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Iowa State University

Plant Sciences

Proceedings of the Integrated Crop Management Conference

2009

Articles 1 - 21 of 21

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Corn Planting Date: Understanding Plant Grwoth And Yield Response, Lori J. Abendroth, Anthony J. W. Myers, Roger W. Elmore Dec 2009

Corn Planting Date: Understanding Plant Grwoth And Yield Response, Lori J. Abendroth, Anthony J. W. Myers, Roger W. Elmore

Proceedings of the Integrated Crop Management Conference

Research was conducted to equip Iowa producers with more accurate corn planting date information based on their specific location. Objectives for this research project addressed during the presentation include: 1. What are the optimum planting windows for maximum yield? 2. How do new recommendations (2006-2009 data) compare to previous ISU recommendations (1998-2000 data)? 3. What are the risks associated with planting outside the optimum window? 4. How is plant growth and development impacted by varying planting dates? 5. Are grain yield differences correlated with differences in growth and development?


Impact Of Fungicide-Insecticide Tank Mixes On Soybean In Iowa, Rebekah Ritson, Nathan Bestor, Alison Robertson, Matt O'Neal Dec 2009

Impact Of Fungicide-Insecticide Tank Mixes On Soybean In Iowa, Rebekah Ritson, Nathan Bestor, Alison Robertson, Matt O'Neal

Proceedings of the Integrated Crop Management Conference

In recent years, growing concern about invasive pests such as soybean aphid (Aphis glycines) and soybean rust (Phakopsora pachyrhizi) has led to dramatic increases in pesticide use on soybean. Both pests pose a serious threat to the industry, with untreated outbreaks of soybean aphid capable of reducing yields by 14-50% and reports of soybean rust resulting in yield losses of 10-80%. Many agribusinesses are now offering growers a pest management program emphasizing a calendar-based, co-application of a fungicide-insecticide tank mix. However, it is unclear if these co-application methods exhibit improvement upon current recommendations, which apply pesticides only when needed.


Corn Nematodes And Soybean Cyst Nematode: Basic Facts And Prospects For 2010, Gregory L. Tylka Dec 2009

Corn Nematodes And Soybean Cyst Nematode: Basic Facts And Prospects For 2010, Gregory L. Tylka

Proceedings of the Integrated Crop Management Conference

Nematodes are microscopic worms. Many nematode species live in the soil, and some soil-dwelling nematodes feed on plant roots. These plant-parasitic nematodes can cause considerable damage and yield loss when population densities (numbers) become high.


Review Of The 2009 Growing Season From A Plant Pathologist's Perspective, Alison Robertson Dec 2009

Review Of The 2009 Growing Season From A Plant Pathologist's Perspective, Alison Robertson

Proceedings of the Integrated Crop Management Conference

From a plant pathologist perspective, 2009 was a great year for disease! The 2009 growing season was characterized by cool temperatures, thus growing degree days lagged behind normal. South east and east central Iowa received above average precipitation but western and northern Iowa were drier than normal.


Agronomics Of High-Yielding Corn, Emerson D. Nafziger Dec 2009

Agronomics Of High-Yielding Corn, Emerson D. Nafziger

Proceedings of the Integrated Crop Management Conference

Corn yields in the Corn Belt have been increasing steadily, with the state average yield in Illinois rising at a rate of 1.9 bushels per acre per year from 1970 to 2009, but 3.6 bushels per acre per year since 1996. With few exceptions, the weather during the past 15 years has been very favorable for corn. But improvements in hybrids and in management have played an important part in these yield increases as well.


(Mis)Managing Data: How To Get The Results You Want!, Jim Rouse Dec 2009

(Mis)Managing Data: How To Get The Results You Want!, Jim Rouse

Proceedings of the Integrated Crop Management Conference

Selecting corn hybrids and soybean varieties is often cited as one of the most important factors in maximizing yield potential. Generally there is no shortage of performance data, all promising to help make your decisions easier, or even to make your decisions FOR you!


The Evolution Of Herbicide Resistant Weeds In Iowa: Description, Implications, And Solutions, Micheal D. K. Owen Dec 2009

The Evolution Of Herbicide Resistant Weeds In Iowa: Description, Implications, And Solutions, Micheal D. K. Owen

Proceedings of the Integrated Crop Management Conference

There has been concern about the evolution of glyphosate resistance in some Iowa weeds for many years although the field-wide existence of any problems has not been previously reported. It is important to recognize that in reality, common waterhemp (Amaranthus rudis*) with resistance to glyphosate was reported in fields near Everly and Badger, Iowa as early as 1998 (Zelaya and Owen 2002). However, the likelihood of weeds evolving resistance to herbicides pre-dates glyphosate-resistant weed biotypes by five decades (Harper 1956). The first identification of herbicide resistant weed biotypes pre-dates glyphosate-resistance by four decades (Ryan 1970) and currently there 19 herbicide ...


