitored a population of Carolina Hemlocks in northwestern North Carolina for four years to examine the rate and pattern of decline in response to infestation by Adelges tsugae (Hemlock Woolly Adelgid). Our yearly census of hemlock condition and severity of the adelgid infestation included trees of all sizes. We estimated declines in condition as the portions of the leaf canopy that were lost. Initially, infestation occurred throughout the population but was severe in only a small cluster of individuals. Within 1 year, the area of severe infestation increased in size to encompass 48% of the population. In another region …


Supplemental Data, Russell J. Ingram, Foster Levy, Cindy L. Barrett, James T. Donaldson Aug 2017

Supplemental Data, Russell J. Ingram, Foster Levy, Cindy L. Barrett, James T. Donaldson

Foster Levy

No abstract provided.


Deidamia Inscriptum (Lettered Sphinx Moth) Caterpillars Feeding On Oxydendrum Arboreum (Sourwood) And Their Predation By Black Bears In Northeast Tennessee, Foster Levy, David L. Wagner, Elaine S. Walker Aug 2017

Deidamia Inscriptum (Lettered Sphinx Moth) Caterpillars Feeding On Oxydendrum Arboreum (Sourwood) And Their Predation By Black Bears In Northeast Tennessee, Foster Levy, David L. Wagner, Elaine S. Walker

Foster Levy

An outbreak of Deidamia inscriptum (Lettered Sphinx Moth) caterpillars was noted in northeast Tennessee where Oxydendrum arboreum (Sourwood) trees were defoliated. Nearly all published literature and online resources list only plants in the grape family (Vitaceae) as larval food plants. Food-plant preference trials using fresh leaves of 3 woody plant species showed that Deidamiacaterpillars from this region had a preference for Sourwood over Parthenocissus quinquefolia(Virginia Creeper), and rejected Acer rubrum (Red Maple), a non-host species. Ursus americanus(Black Bear) were feeding on the caterpillars as evidenced by bent and broken Sourwood saplings bearing claw marks and by abundant …


Applying Biodiversity And Ecosystem Function Theory To Turfgrass Management, Grant L. Thompson, Jenny Kao-Kniffin Aug 2017

Applying Biodiversity And Ecosystem Function Theory To Turfgrass Management, Grant L. Thompson, Jenny Kao-Kniffin

Grant Thompson

In the United States, there is a growing need for turfgrass management practices that protect community and environmental health. The proportion of the developed landscape in the United States covered by turfgrass is significant and, at present, covers at least 1.9% of the total land area and comprises 60% in parts of the country. As urbanization progresses, there is a critical need to re-examine turf management practices that reduce reliance on pesticide and fertilizer inputs while contributing additional beneficial ecosystem services. In this review, we discuss the functional role of turfgrass in urban ecosystems. We identify key urban ecosystem processes …


Conditional Vulnerability Of Plant Diversity To Atmospheric Nitrogen Deposition Across The United States, Samuel M. Simkin, Edith B. Allen, William D. Bowman, Christopher M. Clark, Jayne Belnap, Matthew L. Brooks, Brian S. Cade, Scott L. Collins, Linda H. Geiser, Frank S. Gilliam, Sarah E. Jovan, Linda H. Pardo, Bethany K. Schulz, Carly J. Stevens, Katharine N. Suding, Heather L. Throop, Donald M. Waller Aug 2017

Conditional Vulnerability Of Plant Diversity To Atmospheric Nitrogen Deposition Across The United States, Samuel M. Simkin, Edith B. Allen, William D. Bowman, Christopher M. Clark, Jayne Belnap, Matthew L. Brooks, Brian S. Cade, Scott L. Collins, Linda H. Geiser, Frank S. Gilliam, Sarah E. Jovan, Linda H. Pardo, Bethany K. Schulz, Carly J. Stevens, Katharine N. Suding, Heather L. Throop, Donald M. Waller

Frank S. Gilliam

Atmospheric nitrogen (N) deposition has been shown to decrease plant species richness along regional deposition gradients in Europe and in experimental manipulations. However, the general response of species richness to N deposition across different vegetation types, soil conditions, and climates remains largely unknown even though responses may be contingent on these environmental factors. We assessed the effect of N deposition on herbaceous richness for 15,136 forest, woodland, shrubland, and grassland sites across the continental United States, to address how edaphic and climatic conditions altered vulnerability to this stressor. In our dataset, with N deposition ranging from 1 to 19 kg …


