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2006

Plant Sciences

Proceedings of the Integrated Crop Management Conference

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Can Ground Eggshells Be Used As A Liming Source?, John Holmes, Paul Kassel Nov 2006

Can Ground Eggshells Be Used As A Liming Source?, John Holmes, Paul Kassel

Proceedings of the Integrated Crop Management Conference

Iowa has become the leading egg producing state in the U.S. It's common to see large-scale egg-laying units in many parts of Iowa. Although most plants ship the eggs intact, some facilities have begun to ship liquid eggs. One egg-breaking operation in northern Iowa produces approximately 15 tons of ground eggshells daily. Several other egg-breaking facilities are also operating in Iowa. The eggshells at most locations are ground, stockpiled, and applied to farm fields. Farmers want to know if the eggshells have any value as a liming source, and if so, at what rate they should be applied.


Row Spacing Is Critical For High Yielding Soybeans, Palle Pedersen Nov 2006

Row Spacing Is Critical For High Yielding Soybeans, Palle Pedersen

Proceedings of the Integrated Crop Management Conference

There are fundamental management decisions that give the best opportunity to maintain high yield. Understanding how a soybean plant develops through the season will provide insight into selection of management decisions that should lead to maintaining the soybean genetic yield potential. Row spacing is the third most important variable for maximizing soybean yield after variety selection and planting date. Most research from the Midwest documents that narrows (less than 30 inch) yield greater than wide rows (30 inch or greater). Despite this, the majority of the acres in Iowa are still planted in wide rows. Why7 There are many reasons ...


Production And Use Of Flax And Field Peas In Iowa, Margaret Smith, Mary Wiedenhoeft, Sarah Carlson, Jim Fawcett Nov 2006

Production And Use Of Flax And Field Peas In Iowa, Margaret Smith, Mary Wiedenhoeft, Sarah Carlson, Jim Fawcett

Proceedings of the Integrated Crop Management Conference

Most Iowa crop producers now rely on only two crops, corn and soybeans, for their livelihood. This has led to many challenges, including increased pest problems, such as bean leaf beetles and soybean aphids, a skewed distribution of labor throughout the year, and vulnerability to adverse weather and poor prices. It has also become increasingly difficult to compete in the world market when these commodities can be produced at a lower cost in other countries, such as Brazil. Crop producers are continually looking for a third crop to include in their rotation, but either the economics are not favorable or ...


Brown Stem Rot And Its Interaction With The Soybean Cyst Nematode, G. M. Tabor, G. L. Tylka, C. R. Bronson Nov 2006

Brown Stem Rot And Its Interaction With The Soybean Cyst Nematode, G. M. Tabor, G. L. Tylka, C. R. Bronson

Proceedings of the Integrated Crop Management Conference

Brown stem rot (BSR) of soybeans is caused by the fungal vascular pathogen Cadophora gregata (previously named Phialophora gregata). BSR is an economically important disease of soybeans in the north central United States, being prevalent in 68 to 73% of the soybean fields of Illinois, Iowa, and Minnesota (Workneh et al. 1999). There are two genetic types (called genotypes) of C. gregata that differ in their ability to cause foliar symptoms on susceptible soybeans (Chen et al. 2000). Infection by genotype A of the fungus can result in mild to severe brown discoloration of the pith and severe foliar symptoms ...


Cost-Effective, Performance-Based Environmental Management, John Rodecap, Chad Ingels Nov 2006

Cost-Effective, Performance-Based Environmental Management, John Rodecap, Chad Ingels

Proceedings of the Integrated Crop Management Conference

Iowa has over 19,000 miles of interior rivers and streams, numerous lakes and other natural resources and considerable agricultural production capacity. With such an extensive network of water bodies running through the state it is no surprise that experts have estimated that 90% of Iowa water quality issues are attributed to agricultural land and related activities. This nonpoint source contamination often results from long term actions and will take a long time for measurable outcomes.