Dealing With Sulfur Deficiency In Iowa Corn Production, John Sawyer, Brian Lang, Dan Barker, George Cummins Dec 2009

Dealing With Sulfur Deficiency In Iowa Corn Production, John Sawyer, Brian Lang, Dan Barker, George Cummins

Proceedings of the Integrated Crop Management Conference

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 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 was ...


Hay Harvest Decisions And Management, Stephen K. Barnhart Dec 2009

Hay Harvest Decisions And Management, Stephen K. Barnhart

Proceedings of the Integrated Crop Management Conference

Most forage crops managed for hay or silage in the upper Midwest U.S. are composed of perennial grasses and/or legumes. Their growth during a typical growing season often allows for multiple harvests. Forage species and varieties have a great influence on the number of harvests and the nutritive quality of the harvested crop. Additionally, the stage of maturity when harvested, fertilization management, harvest practices and weather will also influence, yield, nutritive quality and persistence of these forage stands.


The Northwest Iowa On-Farm Research Project, Joel Dejong, Josh Sievers Dec 2009

The Northwest Iowa On-Farm Research Project, Joel Dejong, Josh Sievers

Proceedings of the Integrated Crop Management Conference

ISU Extension, the Iowa Corn/Soybean Initiative, ISU Research and Demonstration farms and the NW Iowa Experimental Association partnered together to form the Northwest Iowa On-farm Research project which is now in its 5th year in Lyon, Sioux and Osceola Counties in the NW corner of Iowa. The goals of this project are to implement on-farm research projects that are beneficial to the cooperator and other NW Iowa farmers; to cooperate with producers to provide up-to-date research that affects their operation; and to provide unbiased, statistically analyzed data for farmers on compared production practices. We want to answer the crop ...


Soybean Production: Little Things That Can Make A Difference, Seth Naeve, Robert W. Kluver Iii, Rob Proulx, Jodi Dejong Hughes Dec 2009

Soybean Production: Little Things That Can Make A Difference, Seth Naeve, Robert W. Kluver Iii, Rob Proulx, Jodi Dejong Hughes

Proceedings of the Integrated Crop Management Conference

While some are working on hitting home runs, many of our research projects are focused around getting on base. This presentation will focus on strategies to minimize harvest losses through managing the height of the lowest pod, understanding the risks and rewards of planting long season varieties, maximizing harvest efficiency with rock rollers, and management and environmental effects on soybean seed quality. While this paper presents data assembled in 2008 and earlier, the presentation will include new crop data.


The Cost Of Convenience: The Impact Of Weeds On Crop Yields, Bob Hartzler Dec 2009

The Cost Of Convenience: The Impact Of Weeds On Crop Yields, Bob Hartzler

Proceedings of the Integrated Crop Management Conference

Populations of weeds capable of affecting crop yields are present in every field during every year. Perhaps it is the ubiquitous nature of weeds that leads to the complacency in their management across Iowa and the Midwest. A survey of Wisconsin corn and soybean fields found that weeds were managed in a way that resulted in yield losses in more than 10% of surveyed fields, with an average yield loss of slightly less than 10%.


Crop Weather Risk For 2010, Elwynn Taylor Dec 2009

Crop Weather Risk For 2010, Elwynn Taylor

Proceedings of the Integrated Crop Management Conference

The Midwest has just experienced two harsh winters in a row, a wet Spring, lagging Growing Degree Days, slow development of crops, record high yield in the field, Fall rain (and floods), and record moist grain and soy at harvest. Although there are a few who do remember when everyone helped with harvest AFTER Thanksgiving Dinner, most of us were convinced that it was better equipment that got the crops in. It turns out that weather may have had an impact all along.


Tillage And Cover Crop Effects On Productivity, Soil Properties, And Nitrate Leaching, Mahdi Al-Kaisi, Greg Wilson Dec 2009

Tillage And Cover Crop Effects On Productivity, Soil Properties, And Nitrate Leaching, Mahdi Al-Kaisi, Greg Wilson

Proceedings of the Integrated Crop Management Conference

Nitrate (NO3-N) pollution in rivers and streams from surface runoff and leaching to groundwater is a major problem across the United States (Nolan et al., 1998; Burkart and James, 1999; USGS, 2001) and Iowa as well. Previous work (Keeney, 1989; Burkart and James, 1999; Schilling and Libra, 2000) indicates that agricultural land use has been identified as the main contributor to the NO3-N load in our rivers and streams. The high mobility of NO3-N makes it readily available for leaching through the soil profile, especially during the periods when no active plant growth is taking place between harvest and planting ...


Dicamba And Soybeans: A Controversial Combo, Chris Boerboom Dec 2009

Dicamba And Soybeans: A Controversial Combo, Chris Boerboom

Proceedings of the Integrated Crop Management Conference

Iowa corn and soybean growers have had a long history of working with the herbicide dicamba, the active ingredient that was originally sold as Banvel. In fact, dicamba was registered 42 years ago. During this time, corn growers have frequently used dicamba products to effectively manage many broadleaf weeds in corn with either preemergence or early postemergence applications. However, growers have also learned that soybeans are highly sensitive to dicamba. With the adoption of glyphosate-resistant corn hybrids and the availability of new corn herbicides, growers and applicators may be inclined to think that worries about dicamba are history. Nevertheless, situations ...


