Corn And Soybean Response To Sulfur Application On Iowa Soils,
2017
Iowa State University
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,
2017
Iowa State University
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,
2017
Iowa State University
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 …
Oxidation Of Substituted Catechols At The Air-Water Interface: Production Of Carboxylic Acids, Quinones, And Polyphenols,
2017
University of Kentucky
Oxidation Of Substituted Catechols At The Air-Water Interface: Production Of Carboxylic Acids, Quinones, And Polyphenols, Elizabeth A. Pillar, Marcelo I. Guzman
Chemistry Faculty Publications
Anthropogenic activities contribute benzene, toluene, and anisole to the environment, which in the atmosphere are converted into the respective phenols, cresols, and methoxyphenols by fast gas-phase reaction with hydroxyl radicals (HO(•)). Further processing of the latter species by HO(•) decreases their vapor pressure as a second hydroxyl group is incorporated to accelerate their oxidative aging at interfaces and in aqueous particles. This work shows how catechol, pyrogallol, 3-methylcatechol, 4-methylcatechol, and 3-methoxycatechol (all proxies for oxygenated aromatics derived from benzene, toluene, and anisole) react at the air-water interface with increasing O3(g) during τc ≈ 1 μs contact time and contrasts their …
Nutrient Management Plan,
2017
Iowa State University
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,
2017
Iowa State University
Nitrogen Application, John Sawyer, John Creswall
John E. Sawyer
Nitrogen (N) management planning for corn production.
Impact Of Fertilizer, Corn Residue, And Cover Crops On Mycorrhizal Inoculum Potential And Arbuscular Mycorrhizal Fungi Associations,
2017
University of Minnesota, Morris
Impact Of Fertilizer, Corn Residue, And Cover Crops On Mycorrhizal Inoculum Potential And Arbuscular Mycorrhizal Fungi Associations, Rachel Brockamp
Undergraduate Research Symposium 2017
Arbuscular Mycorrhizal Fungi (AMF) can associate with roots of most land plants, helping to take up water and nutrients. Intensive agricultural practices like fallow treatments and adding inorganic nutrients reduce soil AMF. The purpose of my research was to examine whether three factors influenced AMF-crop associations: 1) fertilizer type and application rate 2) inclusion of cover crops that do or do not associate with AMF, and 3) impacts of corn residue. Soil Mycorrhizal Inoculum Potential (MIP) was measured to test treatment differences. MIP is the ability for soil AMF to infect roots. Roots grown in soil from the different treatments …
Modeling Gross Primary Production Of Midwest Maize And Soybean Croplands With Satellite And Gridded Weather Data,
2017
University of Nebraska - Lincoln
Modeling Gross Primary Production Of Midwest Maize And Soybean Croplands With Satellite And Gridded Weather Data, Gunnar Malek-Madani
Department of Geography: Dissertations, Theses, and Student Research
The gross primary production (GPP) metric is useful in determining trends in the terrestrial carbon cycle. Models that determine GPP utilizing the light use efficiency (LUE) approach in conjunction with biophysical parameters that account for local weather conditions and crop specific factors are beneficial in that they combine the accuracy of the biophysical model with the versatility of the LUE model. One such model developed using in situ data was adapted to operate with remote sensing derived leaf area index (LAI) data and gridded weather datasets. The model, known as the Light Use Efficiency GPP Model (EGM), uses a four …
Emergence, Competition, And Management Of Glyphosate-Resistant Common Ragweed (Ambrosia Artemisiifolia L.) In Nebraska Soybean,
2017
University of Nebraska-Lincoln
Emergence, Competition, And Management Of Glyphosate-Resistant Common Ragweed (Ambrosia Artemisiifolia L.) In Nebraska Soybean, Ethann R. Barnes
Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research
Common ragweed (Ambrosia artemisiifolia L.) is a competitive annual broadleaf weed in soybean (Glycine max) production fields throughout North America. The recent confirmation of glyphosate-resistant common ragweed in Nebraska justified the need to assess the emergence pattern and competitive ability of common ragweed in soybean and to evaluate alternative herbicide programs for effective management. The objectives of this research were to: 1) evaluate the effect of tillage and develop a predictive model for the emergence pattern of common ragweed in Nebraska; 2) model the competitive interaction between soybean and common ragweed as influenced by density and irrigation …
