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Articles 31 - 60 of 396
Full-Text Articles in Entire DC Network
Corn Nitrogen Rate Response And Crop Yield In A Rye Cover Crop System, John E. Sawyer, Jose L. Pantoja, Daniel W. Barker
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
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
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
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
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, Jose L. Pantoja, Krishna P. Woli, John E. Sawyer, Daniel W. Barker
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, 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
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?, John E. Sawyer, Antonio P. Mallarino
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), John E. Sawyer
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, John E. Sawyer, Barbara Stewart, William Ehm
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, John E. Sawyer
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, Michael D. Owen, John E. Sawyer, Robert G. Hartzler
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, Xiao-Bing Yang, John E. Sawyer
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, John E. Sawyer, Daniel W. Barker
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 …
Seasonal And Rotational Influences On Corn Nitrogen Requirements, John E. Sawyer, Daniel W. Barker
Seasonal And Rotational Influences On Corn Nitrogen Requirements, John E. Sawyer, Daniel W. Barker
John E. Sawyer
This project was designed to study the N fertilization needs in continuous corn (CC) and corn rotated with soybean (SC) 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 the determination of N requirements for each rotation practice, 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.
Seasonal And Rotational Influences On Corn Nitrogen Requirements, John E. Sawyer, Daniel W. Barker
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 soybean (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 help determine N requirements for each rotation practice, differences that exist between the two rotations, responses to applied N across different soils and different climatic conditions. It will also allow for the evaluation of tools used to adjust N application.
Seasonal And Rotational Influences On Corn Nitrogen Requirements, John E. Sawyer, Daniel W. Barker, John Lundvall
Seasonal And Rotational Influences On Corn Nitrogen Requirements, John E. Sawyer, Daniel W. Barker, John Lundvall
John E. Sawyer
This project is designed to study the N fertilization needs of 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 help determine N requirements for each rotational practice, differences that exist between the two rotations, and responses to applied N across different soils and different climatic conditions. It will also allow for the evaluation of tools used to adjust N …
Seasonal And Rotational Influences On Corn Nitrogen Requirements, John E. Sawyer, Daniel W. Barker
Seasonal And Rotational Influences On Corn Nitrogen Requirements, John E. Sawyer, Daniel W. Barker
John E. Sawyer
This project was designed to study the N fertilization needs in continuous corn (CC) and corn rotated with soybean (SC) 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 the 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.
Seasonal And Rotational Influences On Corn Nitrogen Requirements, John E. Sawyer, Daniel W. Barker
Seasonal And Rotational Influences On Corn Nitrogen Requirements, John E. Sawyer, Daniel W. Barker
John E. Sawyer
This project was designed to study the N fertilization needs in continuous corn (CC) and corn rotated with soybean (SC) 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 the 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.
Seasonal And Rotational Influences On Corn Nitrogen Requirements, John E. Sawyer, Daniel W. Barker
Seasonal And Rotational Influences On Corn Nitrogen Requirements, John E. Sawyer, Daniel W. Barker
John E. Sawyer
This project was designed to study the N fertilization needs in continuous corn (CC) and corn rotated with soybean (SC) 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, 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.
Seasonal And Rotational Influences On Corn Nitrogen Requirements, John E. Sawyer, Daniel W. Barker
Seasonal And Rotational Influences On Corn Nitrogen Requirements, John E. Sawyer, Daniel W. Barker
John E. Sawyer
This project was designed to study the N fertilization needs in continuous corn (CC) and corn rotated with soybean (SC) 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, responses to applied N across different soils and climatic conditions, and evaluation of tools used to adjust N application.
Phosphorus And Potassium In Silage Harvest Of Drought-Damaged Corn, John E. Sawyer, Antonio P. Mallarino
Phosphorus And Potassium In Silage Harvest Of Drought-Damaged Corn, John E. Sawyer, Antonio P. Mallarino
John E. Sawyer
The dry conditions this summer are resulting in quite variable corn growth and production potential. Some livestock producers are beginning harvest of corn damaged by drought conditions for silage. Corn silage harvest results in more phosphorus (P) and potassium (K) removal than grain alone because almost the entire plant is harvested. The increased amount removed with silage differs for P and K because the relative amount of P and K is different in corn vegetative parts than in grain. For P there can be approximately four times greater amount of P per ton of dry matter in grain than vegetative …
Nitrogen Loss: How Does It Happen?, John E. Sawyer
Nitrogen Loss: How Does It Happen?, John E. Sawyer
John E. Sawyer
