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Articles 31 - 60 of 223
Full-Text Articles in Life Sciences
Making Every Fertilizer Nitrogen Dollar Pay, John E. Sawyer
Making Every Fertilizer Nitrogen Dollar Pay, John E. Sawyer
John E. Sawyer
High fertilizer nitrogen (N) prices will add significant costs to corn production this year. Concurrently, spot shortages of some N products may occur. What steps can producers take to get the most return from added N? What are some options for managing fertilizer applications?
Is It Iron Or Potassium Deficiency?, John E. Sawyer
Is It Iron Or Potassium Deficiency?, John E. Sawyer
John E. Sawyer
Cool early summer temperatures have promoted symptom development of soybean iron chlorosis in some parts of Iowa, according to reports from Iowa State University field crop specialists and samples submitted to the Iowa State University Plant Disease Clinic. Yellowing soybean caused by iron chlorosis was a problem last growing season, and it may be a problem again for some growers this season.
Measuring The Nitrogen Status, John E. Sawyer
Measuring The Nitrogen Status, John E. Sawyer
John E. Sawyer
Tools are available that can aid decisions about applying supplemental nitrogen (N) when there have been losses of applied fertilizer or manure N. These can provide more site-specific information than estimating losses and can also provide N rate application guidance.
Nitrogen Fertilization Rates For Corn Production, John E. Sawyer
Nitrogen Fertilization Rates For Corn Production, John E. Sawyer
John E. Sawyer
October 13, 2014 – There has been a large change in corn grain prices this fall. How might that affect recommended nitrogen (N) fertilizer or manure-N application rates, and planning for the 2015 crop? The answer depends on more than just the price of corn, but also the price of nitrogen. It is the ratio of these prices (price ratio, where the $/lb actual N is divided by the $/bu corn; example, $0.50/lb N and $3.50/bu corn is a 0.14 price ratio). Both prices are important and influence recommended N rates as the ratio reflects the last unit of N …
N Management Influences On N Losses Through Tile Lines, Gyles W. Randall, John E. Sawyer
N Management Influences On N Losses Through Tile Lines, Gyles W. Randall, John E. Sawyer
John E. Sawyer
Subsurface tile drainage from row-crop agricultural production systems has been identified as a major source of nitrate entering surface waters in the Mississippi River Basin. Tile drainage studies have been conducted on three drainage research facilities at two locations in Minnesota since 1973. Nutrient and crop management systems, including rate and time of nitrogen (N) application, N sources (fertilizer, dairy manure, and hog manure), nitrification inhibitors, cropping systems, and tillage systems have been evaluated to determine their agronomic and environmental characteristics. Results from these studies have been instrumental in the development of best management practices for nutrient management in Minnesota.
Making Fertilization Decisions As Fertilizer Prices Escalate And Production Costs Are High - Part 2, John E. Sawyer, Antonio P. Mallarino
Making Fertilization Decisions As Fertilizer Prices Escalate And Production Costs Are High - Part 2, John E. Sawyer, Antonio P. Mallarino
John E. Sawyer
This article continues the discussion begun in Making Fertilization Decisions As Fertilizer Prices Escalate and Production Costs Are High - Part 1 where soil testing and phosphorus and potassium applications were discussed.
Liquid Swine Manure Impact On First-Year Soybeans And Subsequent-Year Corn, John Lundvall, John E. Sawyer, Antonio P. Mallarino, Monica Barbazan, Kenneth T. Pecinovsky
Liquid Swine Manure Impact On First-Year Soybeans And Subsequent-Year Corn, John Lundvall, John E. Sawyer, Antonio P. Mallarino, Monica Barbazan, Kenneth T. Pecinovsky
John E. Sawyer
Liquid swine manure is a valuable crop nutrient source in Iowa. Producers may lack confidence in manure nutrient availability and ability to maintain high crop yields, and therefore may apply additional fertilizer or high manure rates to ensure adequate soil fertility levels. This results in over-application, reduced profits, and potential environmental impacts. Objectives of this project include learning more about liquid swine manure nitrogen (N) and phosphorus (P) as nutrient sources for first-year soybean and subsequent (second)-year corn production, evaluating crop yield with manure compared with commercial fertilizer, monitoring soil P test change with manure application, and helping crop and …
Nitrogen Fertilization Of Corn Grown With A Cover Crop, John E. Sawyer, Jose L. Pantoja, Daniel W. Barker
Nitrogen Fertilization Of Corn Grown With A Cover Crop, John E. Sawyer, Jose L. Pantoja, Daniel W. Barker
John E. Sawyer
Objectives of this project were to study corn nitrogen (N) fertilization requirement and corn-soybean yield response when grown in a cover crop system. Multiple rates of N fertilizer are applied, with measurement of corn yield response to applied N and soybean yield with and without a fall planted winter rye cover crop. The study is being conducted at several research farms, with the intent for study across multiple years to allow comparison of with and without a cover crop system across varying soil and climatic conditions.