Investigation De Regeneración Natural De Plantas Vasculares En La Reserva Madrigal Del Podocarpus / Investigation Of Natural Regeneration Of Vascular Plants In The Madrigal Reserve Of The Podocarpus,
2017
SIT Study Abroad
Investigation De Regeneración Natural De Plantas Vasculares En La Reserva Madrigal Del Podocarpus / Investigation Of Natural Regeneration Of Vascular Plants In The Madrigal Reserve Of The Podocarpus, Sy Baker
Independent Study Project (ISP) Collection
En el Sur de Ecuador, hay una historia larga de incendio que está asociada con la historia de la agricultura y ganadería a causa de las técnicas de tala y quema para despejar áreas para campos y también quemaduras intencionales para fertilizar los suelos y mejorar productividad agrícola (Fernandez et al 2015). En los últimos días de Noviembre de 2016, un incendio quemó campos, la Reserva Madrigal de Podocarpus, y parte del Parque Nacional Podocarpus en Loja, Ecuador—el enfoque de este estudio. En este estudio: (1) se registraron las especies y distribución de plantas pioneras y sobrevivientes, (2) la se …
Maximum Soil Organic Carbon Storage In Midwest U.S. Cropping Systems When Crops Are Optimally Nitrogen-Fertilized,
2017
Iowa State University
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 …
Corn Nitrogen Fertilization Requirement And Corn–Soybean Productivity With A Rye Cover Crop,
2017
Universidad de las Fuerzas Armadas Pichincha
Corn Nitrogen Fertilization Requirement And Corn–Soybean Productivity With A Rye Cover Crop, Jose L. Pantoja, Krishna P. Woli, John E. Sawyer, Daniel W. Barker
John E. Sawyer
Winter rye (Secale cereale L.) cover crop (RCC) has potential to reduce NO3–N loss from corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] fields. However, RCC effects on annual crop productivity and corn optimal N fertilization requirement are unclear. The objectives were to evaluate corn and soybean yield response to RCC and corn optimal N rate. Treatments were no-RCC and RCC with six fertilizer N rates (0–225 kg N ha-1) applied to corn in a no-till corn–soybean (CS) rotation at four Iowa sites in 2009 through 2011. The RCC biomass and …
Standardized Research Protocols Enable Transdisciplinary Research Of Climate Variation Impacts In Corn Production Systems,
2017
Purdue University
Standardized Research Protocols Enable Transdisciplinary Research Of Climate Variation Impacts In Corn Production Systems, E. J. Kladivko, M. J. Helmers, L. J. Abendroth, D. Herzmann, R. Lal, M. J. Castellano, D. S. Mueller, J. E. Sawyer, R. P. Anex, R. W. Arritt, B. Basso, J. V. Bonta, L. C. Bowling, R. M. Cruse, N. R. Fausey, J. R. Frankenberger, P. W. Gassman, A. J. Gassmann, C. L. Kling, A. Kravchenko, J. G. Lauer, F. E. Miguez, E. D. Nafziger, N. Nkongolo, M. O'Neal, L. B. Owens, P. R. Owens, P. Scharf, M. J. Shipitalo, J. S. Strock, M. B. Villamil
John E. Sawyer
The important questions about agriculture, climate, and sustainability have become increasingly complex and require a coordinated, multifaceted approach for developing new knowledge and understanding. A multistate, transdisciplinary project was begun in 2011 to study the potential for both mitigation and adaptation of corn-based cropping systems to climate variations. The team is measuring the baseline as well as change of the system's carbon (C), nitrogen (N), and water footprints, crop productivity, and pest pressure in response to existing and novel production practices. Nine states and 11 institutions are participating in the project, necessitating a well thought out approach to coordinating field …
Why Manage Phosphorus?,
2017
Iowa State University
Why Manage Phosphorus?, John E. Sawyer, Antonio P. Mallarino
John E. Sawyer
There are 17 nutrients that are essential for plant growth and production. An insufficient supply of one or more can have an adverse effect on plant growth, maturity, and yield. Phosphorus (P)--one of three key macronutrients (nitrogen and potassium are the other two)--is present in every living plant and animal cell, and is vital in plants for harvesting the sun's energy for growth and reproduction. This requirement is the same whether the plant is growing on soil or in water (such as algae); hence, the concern regarding P levels in surface water and the accelerated aquatic plant growth associated with …
Yellow Corn, Wet Soils, And Nitrogen Loss (Part 3),
2017
Iowa State University
Yellow Corn, Wet Soils, And Nitrogen Loss (Part 3), John E. Sawyer
John E. Sawyer
Earlier I provided observations in two articles (June 19 and June 26, 2008) on corn growth and response to nitrogen (N) applied in an anhydrous ammonia study being conducted at the ISU research farm between Ames and Boone. Following are some final observations (July 7, 2008).
