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Full-Text Articles in Agriculture
Impact Of Nitrogen Application Timing On Corn Production, John E. Sawyer, Daniel W. Barker, John P. Lundvall
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
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
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 …
In-Season Nitrogen Fertilization Of Soybean, J. E. Sawyer, D. W. Barker
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
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
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.
Seasonal And Rotational Influences On Corn Nitrogen Fertilization In Southwest Iowa, John Sawyer, Daniel Barker
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.
Enhancing Corn Yield In A Winter Cereal Rye Cover Crop System In Southwest Iowa, John Lundvall, Swetabh Patel, John Sawyer
Enhancing Corn Yield In A Winter Cereal Rye Cover Crop System In Southwest Iowa, John Lundvall, Swetabh Patel, John Sawyer
John E. Sawyer
Water quality impairment related to nitrogen (N) is a concern in Iowa, including meeting nitrate (NO3) drinking water standards and reducing the amount of N lost to the Gulf of Mexico. The Iowa Nutrient Reduction Strategy science assessment identified a rye cover crop as an important in-field management practice for reducing N and phosphorus (P) loss from fields (31% NO3-N and 29% P), and for reducing soil erosion. However, the science assessment identified a corn yield reduction of 6 percent when grown following a rye cover crop. Lower corn yield with use of a cover crop is unacceptable to farmers, …
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.
Revised Alfalfa Fertilizer Recommendations For A Changing Environment Greatly Improves Profitability, Brian Lang, John E. Sawyer, Daniel Barker, Ken Pecinovsky
Revised Alfalfa Fertilizer Recommendations For A Changing Environment Greatly Improves Profitability, Brian Lang, John E. Sawyer, Daniel Barker, Ken Pecinovsky
John E. Sawyer
During the last decade, an ever-increasing percentage of alfalfa fields in northeast Iowa have been exhibiting signs of reduced growth and vigor, resulting in declining profitability. Iowa State University Extension in northeast Iowa initiated an investigation into this problem. Sixteen research trials conducted in northeast Iowa over the next 6 years as both on-farm trials and at the northeast ISU research farm uncovered widespread sulfur deficiency problems in alfalfa production. Over 90 ISU Extension educational meetings in northeast Iowa, and extensive use of the media, communicated this issue and tools to address it to farmers and agricultural providers. Survey results …
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 …