Impact Of Nitrogen Application Timing On Corn Production, John E. Sawyer, Daniel W. Barker, John P. Lundvall Aug 2017

Impact Of Nitrogen Application Timing On Corn Production, John E. Sawyer, Daniel W. Barker, John P. Lundvall

John E. Sawyer

Water quality issues have renewed interest in timing of nitrogen (N) application as a means to improve use efficiency in corn and reduce losses. Improved economic return is also desired as N fertilization is one of the most costly inputs to corn production. Time of fertilizer application is a component of the site-specific 4R nutrient management stewardship programs. In Iowa, the Nutrient Reduction Strategy has a 7% (37% std. dev.) nitrate-N reduction with a 0% (3% std. dev.) corn yield change for sidedress compared to pre-plant N application (SP 0435A).


Crop Responses To Amisorb In The North Central Region, Sylvie Brouder, Robert Dowdy, Dave Franzen, Gary Hergert, Robert Hoeft, Maurice Horton, Keith Kelling, David Mengel, George Rehm, John Sawyer, Peter Scharf, Darryl Warnacke, David Whitney Aug 2017

Crop Responses To Amisorb In The North Central Region, Sylvie Brouder, Robert Dowdy, Dave Franzen, Gary Hergert, Robert Hoeft, Maurice Horton, Keith Kelling, David Mengel, George Rehm, John Sawyer, Peter Scharf, Darryl Warnacke, David Whitney

John E. Sawyer

Originally used to prevent scale in boilers, carpramid or thermal polyaspartate (copoly[(3-carboxypropionamide)( 2-carboxylmethyl) acetamide)] was brought to agriculture under the trade names AmiSorb and Magnet. It claimed to increase nutrient uptake through artificially increasing the volume of soil occupied by roots through increased root branching and root hair development. Under controlled hydroponic or greenhouse conditions, the use of carpramid increased nutrient uptake, some yield determining factors such as wheat tillering and in some cases, crop yield. Extensive field testing from 1996 to 1998 under various nutrient regimes, placements, forms, and timings resulted in very inconsistent performance. Averaged across all experiments …


Nitrogen Fertilizer Rate Effects On Soil Organic Carbon In Iowa Continuous Corn And Corn-Soybean Systems, Hanna J. Poffenbarger, Daniel W. Barker, Matthew J. Helmers, Fernando E. Miguez, John E. Sawyer, Johan Six, Michael J. Castellano Aug 2017

Nitrogen Fertilizer Rate Effects On Soil Organic Carbon In Iowa Continuous Corn And Corn-Soybean Systems, Hanna J. Poffenbarger, Daniel W. Barker, Matthew J. Helmers, Fernando E. Miguez, John E. Sawyer, Johan Six, Michael J. Castellano

John E. Sawyer

Nitrogen fertilizer rate is a key factor affecting soil organic C (SOC) in corn-based cropping systems. The objective of this study was to determine the change in SOC in response to long-term N rates for continuous corn and corn-soybean cropping systems at two sites in Iowa. Soil samples were collected to a depth of 15 cm in 1999 and again in 2014 after 15 years of corn N rate treatments ranging from 0 to 269 kg ha-1. The soil samples were analyzed for total C and N concentrations. For continuous corn at both sites, the average annual change …


Genomic Approaches For Improvement Of Understudied Grasses, Keenan Amundsen, Gautam Sarath, Teresa Donze-Reiner Jul 2017

Genomic Approaches For Improvement Of Understudied Grasses, Keenan Amundsen, Gautam Sarath, Teresa Donze-Reiner

Teresa Donze-Reiner

No abstract provided.