Crop Management Practices In Indiana Soybean Production Systems?, Shawn P. Conley, Judith B. Santini Nov 2006

Crop Management Practices In Indiana Soybean Production Systems?, Shawn P. Conley, Judith B. Santini

Proceedings of the Integrated Crop Management Conference

To meet the current and future needs of today's soybean producer it is vital that agricultural researchers and Extension specialists clearly understand the production concerns of our clientele. The objective of this research was to characterize the current management practices of Indiana soybean (Glycine max (L.) Merr.) growers, to identify specific educational needs, and to provide a framework for directing applied soybean research efforts. This assessment was conducted through a direct-mail survey. The results of this survey define distinct similarities and differences among growers of different farm operation size. Large acreage growers (>1000 acres) were more likely to plant ...


Can We Sustain Corn Yield Trends?, Roger Elmore Nov 2006

Can We Sustain Corn Yield Trends?, Roger Elmore

Proceedings of the Integrated Crop Management Conference

Corn yields in Iowa continue at a rate of 2 bushels per acre per year. This is a trend that started back in the 1940's. Driven by hybrid genetic improvement and management the question we need to address is: Are these yield trends sustainable into the future? Will these yield trends continue to increase? If so, for how long7 We can think of yield in four different ways. Yield trends for two of these four are increasing while two are not:


The "Root" Of Drought Problems, Elwynn Taylor Nov 2006

The "Root" Of Drought Problems, Elwynn Taylor

Proceedings of the Integrated Crop Management Conference

Agricultural plants require moisture, but there is more to it than a simple need for rain or irrigation. Under conditions that depend on precipitation to replenish crop available soil moisture it is easy to conclude that the success of the crop depends upon the rain. This is in large measure true , yet considerable variations in yields are found in areas with like precipitation. The "law of limiting factors" holds that at any given moment there is only one factor limiting the growth of a plant. It may be some aspect of soil fertility, or temperature, or light, or carbon dioxide ...


Wisconsin Farmers Take The 2-Pass Challenge Against Weeds, Richard T. Proost, Daniel J. Heider, Chris M. Boerboom Nov 2006

Wisconsin Farmers Take The 2-Pass Challenge Against Weeds, Richard T. Proost, Daniel J. Heider, Chris M. Boerboom

Proceedings of the Integrated Crop Management Conference

Single pass herbicide programs have become the standard for most Wisconsin corn producers. The apparent time and cost savings in controlling weeds with a single pre or post-emergence herbicide application is the driving force behind this trend. While there are situations where a single pass program will work, it has weaknesses that can result in inconsistent performance.


Site-Specific Tillage Management And Crop Yield Response, Mahdi Al-Kaisi Nov 2006

Site-Specific Tillage Management And Crop Yield Response, Mahdi Al-Kaisi

Proceedings of the Integrated Crop Management Conference

Tillage decision is only one issue farmers have to make during fall. There are many factors that need to be considered in selecting a tillage system for any given field or region within the state. Those factors are soil conditions, which can include, soil slope, soil drainage, top soil depth or the A-horizon depth. Other factors need to be considered, which are equally important. They are management factors, such as, residue cover, type of residue (corn or soybean), soil moisture condition at the time of making the decision, timing of tillage operation, fertilizer management in conjunction with tillage operation, type ...


Weed Management Update - Who Cares?, Micheal D. K. Owen Nov 2006

Weed Management Update - Who Cares?, Micheal D. K. Owen

Proceedings of the Integrated Crop Management Conference

Despite the importance of glyphosate-based crop systems, there is a need for continued investigation and development of new tactics to manage weeds effectively and economically. It is interesting that larger farm size and higher percentage of income attributable to grain is associated with growers willingness to accept alternative weed management strategies and the adoption of integrated weed management programs (Hammond et al. 2006). The concern for timely weed management in order to protect crop yields becomes premiere in POST-based corn and soybean systems, whether based on glyphosate or any other herbicide (Halford et al. 200 l; Cox et al. 2006 ...


