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Iowa State University

Plant Sciences

Proceedings of the Integrated Crop Management Conference

2016

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Update On Soybean Diseases And Their Management, Daren Mueller Dec 2016

Update On Soybean Diseases And Their Management, Daren Mueller

Proceedings of the Integrated Crop Management Conference

There were several diseases that appeared in soybean fields in 2016. While diseases were not common early in the season, by late July they became more prevalent. Some of the most prevalent diseases during the 2016 season were bacterial pustule, frogeye leaf spot, sudden death syndrome (SDS), and white mold. This talk will focus on these specific diseases and provide updates on management of soybean diseases in general.


Understanding And Increasing Soybean Yields, Ryan J. Van Roekel, Larry C. Purcell Dec 2016

Understanding And Increasing Soybean Yields, Ryan J. Van Roekel, Larry C. Purcell

Proceedings of the Integrated Crop Management Conference

An understanding of the main factors influencing grain yield in soybean can provide key insights for making management decisions to increase yield. Seed number is determined by the amount of photosynthate produced between R1 and R5 that is allocated to the seeds, divided by the minimum amount of photosynthate needed to keep a single seed from aborting. Stresses or improvements in crop growth prior to flowering should not have a significant impact on final yield, provided that >95% light interception is achieved by R1. Seed weight is determined by the seed growth rate and the length of the seed fill ...


Nitrogen Myths And Realities, Michael Castellano, Sotirios Archontoulis, Carolina Cordova, Ranae Dietzel Dec 2016

Nitrogen Myths And Realities, Michael Castellano, Sotirios Archontoulis, Carolina Cordova, Ranae Dietzel

Proceedings of the Integrated Crop Management Conference

More than 1/3 of the nitrogen in human bodies is derived from industrially synthesized nitrogen fertilizer (Smil, 2004). Without nitrogen fertilizer, agriculture could not sustain the global population of 7 billion people living today, much less the 11 billion people expected to be living by 2100. There is no doubt: nitrogen fertilizer is critical to sustain human health and grow developing economies.


Iowa Soybean Association And Iowa State University Cooperative Soybean Cyst Nematode And Corn Rootworm Beetle Survey Results, Tristan Mueller, Clarke Mcgrath Dec 2016

Iowa Soybean Association And Iowa State University Cooperative Soybean Cyst Nematode And Corn Rootworm Beetle Survey Results, Tristan Mueller, Clarke Mcgrath

Proceedings of the Integrated Crop Management Conference

In cooperation with industry partners, Iowa Soybean Association and Iowa State University (ISU) conducted soybean cyst nematode and corn rootworm surveys across the state. With nearly every county in the state included in the surveys, the results have been informative.


Understanding The 2016 Yields And Interactions Between Soils, Crops, Climate And Management, Sotirios Archontoulis, Mark Licht, Mike Castellano, Ranae Dietzel, Andy Van Loocke, Raziel Ordonez, Javed Iqbal, Laila Puntel, Carolina Cordova, Kaitlin Togliatti, Rafael A. Martinez-Feria, Huber Isaiah, Matt Helmers Dec 2016

Understanding The 2016 Yields And Interactions Between Soils, Crops, Climate And Management, Sotirios Archontoulis, Mark Licht, Mike Castellano, Ranae Dietzel, Andy Van Loocke, Raziel Ordonez, Javed Iqbal, Laila Puntel, Carolina Cordova, Kaitlin Togliatti, Rafael A. Martinez-Feria, Huber Isaiah, Matt Helmers

Proceedings of the Integrated Crop Management Conference

Several technologies to forecast crop yields and soil nutrient dynamics have emerged over the past years. These include process-based models, statistical models, machine learning, aerial images, or combinations. These technologies are viewed as promising to assist Midwestern agriculture to achieve production and environmental goals, but in general, most of these technologies are in their initial stages of implementation. In June 2016 we launched a web-tool (http://crops.extension.iastate.edu/facts/) that provided real-time information and yield predictions for 20 combinations of crops and management practices. Our project, which is called FACTS (Forecast and Assessment of Cropping sysTemS), takes a ...


What Happens During Pathogen Infections In Crop Plants?, Steve Whitham Dec 2016

What Happens During Pathogen Infections In Crop Plants?, Steve Whitham

Proceedings of the Integrated Crop Management Conference

Plants have sophisticated immune systems that provide protection against most microorganisms. However, pathogens that are able cause disease have the ability to disrupt plant defenses. Recent research has shown that there is extensive communication between plants and microorganisms, and that there are multiple layers to effective disease resistance. This presentation will introduce the audience to concepts in plant disease resistance and the offensive weapons that pathogens use as they attempt to overcome plant defenses.