2017_Murphy Et Al._Food Habits Of A Small Fl Bear Population In Endangered Ecosystem.Pdf, Sean M. Murphy, Wade A. Ulrey, Joseph M. Guthrie, David S. Maehr, Warren G. Abrahamson Ii, Sutton C. Maehr, John J. Cox Jun 2017

2017_Murphy Et Al._Food Habits Of A Small Fl Bear Population In Endangered Ecosystem.Pdf, Sean M. Murphy, Wade A. Ulrey, Joseph M. Guthrie, David S. Maehr, Warren G. Abrahamson Ii, Sutton C. Maehr, John J. Cox

Warren G. Abrahamson, II

The Highlands–Glades subpopulation (HGS) of Florida, USA, black bears (Ursus americanus floridanus) is small, genetically depauperate, and resides primarily within the endangered Lake Wales Ridge ecosystem, which has lost >85% of native habitat to land development. Habitat loss can reduce availability of critical natural foods and cause bears to increase reliance on anthropogenic foods (i.e., human-sourced); lands supporting the HGS are expected to lose >50% of remaining Florida black bear habitat in coming decades. We used scat analysis to describe seasonal food habits, investigate potential dietary responses to food shortages, and inform habitat conservation and human–bear conflict management. …


A Smartphone-Based Device For Measuring Soil Organic Matter, Meng Lu Jun 2017

A Smartphone-Based Device For Measuring Soil Organic Matter, Meng Lu

Meng Lu

The project evaluated the potential of utilizing a smartphone-based system for the in-field analysis of Soil Organic Matter. Although it demonstrated that the performance of the smartphone-based spectrometer can be comparable to commercial spectrometers, the results suggest that it is challenging to identify the spectral “signatures” of the SOM due to the morphology and moisture variation of soil samples.


Winter Grazing Management, Stephen K. Barnhart, James R. Russell, Douglas L. Karlen, Michael J. Tidman Jun 2017

Winter Grazing Management, Stephen K. Barnhart, James R. Russell, Douglas L. Karlen, Michael J. Tidman

Douglas L Karlen

Why winter grazing? Beef cow herd and sheep flock records show that winter feeding costs are livestock producers' single largest production expense. Managing through winter weather while keeping feeding costs low is an essential part of maintaining a profitable operation. Iowa's climate generally allows forage growth only during a 7-to-8 month period. Extending the grazing of this forage--even an extra 3 or 4 weeks in late autumn and winter--is an economical way to maintain or increase livestock profitability. Some producers extend the grazing season by using stockpiled forage, whereas others use crop residue, and many combine the use of stockpiled …


Engineering, Nutrient Removal, And Feedstock Conversion Evaluations Of Four Corn Stover Harvest Scenarios, Reed L. Hoskinson, Douglas L. Karlen, Stuart J. Birrell, Corey W. Radtke, Wally Wilhelm Jun 2017

Engineering, Nutrient Removal, And Feedstock Conversion Evaluations Of Four Corn Stover Harvest Scenarios, Reed L. Hoskinson, Douglas L. Karlen, Stuart J. Birrell, Corey W. Radtke, Wally Wilhelm

Douglas L Karlen

Crop residue has been identified as a near-term source of biomass for renewable fuel, heat, power, chemicals and other bio-materials. A prototype one-pass harvest system was used to collect residue samples from a corn (Zea mays L.) field near Ames, IA. Four harvest scenarios (low cut, high-cut top, high-cut bottom, and normal cut) were evaluated and are expressed as collected stover harvest indices (CSHI). High-cut top and high-cut bottom samples were obtained from the same plot in separate operations. Chemical composition, dilute acid pretreatment response, ethanol conversion yield and efficiency, and thermochemical conversion for each scenario were determined. Mean …


Protocol For Indicator Scoring In The Soil Management Assessment Framework (Smaf), Brian J. Wienhold, D.L. Karlen, S.S. Andrews, D.E. Stott Jun 2017

Protocol For Indicator Scoring In The Soil Management Assessment Framework (Smaf), Brian J. Wienhold, D.L. Karlen, S.S. Andrews, D.E. Stott

Douglas L Karlen

Assessment tools are needed to evaluate agronomic management effects on critical soil functions such as carbon sequestration, nutrient cycling and water partitioning. These tools need to be flexible in terms of selection of soil functions to be assessed and indicators to be measured to ensure that assessments are appropriate for the management goals. The soil management assessment framework (SMAF) is being developed to meet this need. The SMAF uses soil physical, chemical and biological indicator data to assess management effects on soil function using a three-step process for (1) indicator selection, (2) indicator interpretation and (3) integration into an index. …


Review And Interpretation: Nitrogen Management Strategies To Reduce Nitrate Leaching In Tile-Drained Midwestern Soils, Dana L. Dinnes, Douglas L. Karlen, Dan B. Jaynes, Thomas C. Kaspar, Jerry L. Hatfield, Thomas S. Colvin, Cynthia A. Cambardella Jun 2017

