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Cover Crop Effect On Subsequent Wheat Yield In The Central Great Plains, David Nielsen, Drew Lyon, Robert Higgins, Gary Hergert, Johnathon Holman, Merle Vigil 2016 Washington State University

Cover Crop Effect On Subsequent Wheat Yield In The Central Great Plains, David Nielsen, Drew Lyon, Robert Higgins, Gary Hergert, Johnathon Holman, Merle Vigil

David C. Nielsen

Crop production systems in the water-limited environment of the semiarid central Great Plains may not have potential to profitably use cover crops because of lowered subsequent wheat (Triticum asestivum L.) yields following the cover crop. Mixtures have reportedly shown less yield-reducing effects on subsequent crops than single-species plantings. This study was conducted to determine winter wheat yields following both mixtures and single-species plantings of spring-planted cover crops. The study was conducted at Akron, CO, and Sidney, NE, during the 2012–2013 and 2013–2014 wheat growing seasons under both rainfed and irrigated conditions. Precipitation storage efficiency before wheat planting, wheat ...


Emerged Corn, Herbicides And Nitrogen, Robert G. Hartzler, John E. Sawyer 2016 Iowa State University

Emerged Corn, Herbicides And Nitrogen, Robert G. Hartzler, John E. Sawyer

John E. Sawyer

The rapid pace of planting in late April followed by rain has resulted in many fields having emerged corn before preemergence herbicides and nitrogen applications have been completed. Of particular concern are no-till fields where planting was completed prior to killing emerged weeds.


Enhancing Corn Yield In A Winter Cereal Rye Cover Cropping System, Swetabh Patel, John Lundvall, John Sawyer 2016 Iowa State University

Enhancing Corn Yield In A Winter Cereal Rye Cover Cropping System, Swetabh Patel, John Lundvall, 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 ...


Enhancing Corn Yield In A Winter Cereal Ryecover Cropping System, Swetabh Patel, John Lundvall, John Sawyer 2016 Iowa State University

Enhancing Corn Yield In A Winter Cereal Ryecover Cropping System, Swetabh Patel, John Lundvall, 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 ...


Enhancing Corn Yield In A Winter Cereal Rye Cover Cropping System, Swetabh Patel, John Lundvall, John Sawyer 2016 Iowa State University

Enhancing Corn Yield In A Winter Cereal Rye Cover Cropping System, Swetabh Patel, John Lundvall, 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 ...


Do Active Canopy Sensors Measure Biomass Or Chlorophyll In Corn?, Matthew Meade, Daniel W. Barker, John E. Sawyer 2016 Iowa State University

Do Active Canopy Sensors Measure Biomass Or Chlorophyll In Corn?, Matthew Meade, Daniel W. Barker, John E. Sawyer

John E. Sawyer

Vegetative indices from canopy sensors are currently being used as a tool to measure N deficiency in corn (Zea Mays L.). Symptoms of N deficiency include stunted growth (reduced biomass) and yellowing (reduced chlorophyll). It is unclear which sensor index is most useful. The objective was to determine if canopy sensor indices (NDVI and CHL) measure plant biomass or plant chlorophyll.


Cornstalk Nitrate Interpretation, John E. Sawyer 2016 Iowa State University

Cornstalk Nitrate Interpretation, John E. Sawyer

John E. Sawyer

So you've gotten back the results of the cornstalk nitrate samples collected this fall. Now, what do the results mean? The stalk nitrate test is based on the concentration of nitrate-N in the lower cornstalk (8-inch segment from 6 to 14 inches above the ground) when the plant reaches maturity (ISU Extension publication PM 1584, Cornstalk testing to evaluate nitrogen management). In general, as the amount of plant-available N in the soil during the time period before plant maturity increases, nitrate in the lower stalk increases. However, the stalk nitrate-N concentration can be greatly influenced by other external and ...


Don't Double Dip Soybean, John E. Sawyer 2016 Iowa State University

Don't Double Dip Soybean, John E. Sawyer

John E. Sawyer

The approach for determining nitrogen (N) application rates for producing corn has changed, so don't be tempted to subtract a "soybean credit." Current N rate guidelines for corn in Iowa and many nearby states now give suggestions based on specific rotations instead of "crediting" from rates for continuous corn. This means that suggested N rates are those that should be applied for the specific rotation and should not be further modified to account for having a legume in the rotation. In Iowa State University Extension publication Nitrogen Fertilizer Recommendations for Corn in Iowa, PM 1714, for example, a range ...


Corn Response To Supplemental Nitrogen, John E. Sawyer 2016 Iowa State University

Corn Response To Supplemental Nitrogen, John E. Sawyer

John E. Sawyer

Once you have determined that enough nitrogen (N) loss has occurred and that supplemental N application is needed, what's next? Rainfall after supplemental N applications will be important for plant uptake. If the applied N is within the active root system, and if there is a need for the N, corn yield can be increased with N applied until shortly after silking. If the supplemental N stays near the soil surface, and is not available to the plant, then the application will be wasted.


Corn: Uneven Early-Season Growth Can Mean Uneven Tasseling, Roger W. Elmore, John E. Sawyer 2016 Iowa State University

Corn: Uneven Early-Season Growth Can Mean Uneven Tasseling, Roger W. Elmore, John E. Sawyer

John E. Sawyer

Uneven growth reports on Iowa corn proliferated during the early part of the 2009 growing season. As we transition into reproductive growth stages, expect to see variation within fields and hybrids as a result of various early-season stresses.