Value Of Tissue Testing To Improve Phosphorus, Potassium, And Micronutrients Management For Corn And Soybean, Antonio P. Mallarino Dec 2016

Value Of Tissue Testing To Improve Phosphorus, Potassium, And Micronutrients Management For Corn And Soybean, Antonio P. Mallarino

Proceedings of the Integrated Crop Management Conference

Soil testing is a useful and commonly used diagnostic tool for making phosphorus (P) and potassium (K) fertilization decisions. Soil testing for micronutrients also is useful, but its value is more uncertain because of more complex and less understood soil processes that affect their availability for crops.


Long-Term Tillage And Crop Rotation Effects On Soil, Yield And Economic Returns, Mahdi Al-Kaisi, David Kwaw-Mensah, Sotirios Archontoulis Dec 2016

Long-Term Tillage And Crop Rotation Effects On Soil, Yield And Economic Returns, Mahdi Al-Kaisi, David Kwaw-Mensah, Sotirios Archontoulis

Proceedings of the Integrated Crop Management Conference

Corn (Zea mays L.) and soybeans (Glycine max (L.) Merr.) are major annual crops grown in yearly rotation in Iowa. The economic returns of both crops with different tillage systems and crop rotations are highly influenced by regional soil and climate conditions. This study was conducted at seven locations in Iowa from 2003 to 2013 with the objectives to: (i) investigate seasonal variability in corn and soybean yields as affected by tillage and crop rotation, (ii) identify appropriate tillage system for each crop rotation and location, and (iii) evaluate the magnitude of crop rotation effect on the yields and economic ...


Fungicide Selection And Timing To Manage Southern Rust Of Corn, Travis Faske Dec 2016

Fungicide Selection And Timing To Manage Southern Rust Of Corn, Travis Faske

Proceedings of the Integrated Crop Management Conference

Foliar corn diseases are among the most important yield-limiting factors that affect commercial corn production in the Mid-South. Southern rust is caused by the fungus Puccinia polysora, which only infects corn and is reintroduced each year from the tropic regions of Central America and the Caribbean. Symptoms consist of small orange pustules that are often first detected on leaves located in the mid- to upper-canopy. As conditions favor disease development initial infections produce spores that are spread to nearby plants and nearby fields resulting in secondary infections and the spread of southern rust.


Impact Of Nitrogen Application Timing On Corn Production, John E. Sawyer, Daniel W. Barker, John P. Lundvall Dec 2016

Impact Of Nitrogen Application Timing On Corn Production, John E. Sawyer, Daniel W. Barker, John P. Lundvall

Proceedings of the Integrated Crop Management Conference

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 preplant N application (SP 0435A).


Herbicide Resistance: Experiences East Of The Mississippi River, Aaron G. Hager Dec 2016

Herbicide Resistance: Experiences East Of The Mississippi River, Aaron G. Hager

Proceedings of the Integrated Crop Management Conference

The continual evolution of weed species and populations resistant to herbicides from one or more mechanism-of-action families represents one of the most daunting challenges faced by weed management practitioners. Waterhemp has evolved resistance to more herbicide mechanisms of action than any other Illinois weed species, including resistance to inhibitors of acetolactate synthase (ALS), photosystem II (PSII), protoporphyrinogen oxidase (PPO), enolpyruvyl shikimate-3-phosphate synthase (EPSPS) and hydroxyphenyl pyruvate dioxygenase (HPPD). Not every individual waterhemp plant is r esistant to one or more herbicides, but the majority of field-level waterhemp populations contain one or more types of herbicide resistance. Perhaps even more daunting ...


Soybean Cyst Nematode: Challenges And Opportunities For Sustained, Profitable Soybean Production, Gregory Tylka Dec 2016

Soybean Cyst Nematode: Challenges And Opportunities For Sustained, Profitable Soybean Production, Gregory Tylka

Proceedings of the Integrated Crop Management Conference

The soybean cyst nematode (SCN), Heterodera glycines, continues to be a widespread and damaging pathogen of soybean. The pest has been found in all soybean-producing states except New York and all Iowa counties except Allamakee (Figure 1). Although the nematode has been present in the Midwest for four decades, the situation with SCN continues to evolve.


Automated Soil Sampling Machines Provide Different Results Compared To Hand Sampling, Scott Nelson Dec 2016

Automated Soil Sampling Machines Provide Different Results Compared To Hand Sampling, Scott Nelson

Proceedings of the Integrated Crop Management Conference

Soil sampling to characterize levels of soil fertility is one of the foundations of profitable management. Soil fertility below optimum levels reduces yield potential, while soil fertility above optimum levels results in lost opportunity costs, profits and potential environmental degradation. In site specific fertility management, soil testing is especially important as it is the basis upon which variable rate prescriptions are written.