Strategies For Management Of Soybean Sudden Death Syndrome And White Mold, X. B. Yang, S. S. Navi Nov 2006

Strategies For Management Of Soybean Sudden Death Syndrome And White Mold, X. B. Yang, S. S. Navi

Proceedings of the Integrated Crop Management Conference

Soybean sudden death syndrome (SDS) caused by Fusarium solani f. sp. glycines and soybean white mold caused Sclerotinia sclerotiorum were two of the most prevalent diseases in 2006. The two diseases have become even year production problems for some producers. This workshop will review results of the latest studies from the past two years and discuss management strategies for the two diseases. The SDS has been recognized as a major disease of soybean (Glycine max (L.) Merrill) in the southern United States for nearly three decades. In 1995 Scherm and Yang using computer model predicted that the disease would become ...


A Postemergence Primer, Bob Hartzler Nov 2006

A Postemergence Primer, Bob Hartzler

Proceedings of the Integrated Crop Management Conference

Postemergence herbicides are the most widely used weed management tool in Iowa's corn and soybean acres. Application of the herbicide directly to the target bypasses the myriad of soil interactions that influence preemergence herbicides. However, killing weeds with postemergence products is not as simple as merely getting the herbicide onto the leaf of the weed. This paper will discuss the factors that influence the activity of postemergence weeds.


Using Resistant Soybean Varieties To Manage Soybean Cyst Nematode, Gregory L. Tylka Nov 2006

Using Resistant Soybean Varieties To Manage Soybean Cyst Nematode, Gregory L. Tylka

Proceedings of the Integrated Crop Management Conference

The soybean cyst nematode (SCN) was a serious yield-limiting pest of soybeans throughout Iowa in 2006. It caused severe damage in areas of Iowa that received less-than-normal rainfall. This nematode is widely distributed throughout the state and does not increase its numbers extraordinarily (i.e. does not flare up) in dry years. The nematode has excellent long-term survival and its population densities build up each year that susceptible soybeans are grown, regardless of the precipitation that occurs. Research in Iowa has shown that up to 40% yield loss can occur without the appearance of any above-ground symptoms.


Managing Nitrogen For High Corn Yields, John E. Sawyer Nov 2006

Managing Nitrogen For High Corn Yields, John E. Sawyer

Proceedings of the Integrated Crop Management Conference

The old saying still holds; yield is king. Producers are interested in high crop yields in order to pay for input costs, cover enterprise expenses, and provide profits. Demand for corn grain is increasing rapidly, with large need for expanding ethanol and livestock production. This demand is fueling interest in higher productivity and more continuous corn (CC). Yields are now commonly topping 200+ bu/acre, and risk of yield loss related to nitrogen (N) management weighs as heavily on the minds of producers as it ever has. What N management practices make sense to sustain high yield in corn following ...


Evaluation Of The Illinois Soil Nitrogen Test In The North Central Region, C. A. M. Laboski, J. E. Sawyer, D. T. Walters, L. G. Bundy, R. G. Hoeft, G. W. Randall, T. W. Andraski Nov 2006

Evaluation Of The Illinois Soil Nitrogen Test In The North Central Region, C. A. M. Laboski, J. E. Sawyer, D. T. Walters, L. G. Bundy, R. G. Hoeft, G. W. Randall, T. W. Andraski

Proceedings of the Integrated Crop Management Conference

Data from 96 locations across the North Central Region was complied to evaluate the usefulness of the Illinois soil nitrogen test (ISNT) in identifying fields where corn will not respond to additional N fertilizer and predicting the yield optimizing N rate (YONR) for each field. The ISNT could not accurately predict non-responsive sites, nor could it predict YONR. Sub-setting the data based on soil drainage class and previous crop did not improve the predictive capability of the ISNT. The ISNT was related to soil organic matter and was measuring a constant fraction of total soil N. The ISNT is not ...


Management Considerations For Continuous Corn Production, Lori Abendroth Nov 2006

Management Considerations For Continuous Corn Production, Lori Abendroth

Proceedings of the Integrated Crop Management Conference

Growing a corn crop after a previous crop of corn on the same ground requires special management. But we've done it before! In 1976, Iowa had around 14 million acres of corn and 6 1/2 million acres of soybean. That is about a 2:1 ratio. The ratio of corn to soybean in 2006 was 55:45 with nearly 13 million acres of corn. We can grow more corn. The question is how to do it without sacrificing yield. Although in some of the better years for growing corn and in some environments in those years yields are ...