Review And Interpretation: Nitrogen Management Strategies To Reduce Nitrate Leaching In Tile-Drained Midwestern Soils, Dana L. Dinnes, Douglas L. Karlen, Dan B. Jaynes, Thomas C. Kaspar, Jerry L. Hatfield, Thomas S. Colvin, Cynthia A. Cambardella

Douglas L Karlen

Balancing the amount of N needed for optimum plant growth while minimizing the NO3 that is transported to ground and surface waters remains a major challenge for everyone attempting to understand and improve agricultural nutrient use efficiency. Our objectives for this review are to examine how changes in agricultural management practices during the past century have affected N in Midwestern soils and to identify the types of research and management practices needed to reduce the potential for nonpoint NO3 leakage into water resources. Inherent soil characteristics and management practices contributing to nonpoint NO3 loss from Midwestern soils, the impact of …


Fluid Fertilizer’S Role In Sustaining Soils Used For Bio-Fuels Production, John L. Kovar, Douglas Karlen Jun 2017

Fluid Fertilizer’S Role In Sustaining Soils Used For Bio-Fuels Production, John L. Kovar, Douglas Karlen

Douglas L Karlen

The short- and long-term effects on soil nutrient cycling, physical properties, and biological activity of striving for higher grain yields and removing crop residues for bio-fuels production must be understood to provide more quantitative crop and soil management guidelines. This study focuses on potassium (K) and sulfur (S) requirements of corn (Zea mays L.) grown for bioenergy feedstock production. Our objectives for 2008 were to: i) evaluate the performance of several S fertilizers, including liquid ammonium thiosulfate (12-0-0-26S), as S sources for corn grown in Iowa, and ii) establish a comprehensive tillage, nutrient management, crop residue removal, and cover crop …


Winter Rye Cover Crop Biomass Production, Degradation, And N Recycling, J. L. Pantoja, J. E. Sawyer, D. W. Barker Apr 2017

Winter Rye Cover Crop Biomass Production, Degradation, And N Recycling, J. L. Pantoja, J. E. Sawyer, D. W. Barker

John E. Sawyer

Winter rye (Secale cereale L.) as a cover crop can take up residual inorganic N between annual row crops and therefore be used to help reduce NO3 -–N loss from fields and movement to water systems. However, does the rye N uptake affect N recycling to soil and add to plant available N? The rye carbon:nitrogen (C:N) ratio could also influence N recycling. The objectives of this study were to evaluate rye biomass degradation and N recycling after spring rye termination in a no-till corn (Zea mays L.) - soybean [Glycine max. (L.) Merr.] rotation. A two year experiment (2010-2011) …


In-Season Nitrogen Fertilization Of Soybean, J. E. Sawyer, D. W. Barker Apr 2017

In-Season Nitrogen Fertilization Of Soybean, J. E. Sawyer, D. W. Barker

John E. Sawyer

Nitrogen (N) fertilization is not a traditional nutrient management practice for soybean production in Iowa. Soybean is a legume plant and is assumed to adequately obtain needed N through symbiotic fixation. However, there has been interest over the years in using N fertilization to increase yield and grain protein due to the recognition of the large N requirement associated with high yields. Depending on the soil residual inorganic N level and soil N mineralization characteristics, approximately 40 to 75% of the N in a mature soybean plant is derived from the soil (Shibles, 1998). Also, soybean seems to require this …


Corn And Soybean Response To Sulfur Application On Iowa Soils, J. E. Sawyer, D. W. Barker Apr 2017

Corn And Soybean Response To Sulfur Application On Iowa Soils, J. E. Sawyer, D. W. Barker

John E. Sawyer

Historically sulfur (S) application has not been recommended on Iowa soils for com and soybean production. Prior research has not determined a consistent need for S fertilization in Iowa, with field research indicating no com or soybean yield response to applied S at virtually every site studied (Thorup and Leitch 1975; Webb, 1978; Alesii 1982; Killorn, 1984; Sexton et al., 1998; Mallarino et al., 2000). The soil supply, in combination with sources such as manure and atmospheric deposition has apparently met com and soybean S needs. Sulfur deficiencies have been reported over the years in various areas of the Midwestern …