Interaction Of Weather And Field Variability On Profitability In Crop Production, Suzanne Fey, Peter Kyveryga, Jensen Connor Sr., Adam Kiel, David Muth Dec 2016

Interaction Of Weather And Field Variability On Profitability In Crop Production, Suzanne Fey, Peter Kyveryga, Jensen Connor Sr., Adam Kiel, David Muth

Proceedings of the Integrated Crop Management Conference

The objective of this study was to quantify the often substantial yet somewhat elusive impact of weather, management, and soil spatial variability on within-field profitability in corn and soybean crop production using profitability indices such as profit (net return) and return-on-investment (ROI). We analyzed yield and cropping system data provided by 42 farmers within Central and North Eastern Iowa from 2007 to 2014. The dataset was comprised of 380 site years from 77 fields. Commercial software was used to calculate spatial net return (profit) in crop production, ROI, and standard deviation in profit over time for individual fields. Iowa State ...


How Can Fertilizer And Manure Management Practices Reduce Dissolved Phosphorus Loss From Fields And Improve Water Quality?, Antonio P. Mallarino, Mazhar U. Haq Dec 2016

How Can Fertilizer And Manure Management Practices Reduce Dissolved Phosphorus Loss From Fields And Improve Water Quality?, Antonio P. Mallarino, Mazhar U. Haq

Proceedings of the Integrated Crop Management Conference

Phosphorus (P) usually is the nutrient that limits and controls algae growth and eutrophication in freshwater bodies. Public concerns about agriculture impacts on water quality and the likelihood of further government regulation have been increasing.


Crop Weather Outlook 2017 And Beyond, Elwynn Taylor Dec 2016

Crop Weather Outlook 2017 And Beyond, Elwynn Taylor

Proceedings of the Integrated Crop Management Conference

The 2017 crop year follows two years of the 3rd strongest El Niño event since 1950. Historically, very strong El Niño events have only a 25% chance of being followed by a poor crop year. However, there are other factors in play that point to an increasing risk of adverse crop weather during the coming eight years.


Cover Crops 101: Tips And Tricks For Getting Started, Mark Licht Dec 2016

Cover Crops 101: Tips And Tricks For Getting Started, Mark Licht

Proceedings of the Integrated Crop Management Conference

Cover crops are frequently being promoted for the impact they have on reducing nutrient and sediment losses as well as improving soil health. There is no doubt that this is the case. Research across the United States has repeatedly proven these benefits. As a result, interest in cover crop use has risen dramatically over the last decade. However, such interest has not lead to widespread adoption of cover crops in Iowa. In 2015 it was estimated that approximately 500,000 acres of cover crops were planted in Iowa. That’s less than a half percent of the row-crop acres. Poor ...


Is Rna Interference The Next Big Thing In Crop Protection?, Peter Goldsbrough Dec 2016

Is Rna Interference The Next Big Thing In Crop Protection?, Peter Goldsbrough

Proceedings of the Integrated Crop Management Conference

In 1994 the Flavr Savr tomato was the first transgenic plant to be grown commercially in the United States. These tomatoes were developed by Calgene to have improved taste and longer shelf life compared to the conventional tomatoes available in the supermarket at that time. The ripening process was altered by silencing a gene using “antisense RNA”. The scientists who developed the Flavr Savr tomato, and many other biotechnologists who were attempting to modify plants at that time, did not understand the details of how antisense RNA functioned. It would take a few more years before the mechanism was elucidated ...


Palmer Amaranth: It’S Here, Now What?, Bob Hartzler, Meaghan Anderson Dec 2016

Palmer Amaranth: It’S Here, Now What?, Bob Hartzler, Meaghan Anderson

Proceedings of the Integrated Crop Management Conference

Palmer amaranth and waterhemp are two dioecious pigweed species native to North America. Waterhemp’s original range was the western Corn Belt, including Iowa, whereas Palmer amaranth originally inhabited the southwestern United States. Palmer amaranth began to spread to the southeastern United States early in the 20th century but was not listed among the most troublesome weeds of the Southeast until the late 1980s. Interestingly, this is the same time frame that waterhemp emerged as a serious management issue in Iowa and surrounding states. This paper will review the history of Palmer amaranth in Iowa, factors that contribute to its ...