Drought Impacts On Soil Fertility Management, John E. Sawyer 2016 Iowa State University

Drought Impacts On Soil Fertility Management, John E. Sawyer

John E. Sawyer

If crop production was severely reduced because of dry conditions this year, there are a few items you can consider when planning for next year's crop. One, with severely damaged crops and low yields you might credit some of the phosphorus (P) and potassium (K) applied for this year's crop to next year, as much less removal will occur in grain harvest of the lower than expected yield.


Corn Seedling Damage From Ammonia, John E. Sawyer 2016 Iowa State University

Corn Seedling Damage From Ammonia, John E. Sawyer

John E. Sawyer

There have been several reports of corn seedlings being damaged from ammonia, even fall applied anhydrous ammonia. Ammonia injury has been noted in past springs and more frequently occurs with shallow placed ammonia, ammonia applied near the time of planting, urea placed near the seed, and with dry soil conditions.


Corn And Soybean Production With A Winter Rye Cover Crop, John E. Sawyer, Jose L. Pantoja, Daniel W. Barker 2016 Iowa State University

Corn And Soybean Production With A Winter Rye Cover Crop, John E. Sawyer, Jose L. Pantoja, Daniel W. Barker

John E. Sawyer

The objective of this project was 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 were 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 was 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.


Corn Residue Harvesting Effects On Yield Response To N Fertilization, Jose L. Pantoja, John E. Sawyer, Daniel W. Barker, Mahdi Al-Kaisi 2016 Iowa State University

Corn Residue Harvesting Effects On Yield Response To N Fertilization, Jose L. Pantoja, John E. Sawyer, Daniel W. Barker, Mahdi Al-Kaisi

John E. Sawyer

Producers have many choices of diverse tillage practices for their corn (Zea mays L.) production systems. However, no-till has become an important soil management practice to help reduce water and wind erosion, as well as nutrient runoff, while conserving soil moisture for crop use. No-till systems also help farmers by saving labor and time, as well as reducing farm costs due to less equipment and fuel consumption. Nevertheless, no-till production is typically more successful and has higher crop yield on moderately to well drained medium-textured soils (Bitzer, 1998), compared to soils with poor internal drainage and high clay.


Corn Leaf Potassium Deficiency Symptoms, John E. Sawyer, Antonio P. Mallarino 2016 Iowa State University

Corn Leaf Potassium Deficiency Symptoms, John E. Sawyer, Antonio P. Mallarino

John E. Sawyer

Potassium (K) leaf deficiency symptoms have recently appeared in some cornfields. Early-season symptoms typically show when corn begins rapid growth, calf to knee-high (V6-V8 growth stages), and the K uptake rate accelerates as plant demand responds to this rapid growth. Because K is maintained in the plant in the K+ ion form, it is readily moved from older tissue to the growth regions, hence deficiency symptoms appear on the older leaves. On corn, symptoms show as yellowing to necrosis of the leaf margins on older leaves.


Corn And Soybean Response To Sulfur Application Rate, David Rueber, John E. Sawyer 2016 Iowa State University

Corn And Soybean Response To Sulfur Application Rate, David Rueber, John E. Sawyer

John E. Sawyer

Historically, sulfur (S) application has not been recommended on Iowa soils for corn and soybean production. Soil supply, or a combination from sources such as soil organic matter, profile sulfate, manure, and precipitation have met crop S needs. However, over the past several years, S deficiencies in alfalfa and corn have been documented. Large crop yield responses have been measured in some fields containing soils with low organic matter, side-slope landscape position, or coarse soil texture, especially in northeastern Iowa. The objective of this study was to determine S response of corn and soybean in north-central Iowa.


Corn Residue Harvesting Effects On Yield Response To N Fertilization, Jose L. Pantoja, John E. Sawyer, Daniel W. Barker, Mahdi Al-Kaisi 2016 Iowa State University

Corn Residue Harvesting Effects On Yield Response To N Fertilization, Jose L. Pantoja, John E. Sawyer, Daniel W. Barker, Mahdi Al-Kaisi

John E. Sawyer

Producers have many choices of diverse tillage practices for their corn (Zea mays L.) production systems. However, no-till has become an important soil management practice to help reduce water and wind erosion, as well as nutrient runoff, while conserving soil moisture for crop use. No-till systems also help farmers by saving labor and time, as well as reducing farm costs due to less equipment and fuel consumption. Nevertheless, no-till production is typically more successful and has higher crop yield on moderately to well drained medium-textured soils (Bitzer, 1998), compared to soils with poor internal drainage and high clay.


Corn And Soybean Production With A Winter Rye Cover Crop, John E. Sawyer, Jose L. Pantoja, Daniel W. Barker 2016 Iowa State University

Corn And Soybean Production With A Winter Rye 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 were 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 was 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.


Corn And Soybean Production With A Winter Rye Cover Crop, John E. Sawyer, Jose L. Pantoja, Daniel W. Barker 2016 Iowa State University

Corn And Soybean Production With A Winter Rye 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 were 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 was 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.


Corn And Soybean Production With A Winter Rye Cover Crop, John E. Sawyer, Jose L. Pantoja, Daniel W. Barker 2016 Iowa State University

Corn And Soybean Production With A Winter Rye Cover Crop, John E. Sawyer, Jose L. Pantoja, Daniel W. Barker

John E. Sawyer

The objective of this project was 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 were 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 was 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.


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