New Manure Nutrient Management Research Available, John E. Sawyer
New Manure Nutrient Management Research Available, John E. Sawyer
John E. Sawyer
Iowa crop and livestock farmers, as top producers of corn, soybeans, pork, eggs, and other agricultural products – are in an advantageous position economically and environmentally. Not only do livestock producers enjoy the benefits of locally grown crops for the feed that they need, but crop producers also enjoy the benefits of using manure as a nutrient source. To help producers make the most of Iowa’s available manure nutrient resources, Iowa State University Extension recently developed an updated publication, Using Manure Nutrients for Crop Production - PMR 1003.
Management Of Phosphorus For Crop Production, Antonio P. Mallarino, John E. Sawyer, John Creswell, Michael J. Tidman
Management Of Phosphorus For Crop Production, Antonio P. Mallarino, John E. Sawyer, John Creswell, Michael J. Tidman
John E. Sawyer
This article continues a series that provides producers with information that will aid in phosphorus (P) management and in understanding environmental issues related to P management. It focuses on P management for crop production with attention to fertilization strategies, application methods, related soil management aspects, and environmental issues.
Nitrogen Fertilization Of Corn Grown With A Cover Crop, John E. Sawyer, Jose L. Pantoja, Daniel W. Barker
Nitrogen Fertilization Of Corn Grown With A Cover Crop, John E. Sawyer, Jose L. Pantoja, Daniel W. Barker
John E. Sawyer
Objectives of this project were to study corn nitrogen (N) fertilization requirement and corn-soybean yield response when grown in a cover crop system. Multiple rates of N fertilizer are applied, with measurement of corn yield response to applied N and soybean yield with and without a fall planted winter rye cover crop. The study is being conducted at several research farms, with the intent for study across multiple years to allow comparison of with and without a cover crop system across varying soil and climatic conditions.
Nitrogen Fertilization Of Corn Grown With A Cover Crop, John E. Sawyer, Jose L. Pantoja, Daniel W. Barker
Nitrogen Fertilization Of Corn Grown With A Cover Crop, John E. Sawyer, Jose L. Pantoja, Daniel W. Barker
John E. Sawyer
Objectives of this project were to study corn nitrogen (N) fertilization requirement and corn-soybean yield response when grown in a rye cover cropping system. Multiple rates of N fertilizer are applied, with measurement of corn yield response to applied N and soybean yield with and without a fall planted winter rye cover crop. The study is being conducted at multiple research farms, with the intent for comparison of with and without a cover crop system across varying soil and climatic conditions in Iowa.
Measuring The Nitrogen Status -- 2007, John E. Sawyer
Measuring The Nitrogen Status -- 2007, John E. Sawyer
John E. Sawyer
Tools are available that can aid decisions about applying supplemental nitrogen (N) if losses from applied fertilizer or manure are suspected. These can provide more site-specific information than estimating losses and can also provide N rate application guidance.
In-Season N Fertilization Strategies Using Active Sensors, Daniel Barker, John Sawyer
In-Season N Fertilization Strategies Using Active Sensors, Daniel Barker, John Sawyer
John E. Sawyer
The objectives of this project were to measure corn yield response to applied nitrogen (N) fertilizer based on active canopy sensing during the mid-vegetative corn growth stage (V10) and compare yield and N use efficiency between pre-plant N (PP-N), pre-plant + sensor N (PP+S-N), split N strategy (SNS), and rescue N strategy (RNS).
Integrating Plant Litter Quality, Soil Organic Matter Stabilization, And The Carbon Saturation Concept, Michael J. Castellano, Kevin E. Mueller, Daniel C. Olk, John E. Sawyer, Johan Six
Integrating Plant Litter Quality, Soil Organic Matter Stabilization, And The Carbon Saturation Concept, Michael J. Castellano, Kevin E. Mueller, Daniel C. Olk, John E. Sawyer, Johan Six
John E. Sawyer
No abstract provided.