Is There Loss Of Corn Dry Matter In The Field After Maturity?, Charles Hurburgh, Philip Blake, Mark Licht, Mark Hanna Dec 2016

Is There Loss Of Corn Dry Matter In The Field After Maturity?, Charles Hurburgh, Philip Blake, Mark Licht, Mark Hanna

Proceedings of the Integrated Crop Management Conference

Mystery yield loss, phantom yield loss, and now invisible yield loss – all are terms used for the concept that dry matter (yield) is being lost in-field between maturity (at about 28% moisture) and harvest (approximately 15% moisture). Popular press articles continue to indicate up to 1% dry matter loss per 1% grain moisture decrease. If this amount of dry matter loss occurs it would be significant in marketing terms. Some believe that this loss is caused by seed respiration.


Spray Equipment Operation For Emerging Herbicide Technology, H. Mark Hanna Dec 2016

Spray Equipment Operation For Emerging Herbicide Technology, H. Mark Hanna

Proceedings of the Integrated Crop Management Conference

Weed resistance to herbicide is prompting applicators to consider using a broader spectrum of herbicides. Reassessing use of existing herbicides and shifting away from predominant use of a single herbicide such as glyphosate is a sort of “back-to-the-future” approach as long-time applicators and those involved with crop production reacquaint themselves with application requirements of other products. Opportunities for confusion exist as label requirements have changed for variations of once familiar products.


Trends In Diversity And Relative Toxicity Of Herbicide Use In The United States, Andrew R. Kniss Dec 2016

Trends In Diversity And Relative Toxicity Of Herbicide Use In The United States, Andrew R. Kniss

Proceedings of the Integrated Crop Management Conference

Herbicides are a powerful weed control tool for farming operations around the world. A perceived overreliance on herbicides for weed control has sparked much debate on how to best incorporate herbicides into sustainable weed management systems. To have an informed discussion on the future of herbicide use, it is important to understand current and past trends. There is increasing public interest in how herbicide use has changed over time, and whether those changes have positively or negatively affected evolution of herbicide resistant weeds as well as human and environmental health. Risk analysis is complex even when considering only a single ...


Weed Management For 2017 And Beyond, Micheal D. K. Owen Dec 2016

Weed Management For 2017 And Beyond, Micheal D. K. Owen

Proceedings of the Integrated Crop Management Conference

It has been approximately 30 years since the last new herbicide mechanism of action (MOA) was introduced and it is unlikely that a new MOA will be introduced in the near future. Furthermore, weed management issues continue to escalate, particularly the increasing number of herbicide-resistant weed populations and the increasing population densities in fields with herbicide-resistant weeds. For example, in Iowa, multiple resistance in waterhemp is the norm rather than the exception and the rate of spread is accelerating. The recent wide spread introduction of Palmer amaranth in Iowa further contributes to future weed problems. Regardless, farmers in Iowa remain ...


New And Re-Emerging Diseases Of Corn, Alison Robertson Dec 2016

New And Re-Emerging Diseases Of Corn, Alison Robertson

Proceedings of the Integrated Crop Management Conference

There are over 80 diseases described on corn worldwide (Munkvold and White, 2016). Approximately half of these diseases have been described in Iowa. Some diseases, such as gray leaf spot, northern corn leaf blight and anthracnose stalk rot have been prevalent for decades. Some diseases, such as Physoderma brown spot and Goss’s wilt, have re-emerged within the past few years. And then we have new diseases being reported such as tar spot and bacterial leaf streak.


A Practical Look At Disease Management In Alfalfa Production, Brian Lang Dec 2016

A Practical Look At Disease Management In Alfalfa Production, Brian Lang

Proceedings of the Integrated Crop Management Conference

When I ask most farmers about disease management in alfalfa, first thoughts are usually about foliar fungicides, followed by why a stand winterkilled, and sometimes why the new seeding failed. I believe that response is quite understandable relative to what they hear with marketing, and see when it’s time to rotate an old stand or establish a new one. However, as with many crops, disease management in alfalfa clearly starts with variety selection. Second is to minimize stress using appropriate management practices. These practices include adequate soil pH and fertility, proper stand establishment practices, timely harvest management during both ...


Daily Erosion Project: Daily Estimates Of Soil Erosion And Water Runoff, Richard Cruse, Brian Gelder, David James, Daryl Herzmann Dec 2016

Daily Erosion Project: Daily Estimates Of Soil Erosion And Water Runoff, Richard Cruse, Brian Gelder, David James, Daryl Herzmann

Proceedings of the Integrated Crop Management Conference

Soil erosion and water runoff drive water quality degradation and are liabilities to crop production, yet their magnitude is neither quantified nor inventoried for US agricultural areas. This project’s goals are to: (1) estimate soil erosion and surface runoff across the Upper Midwest as contributors to soil and water degradation and (2) inventory these quantities for the next several years.