Strike Two For Soybean Rust - 2006 In Review, Alison Robertson, X. B. Yang Nov 2006

Strike Two For Soybean Rust - 2006 In Review, Alison Robertson, X. B. Yang

Proceedings of the Integrated Crop Management Conference

Asian soybean rust is caused by the fungus Phakopsora pachyrhizi. This disease was first reported in November 2004 and survived the past two winters on kudzu in the south. Soybean rust can seriously reduce soybean yields and/or significantly increase the cost of soybean production when the disease occurs with high incidence and severity


Forage For Horses: But The Horse Isn't Really The Customer!, Steve Barnhart Nov 2006

Forage For Horses: But The Horse Isn't Really The Customer!, Steve Barnhart

Proceedings of the Integrated Crop Management Conference

Horses are natural grass eaters. Their mouth structure and digestive anatomy allow horses to successfully use forages as a primary source of nutrition and as an important part of normal digestive system function. This requirement for forages is most easily supplied by pasture and hay. Mature horses will generally consume 2 to 2.5 percent of their body weight in feed each day. Ideally, horses should consume l percent or more (as dry matter) of their body weight daily as hay or pastures. Forages can provide varying amounts of the nutrient requirements depending on the forage quality and amount consumed ...


Foliar Fungicide Application Techniques On Soybeans, H. Mark Hanna, Alison Robertson, W. Mark Carlton, Robert E. Wolf Nov 2006

Foliar Fungicide Application Techniques On Soybeans, H. Mark Hanna, Alison Robertson, W. Mark Carlton, Robert E. Wolf

Proceedings of the Integrated Crop Management Conference

Soybeans (Glycine max L.) are a major commodity crop grown on over 29 million hectare (72 million acres) in the United States. A large part of the cropland base in Iowa, 5 million hectare (11 to 13 million acres) annually, is devoted to soybean production. Although long term crop yield trends are upward, soybean yield increases have been more stagnant than corn, the common companion rotational crop, causing growers to question factors such as disease that might be slowing yield growth. In late 2004 Asian Soybean Rust (Phahopsora pachyrhizi) was detected in the United States. Because of the potential for ...


Update Of Soybean Rust Research: What We Have Learned In The Last Two Seasons And How To Position For The Future In Soybean Rust Risk Management, X. B. Yang, Ana Paula Dias, Xun Li Nov 2006

Update Of Soybean Rust Research: What We Have Learned In The Last Two Seasons And How To Position For The Future In Soybean Rust Risk Management, X. B. Yang, Ana Paula Dias, Xun Li

Proceedings of the Integrated Crop Management Conference

In the last two seasons, soybean rust has shown limited dispersal during a growing season in the southern US. In summer, it mainly spread in the Gulf Coast states. Dry weather conditions in past two summers have been considered as a possible reason for the slow development of this disease in the US. The disease did not take off to the further northern states until September. This year it was found in three new states, Illinois, Indiana, and Virginia. So far, it was found 15 states in total242 counties (See the map on right). In Iowa, the disease was not ...


What's New With Micronutrients In Our Part Of The World?, George Rehm Nov 2006

What's New With Micronutrients In Our Part Of The World?, George Rehm

Proceedings of the Integrated Crop Management Conference

The importance of micronutrients for production of a variety of crops in the North-Central region of the U.S. has been recognized for many years. When needed, these essential nutrients can have a substantial positive impact on production. However, neither the need for nor the importance of each micronutrient is universal across the region. Importance (need) is greatly affected by crop, soil properties, and production environment. With traditional thinking over the years, thoughts have focused on band, broadcast, or foliar applications. There are always questions about source and rate. There are, however, some new questions and ideas about the use ...