Corn Nitrogen Rate Response And Crop Yield In A Rye Cover Crop System, John E. Sawyer, Jose L. Pantoja, Daniel W. Barker Apr 2017

Corn Nitrogen Rate Response And Crop Yield In A Rye Cover Crop System, John E. Sawyer, Jose L. Pantoja, Daniel W. Barker

John E. Sawyer

Water quality impairment related to N loss from crop production fields continues to be a concern in Iowa, including meeting the USEPA nitrate-N drinking water standard and reducing N export to the Gulf of Mexico. Therefore, in-field production practices would be helpful to aid in reduction of nitrate leaching and movement to water systems. One practice identified in the science assessment for the Iowa Nutrient Reduction Strategy is use of a winter cereal rye (Secale cereal L.) cover crop, where a mean 31% (29% standard deviation) nitrate-N reduction would be expected, but with a 6% (22% standard deviation) corn yield …


Dealing With Sulfur Deficiencies In Crop Production: The Iowa Experience, J. E. Sawyer, B. Lang, D. W. Barker, G. Cummins Apr 2017

Dealing With Sulfur Deficiencies In Crop Production: The Iowa Experience, J. E. Sawyer, B. Lang, D. W. Barker, G. Cummins

John E. Sawyer

Research conducted for more than forty years (prior to approximately 2005) in Iowa rarely noted improved crop yield with sulfur (S) fertilization. Studies during that time period with corn and soybean found yield increase from S fertilizer application only three times out of approximately 200 trials. Research in the early 1980’s had also documented sufficient plant available S in the soil profile for crop production on most Iowa soil associations. Results of recent studies (2000- 2005) in corn and soybean were consistent with the historical research. An example is research presented at this conference (Sawyer and Barker, 2002) where there …


Nutrient Management Plan, Antonio Mallarino, John Sawyer, Barbara Stewart, John Creswell Apr 2017

Nutrient Management Plan, Antonio Mallarino, John Sawyer, Barbara Stewart, John Creswell

John E. Sawyer

Management tools to help you develop a nutrient management plan and use the Iowa Phosphorus Index.


Nitrogen Application, John Sawyer, John Creswall Apr 2017

Nitrogen Application, John Sawyer, John Creswall

John E. Sawyer

Nitrogen (N) management planning for corn production.


Maximum Soil Organic Carbon Storage In Midwest U.S. Cropping Systems When Crops Are Optimally Nitrogen-Fertilized, Hanna J. Poffenbarger, Daniel W. Barker, Matthew J. Helmers, Fernando E. Miguez, Daniel C. Olk, John E. Sawyer, Johan Six, Michael J. Castellano Mar 2017

Maximum Soil Organic Carbon Storage In Midwest U.S. Cropping Systems When Crops Are Optimally Nitrogen-Fertilized, Hanna J. Poffenbarger, Daniel W. Barker, Matthew J. Helmers, Fernando E. Miguez, Daniel C. Olk, John E. Sawyer, Johan Six, Michael J. Castellano

John E. Sawyer

Nitrogen fertilization is critical to optimize short-term crop yield, but its long-term effect on soil organic C (SOC) is uncertain. Here, we clarify the impact of N fertilization on SOC in typical maize-based (Zea mays L.) Midwest U.S. cropping systems by accounting for site-to-site variability in maize yield response to N fertilization. Within continuous maize and maize-soybean [Glycine max (L.) Merr.] systems at four Iowa locations, we evaluated changes in surface SOC over 14 to 16 years across a range of N fertilizer rates empirically determined to be insufficient, optimum, or excessive for maximum maize yield. Soil organic C balances …


Seasonal And Rotational Influences On Corn Nitrogen Fertilization In Southwest Iowa, John Sawyer, Daniel Barker Mar 2017

Seasonal And Rotational Influences On Corn Nitrogen Fertilization In Southwest Iowa, John Sawyer, Daniel Barker

John E. Sawyer

This project was designed to study the nitrogen (N) fertilization needs in continuous corn (CC) and corn rotated with soybean (CS) as influenced by location and climate. Multiple rates of fertilizer N were spring applied, with the intent to measure yield response to N within each rotation on a yearly basis for multiple years at multiple sites across Iowa. This will allow determination of N requirements for each rotation, differences that exist between the two rotations, responses to applied N across different soils and climatic conditions, and evaluation of tools used to adjust N application.