Managing Soybean Sudden Death Syndrome And White Mold, X. B. Yang, S. S. Navi Dec 2009

Managing Soybean Sudden Death Syndrome And White Mold, X. B. Yang, S. S. Navi

Proceedings of the Integrated Crop Management Conference

The cool 2009 growing season resulted in a challenging disease management year for soybean growers. The long wet planting season followed by a record cool July was ideal for disease occurrence. It was the first time that two soybean diseases, sudden death syndrome (SDS) and soybean white mold, were wide spread in the same season in Iowa, as well other states. In August, SDS showed up almost in every area in Iowa with some regions having high intensity. Large patches of soybean with SDS symptom were obvious from south to north. Into late August, white mold gained attention as producers ...


Weed Management Update 2010, Micheal D. K. Owen Dec 2009

Weed Management Update 2010, Micheal D. K. Owen

Proceedings of the Integrated Crop Management Conference

Weed management in 2009 was, as usual, a mixed vision of apparent successes and obvious failures. In general, less than complete planning left many producers in dire straits for weed management options after planting. Wet conditions precluded many planned programs and thus once again, untold yield potential was lost due to weed interference. While the postemergence (POST) herbicide applications were generally successful (in killing weeds), it is clear that Iowa fields are becoming more populated by weeds that do not respond to the “programs of choice”. Furthermore, the widespread lack of using an herbicide strategy that includes a residual herbicide ...


Providing Service And Suport To Watershed Improvement Projects Accress Iowa, Jamie Benning, Chad Ingels Dec 2009

Providing Service And Suport To Watershed Improvement Projects Accress Iowa, Jamie Benning, Chad Ingels

Proceedings of the Integrated Crop Management Conference

Nonpoint source nutrient pollution from agriculture entering Iowa’s surface water bodies (Figure 1) is a problem for impaired local watersheds throughout the Corn Belt, and as far away as the Gulf of Mexico. The Mississippi River drains 40 percent of the continental US and carries almost 140 cubic miles of water yearly (Libra 1998). The U.S. Geological Survey estimated an average of 1.65 million tons/year of nitrogen (N) were exported into the Gulf of Mexico from 1987-1996 causing a condition called hypoxia (Libra 1998). Hypoxia, also known as a dead zone, is an area where water ...


Do New Corn Hybrids And Yield Levels Influence Potassium Fertilizer Management?, Antonio P. Mallarino, Matthew W. Clover Dec 2009

Do New Corn Hybrids And Yield Levels Influence Potassium Fertilizer Management?, Antonio P. Mallarino, Matthew W. Clover

Proceedings of the Integrated Crop Management Conference

The frequency of potassium (K) deficiency symptoms in corn has increased in recent years. Observations in Iowa and neighboring states have shown that the reason for these symptoms was a low soil K level in about two-thirds of the instances reported. In the rest of the instances, however, the K deficiency symptoms resulted from a variety of reasons related to limitations in root growth or water uptake and/or K uptake by plants. It is known that factors that limit root activity and growth greatly inhibit K uptake and yield because K is a relatively immobile nutrient in soils. A ...


Impact Of Hail Damage On Grain Quality, Alison Robertson, Gary Munkvold, Charles Hurburgh, Steve Ensley Dec 2009

Impact Of Hail Damage On Grain Quality, Alison Robertson, Gary Munkvold, Charles Hurburgh, Steve Ensley

Proceedings of the Integrated Crop Management Conference

Two large and severe hail storms occurred in Iowa during the 2009 growing season. The first occurred on July 24, 2009 in northeast Iowa and caused damage to over 400,000 crop acres, with at least 10 percent of this acreage receiving around 100 percent yield loss. The second storm occurred on August 9, 2009. This storm travelled approximately 150 miles, from Western Sac and Ida counties to Eastern Grundy county. This hail swath was about 10 miles wide, between highways IA175 and US20, with 3 miles in the middle being almost completely lost. In both storms, the stones were ...


Reemergence Of Goss's Bacterial Wilt And Blight Of Corn In The Midwest States, Tamra A. Jackson, Kevin A. Korus Dec 2009

Reemergence Of Goss's Bacterial Wilt And Blight Of Corn In The Midwest States, Tamra A. Jackson, Kevin A. Korus

Proceedings of the Integrated Crop Management Conference

Goss’s wilt and blight was first identified in Dawson County in south central Nebraska in 1969 (Claflin, 1999). Over the next 10 years, the disease was identified in 53 additional counties in the state and in at least one county in five of the six states bordering Nebraska (Vidaver et al., 1981). After some debate over the name of the disease, if was finally named after R. W. Goss, an earlier chair of the Department of Plant Pathology and first full-time Dean of the Graduate College at the University of Nebraska. Resistance was successfully incorporated into commercial hybrids and ...