In-Season N Fertilization Strategies Using Active Sensors, Daniel Barker, John Sawyer
In-Season N Fertilization Strategies Using Active Sensors, Daniel Barker, John Sawyer
John E. Sawyer
The objectives of this project were to measure corn yield response to applied nitrogen (N) fertilizer based on active canopy sensing during the mid-vegetative corn growth stage (V10) and compare yield and N use efficiency between pre-plant N (PP-N), pre-plant + sensor N (PP+S-N), split N strategy (SNS), and rescue N strategy (RNS).
Estimating Nitrogen Losses, John E. Sawyer
Estimating Nitrogen Losses, John E. Sawyer
John E. Sawyer
Many areas of central to southern Iowa have experienced well above normal rainfall this spring, with several large rainfall events (see map). In the early spring, cold soils help reduce potential for nitrate-N loss due to slow accumulation of nitrate and slow denitrification. However, continued wet soil conditions into June with warm soils, prolonged saturation and tile drainage enhance nitrate loss.
In-Season N Fertilization Strategies Using Active Sensors, Daniel W. Barker, John E. Sawyer
In-Season N Fertilization Strategies Using Active Sensors, Daniel W. Barker, John E. Sawyer
John E. Sawyer
The objectives of this project were to measure corn yield response to nitrogen (N) fertilizer when applied during the V10 corn growth stage, and compare yield and N use efficiency between pre-plant N (PP-N), pre-plant + sensor N (PP+S-N), split N strategy (SNS), and rescue N strategy (RNS). The study was conducted using two crop rotations (corn-soybean and continuous corn) at multiple research farms. In-season applied N was urea treated with Agrotain® .
Estimating Nitrogen Losses In Wet Corn Fields, John E. Sawyer
Estimating Nitrogen Losses In Wet Corn Fields, John E. Sawyer
John E. Sawyer
Some areas of Iowa have recently received heavy rainfall, resulting in soils saturated or with standing water. Following are excerpts from an article published in 2011 when similar conditions occurred. The early spring 2014 season was on the cold side, so conversion of ammonium fertilizers to nitrate should have been slower than normal. This could be helpful for avoidance of nitrate losses, as would recent sidedress application of ammonium-containing fertilizers. However, wet soils in June are much more conducive to nitrate loss (compared to early spring) as soils are warm and, with prolonged saturation and tile flow, losses mount. Remember, …
In-Season N Fertilization Strategies Using Active Sensors, Daniel Barker, John Sawyer
In-Season N Fertilization Strategies Using Active Sensors, Daniel Barker, John Sawyer
John E. Sawyer
The objectives of this project were to measure corn yield response to applied nitrogen (N) fertilizer based on active canopy sensing during the mid-vegetative corn growth stage (V10) and compare yield and N use efficiency between pre-plant N (PP-N), pre-plant + sensor N (PP+S-N), split N strategy (SNS), and rescue N strategy (RNS).
In-Season N Fertilization Strategies Using Active Sensors, Daniel Barker, John Sawyer
In-Season N Fertilization Strategies Using Active Sensors, Daniel Barker, John Sawyer
John E. Sawyer
The objectives of this project were to measure corn yield response to applied nitrogen (N) fertilizer based on active canopy sensing during the mid-vegetative corn growth stage (V10) and compare yield and N use efficiency between pre-plant N (PP-N), pre-plant + sensor N (PP+S-N), split N strategy (SNS), and rescue N strategy (RNS).
In-Season N Fertilization Strategies Using Active Sensors, Daniel Barker, John Sawyer
In-Season N Fertilization Strategies Using Active Sensors, Daniel Barker, John Sawyer
John E. Sawyer
The objectives of this project were to measure corn yield response to applied nitrogen (N) fertilizer based on active canopy sensing during the mid-vegetative corn growth stage (V10) and compare yield and N use efficiency between pre-plant N (PP-N), pre-plant + sensor N (PP+S-N), split N strategy (SNS), and rescue N strategy (RNS).
Equipment Considerations: Liquid Fertilizer, H. Mark Hanna, John E. Sawyer
Equipment Considerations: Liquid Fertilizer, H. Mark Hanna, John E. Sawyer
John E. Sawyer
A review of application equipment considerations can help ensure that your nitrogen fertilizer is properly applied. This article focuses on liquid fertilizers and is the last in a series of three articles (other two in April 9, 2001, Integrated Crop Management issue) about nitrogen fertilizer application and equipment. A primary consideration for equipment is the relatively high application volumes required. For example, a 150-lb N/acre application of 28 percent UAN solution requires an application of 50 gal/acre.