Wait Until Soil Temps Drop Before Applying Anhydrous Ammonia,
2017
Iowa State University
Wait Until Soil Temps Drop Before Applying Anhydrous Ammonia, John E. Sawyer, Barbara Stewart, William Ehm
John E. Sawyer
With the early harvest, Iowa’s conservation leaders are encouraging farmers to wait until soil temperatures lower before applying anhydrous ammonia (NH3) this fall. Anhydrous ammonia applied before daily soil temperatures remain below 50 degrees Fahrenheit and continue trending lower can result in the nitrogen loss that can impact crop development and have negative environmental impacts, such as enhanced leaching into groundwater and streams once converted to nitrate.
Wet Conditions And Change In Soil Profile Nitrate,
2017
Iowa State University
Wet Conditions And Change In Soil Profile Nitrate, John E. Sawyer
John E. Sawyer
I wrote an ICM News article February 21, 2013, that provided a summary of fall soil profile nitrate sampling results following the 2012 corn harvest. As I cautioned in that and other articles, the amount of nitrate-N that might remain for a 2013 corn crop depends on springtime rainfall. Unfortunately, much of Iowa has received considerable precipitation since soils thawed, especially the eastern two-thirds of Iowa. The two maps of the Midwest region show the total precipitation and deviation from normal since March 7, 2013. Tile lines are flowing again, and nitrate in the profile will move with percolating water. …
Uan And Preemergence Herbicide Applications On Emerged Corn,
2017
Iowa State University
Uan And Preemergence Herbicide Applications On Emerged Corn, Michael D. Owen, John E. Sawyer, Robert G. Hartzler
John E. Sawyer
Planting the Iowa 2007 corn crop is somewhat behind recent years, and in efforts to stay ahead of the game, many fields will be planted before being treated with nitrogen (N) and/or herbicides. Corn in some of these fields will emerge before applications of these materials are made, raising concerns over the safety of postemergence applications of urea-ammonium nitrate (UAN) solution, with or without herbicides.
Soybean Top Dieback Shows Up In Iowa Again,
2017
Iowa State University
Soybean Top Dieback Shows Up In Iowa Again, Xiao-Bing Yang, John E. Sawyer
John E. Sawyer
Extension field agronomists report the occurrence of soybean top dieback in northeastern Iowa soybean fields this week. Soybean top dieback symptoms have shown up occasionally since it was first reported by Jim Fawcett and Jerry Long in Cedar County a few years ago. Last year it was also found in eastern and central Iowa.
Seasonal And Rotational Influences On Corn Nitrogen Requirements,
2017
Iowa State University
Seasonal And Rotational Influences On Corn Nitrogen Requirements, John E. Sawyer, Daniel W. Barker
John E. Sawyer
This project is designed to study the N fertilization needs in continuous corn (C-C) and corn rotated with soybeans (C-S) as influenced by location and climate. Multiple rates of fertilizer N are 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 the determination of N requirements for each rotation practice, differences that exist between the two rotations, and responses to applied N across different soils and climatic conditions. It will also allow for the evaluation of tools used to adjust …