Dealing With Sulfur Deficiency In Northeast Iowa Alfalfa Production, Brian Lang, John Sawyer, Steve Barnhart Nov 2006

Dealing With Sulfur Deficiency In Northeast Iowa Alfalfa Production, Brian Lang, John Sawyer, Steve Barnhart

Proceedings of the Integrated Crop Management Conference

Historically, sulfur (S) deficiency has not been an issue for crop production in Iowa. Previous research documented sufficient plant available S for crop production on most soil associations (Alesii, 1982). Recent studies in corn and soybean production were consistent with results of previous research conducted across Iowa (Sawyer and Barker, 2002). The exception was a longstanding suggestion to apply S as commercial fertilizer or livestock manure for alfalfa production on sandy soils. However, over the past decade, alfalfa grown on some silt loam and loam soils in northeast Iowa has exhibited a slowly worsening problem with areas in fields of ...


Virus In Your Beans - What To Do?, John H. Hill, Jeff Bradshaw, Marlin Rice Nov 2006

Virus In Your Beans - What To Do?, John H. Hill, Jeff Bradshaw, Marlin Rice

Proceedings of the Integrated Crop Management Conference

Soybean viruses have become an increasing problem in Iowa soybeans since the late 1990's. Losses due to virus disease include both decreased yield and seed quality conferred by mottling of seed coats or hilum bleeding. The principle viruses involved are Bean pod mottle (BPMV) and Soybean mosaic viruses (SMV). Of the two, BPMV has been by far the greater problem in Iowa. Unfortunately, the two viruses cannot be differentiated based upon symptoms. Both viruses cause similar foliar symptoms and seed coat mottling. However, the viruses belong to different virus families and have different insect vectors. The BPMV is primarily ...


Herbicide Resistance, Weed Population Shifts, And Weed Management Stewardship: Is Anything New?, Micheal D. K. Owen Nov 2006

Herbicide Resistance, Weed Population Shifts, And Weed Management Stewardship: Is Anything New?, Micheal D. K. Owen

Proceedings of the Integrated Crop Management Conference

As glyphosate-resistant soybean and corn production systems are becoming the standard for Iowa and the Midwest, the selection pressure imposed on the agro-ecosystem by glyphosate is likely increasing at an increasing rate. World-wide, ll weed species have been reported as having evolved glyphosate-resistant biotypes (Heap 2006). Nine of the glyphosate-resistant biotypes were reported after 2000, and four glyphosate-resistant biotypes were reported in 2005. It is clear that the evolution of glyphosate-resistant weeds is increasing at an increasing rate. While ISU reported the existence of glyphosate-resistant common waterhemp in 1998, the relative economic importance of glyphosate-resistant weed biotypes in Iowa has ...


A Long-Term Look At Crop Rotation On Corn Yield And Response To Nitrogen Fertilization, Antonio P. Mallarino, Enrique Ortiz-Torres Nov 2006

A Long-Term Look At Crop Rotation On Corn Yield And Response To Nitrogen Fertilization, Antonio P. Mallarino, Enrique Ortiz-Torres

Proceedings of the Integrated Crop Management Conference

Increasing concerns about fertilizer nitrogen (N) cost, public awareness of effects of excess N use on water quality, and corn after corn production in Iowa require a better understanding of long-term effects of N fertilization and cropping sequences on corn yield. Therefore, continuous research and management adjustments are needed to improve economic benefits from fertilization and water quality. Growing corn in rotation with grain or forage legumes reduces the need of N fertilizer compared with continuous corn because soil after legume crops have higher potential N availability than after corn. Previous research has shown that optimum N fertilization rates for ...


Variable-Rate Application For Phosphorus And Potassium: Impacts On Yield And Nutrient Management, Antonio P. Mallarino, David J. Wittry Nov 2006

Variable-Rate Application For Phosphorus And Potassium: Impacts On Yield And Nutrient Management, Antonio P. Mallarino, David J. Wittry

Proceedings of the Integrated Crop Management Conference

Soil fertility management can be improved by use of precision agriculture technologies. Global positioning systems (GPS), yield monitors, various forms of remote sensing, geographical information system (GIS) software, and variable-rate technology (VRT) are available for use by producers. Dense soil sampling, crop scouting, and other practices complete the new technological package. Soil testing is a diagnostic tool especially adapted for site-specific management. At the same time, GPS and GIS can greatly improve soil testing when these technologies are used to better describe nutrient levels across a field. The spatial variation of plant nutrients over a field makes soil sampling the ...