Equipment Considerations: Anhydrous Ammonia, H. Mark Hanna, John E. Sawyer
Equipment Considerations: Anhydrous Ammonia, H. Mark Hanna, John E. Sawyer
John E. Sawyer
Because of abnormal nitrogen fertilizer production, import, and supply this year and with perhaps a short spring application season, some crop producers may use a form of nitrogen fertilizer with which they are unaccustomed. A review of application equipment considerations can help ensure that your nitrogen fertilizer is properly applied. This article focuses on anhydrous ammonia and is the second in a series of three articles about nitrogen fertilizer application and equipment.
Estimating Nitrogen Losses -- Early Spring 2007, John E. Sawyer
Estimating Nitrogen Losses -- Early Spring 2007, John E. Sawyer
John E. Sawyer
One method to judge nitrogen (N) loss is to calculate an estimate. Predicting the exact amount is quite difficult as many factors affect losses. However, estimates can provide guidance for supplemental N applications. While the rainfall this spring has been substantial, it arrived early. This should help moderate loss compared to the same situation occurring in late spring or early summer. In the early spring, soils are colder, so conversion to nitrate and denitrification is slowed. However, having two large rainfall events means that some soils were saturated over a prolonged period. This increases the chance for loss.
Estimating Nitrogen Losses, John E. Sawyer
Estimating Nitrogen Losses, John E. Sawyer
John E. Sawyer
Another wet spring hit Iowa this year. From mid-April to mid-May northwestern Iowa had about 90 percent of normal precipitation, whereas areas of northeastern Iowa received more than 200 percent of normal. Heavy spring rains, recharged subsoils, a high percentage of fall-applied nitrogen (N), and a warm fall have many producers wondering if this is a scenario for repeating last year's N losses. The ponded areas have mostly dried up, but the question is, "Will the effects of that water appear as N deficiency later in the corn growing season?"One difference so far this year is that the excess rain …
Equipment Considerations: Dry Granual Fertilizer, H. Mark Hanna, John E. Sawyer
Equipment Considerations: Dry Granual Fertilizer, H. Mark Hanna, John E. Sawyer
John E. Sawyer
A review of application equipment considerations can help ensure that your nitrogen fertilizer is properly applied. This article focuses on dry granular fertilizers and is the first in a series of three articles about nitrogen fertilizer application and equipment. Because of varying physical properties of dry fertilizer materials, it is important to consider material distribution across the swath as well as application rate.
In-Season N Fertilization Strategies Using Active Sensors, Daniel Barker, John Sawyer
In-Season N Fertilization Strategies Using Active Sensors, Daniel Barker, John Sawyer
John E. Sawyer
The objectives of this project were to measure corn yield response to applied nitrogen (N) fertilizer based on active canopy sensing during the mid-vegetative corn growth stage (V10) and compare yield and N use efficiency between pre-plant N (PP-N), pre-plant + sensor N (PP+S-N), split N strategy (SNS), and rescue N strategy (RNS).
In-Season N Fertilization Strategies Using Active Sensors, Daniel W. Barker, John E. Sawyer
In-Season N Fertilization Strategies Using Active Sensors, Daniel W. Barker, John E. Sawyer
John E. Sawyer
The objectives of this project were to measure corn yield response to nitrogen (N) fertilizer when applied during the V10 corn growth stage, and compare yield and N use efficiency between pre-plant N (PP-N), pre-plant + sensor N (PP+S-N), split N strategy (SNS), and rescue N strategy (RNS). The study was conducted using two crop rotations (corn-soybean and continuous corn) at multiple research farms. In-season applied N was urea treated with Agrotain® .
Equipment Maintenance: Fertilizer Applicators, H. Mark Hanna, John E. Sawyer, Michael J. Tidman
Equipment Maintenance: Fertilizer Applicators, H. Mark Hanna, John E. Sawyer, Michael J. Tidman
John E. Sawyer
Winter is a good time for crop producers and fertilizer dealers to work out the kinks in fertilizer application equipment for economic, environmental, efficiency, and safety reasons. Properly working application equipment translates into getting the most out of every fertilizer dollar. Overapplying to compensate for poorly calibrated equipment wastes money and could mean nutrient-rich runoff and consequently, a potential water quality problem. This article provides some tips for maintaining your fertilizer application equipment.