For the period April 1 through May 6, 2007, much of Iowa received more than 5 inches of rainfall (May 6, 2007 AWIS Inc. report). The Northwest, North-Central, and East-Central districts averaged slightly less than 5 inches, and the West-Central and Southwest districts more than 9 inches. With the large rainfall and flooding conditions, many producers are wondering about nitrogen (N) losses. While this period certainly has an influence on N in the soil, excessively wet conditions later in the spring are especially important for N losses. Early to mid-June will be a critical period to assess crop growth and …
Developing And Using The Iowa P-Index, John E. Sawyer
Developing And Using The Iowa P-Index, John E. Sawyer
John E. Sawyer
Movement of phosphorus (P) from farm fields to surface waters can elevate P above critical levels for aquatic plant growth and thus enhance nutrient enrichment and seasonal deficient oxygen, a process called eutrophication. Phosphorus commonly controls vegetative production in freshwater bodies, and hence the potential for eutrophication. The sourcing of P from production fields (including P from soil, manure, and fertilizer) is one area identified as being an important contributor of total P entering surface waters, and hence significantly contributing to water quality concerns. In recent years considerable effort has focused on developing methods to assess risk of P loss …
Modeling Long-Term Corn Yield Response To Nitrogen Rate And Crop Rotation, Laila A. Puntel, John E. Sawyer, Daniel Barker, Ranae N. Dietzel, Hanna Poffenbarger, Michael J. Castellano, Kenneth J. Moore, Peter Thorburn, Sotirios Archontoulis
Modeling Long-Term Corn Yield Response To Nitrogen Rate And Crop Rotation, Laila A. Puntel, John E. Sawyer, Daniel Barker, Ranae N. Dietzel, Hanna Poffenbarger, Michael J. Castellano, Kenneth J. Moore, Peter Thorburn, Sotirios Archontoulis
John E. Sawyer
Improved prediction of optimal N fertilizer rates for corn (Zea mays L.) can reduce N losses and increase profits. We tested the ability of the Agricultural Production Systems sIMulator (APSIM) to simulate corn and soybean (Glycine max L.) yields, the economic optimum N rate (EONR) using a 16-year field-experiment dataset from central Iowa, USA that included two crop sequences (continuous corn and soybean-corn) and five N fertilizer rates (0, 67, 134, 201, and 268 kg N ha-1) applied to corn. Our objectives were to: (a) quantify model prediction accuracy before and after calibration, and report calibration steps; (b) compare crop …
The Illinois Soil Nitrogen Test: Should It Be Used In Iowa?, John E. Sawyer, Mohammod Ali Tabatabai
The Illinois Soil Nitrogen Test: Should It Be Used In Iowa?, John E. Sawyer, Mohammod Ali Tabatabai
John E. Sawyer
The test was developed several years ago at the University of Illinois by researchers in the Department of Natural Resources and Environmental Sciences. It is a laboratory procedure designed to measure N liberated from soil heated for 5 hours with dilute alkali solution (sodium hydroxide). The test does not measure nitrate, but does measure exchangeable ammonium and a fraction of soil organic N.
Surface Waters: Ammonium Is Not Ammonia – Part 3, John E. Sawyer, Matthew J. Helmers
Surface Waters: Ammonium Is Not Ammonia – Part 3, John E. Sawyer, Matthew J. Helmers
John E. Sawyer
Two previous ICM News articles outlined the difference between ammonium and ammonia, the relationship between the two nitrogen forms, and the implication of a combined (ammonium-N plus ammonia-N) analysis related to water quality criteria for aquatic life and chlorination treatment for drinking water.This article focuses on the potential sourcing of ammonium and ammonia in surface waters. Ammonium and ammonia in surface water systems can originate from many sources, and are naturally occurring forms of nitrogen. Predominant sources will vary on a watershed or sub-watershed basis. Also, sources and concentrations are greatly influenced by hydrology, including timing and volume of water …
Sulfur Fertilizer Application To Corn And Soybean, John E. Sawyer, Daniel W. Barker
Sulfur Fertilizer Application To Corn And Soybean, John E. Sawyer, Daniel W. Barker
John E. Sawyer
Historically sulfur (S) application has not been recommended on Iowa soils for corn and soybean production. The soil supply or combination from sources such as manure or precipitation has met crop S needs. However, soil S levels or supply will become depleted with prolonged crop removal, sulfate leaching, low precipitation deposition, and declining soil organic matter. The objective of this study was to determine the responsiveness of corn and soybean to S application (first year and residual second year) and S fertilizer material at multiple sites across Iowa soils and climatic conditions.
Sulfur Fertilizer Application To Corn And Soybean, John E. Sawyer, Daniel W. Barker
Sulfur Fertilizer Application To Corn And Soybean, John E. Sawyer, Daniel W. Barker
John E. Sawyer
Historically, sulfur (S) application has not been recommended on Iowa soils for corn and soybean production. Soil supply or combination from sources such as manure or precipitation has met crop S needs. However, soil S levels or supply may become depleted with prolonged crop removal, sulfate leaching, low precipitation deposition, and declining soil organic matter. The objective of this study was to determine if corn and soybean yields would respond to S fertilizer rate and material at multiple sites across Iowa soils and climatic conditions.
Sulfur Fertilizer Application To Corn And Soybean, John E. Sawyer, Daniel W. Barker
Sulfur Fertilizer Application To Corn And Soybean, John E. Sawyer, Daniel W. Barker
John E. Sawyer
Historically sulfur (S) application has not been recommended on Iowa soils for corn and soybean production. The soil supply or combination from sources such as manure or precipitation has met crop S needs. However, soil S levels or supply will become depleted with prolonged crop removal, sulfate leaching, low precipitation deposition, and declining soil organic matter. The objective of this study was to determine the responsiveness of corn and soybean to S application (first year and residual second year) and S fertilizer material at multiple sites across Iowa soils and climatic conditions.