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2/22/2010 - 2/28/2010

Manure Stewardship: Late Winter Manure Application and Risk

Angela Rieck-Hinz, Extension Program Specialist, Department of Agronomy

There are many definitions of stewardship, but a basic definition is “the responsibility to care for resources.” When applying the term stewardship to manure management we could define it as the “responsibility to collect, transport and apply manure to meet crop nutrient needs while minimizing impacts on resources.”

Manure application timing is a big part of stewardship and one concern with timing is the application of manure in late winter. In the most basic terms – manure should not be applied at this time of year. This statement applies to all sources of manure.

As we head into late winter most of Iowa has significant snow cover. With the warming trend that is predicted for the first week in March, it is likely we will lose significant snow and with the snow loss comes a very high risk of losing the manure with the snow. Nutrient loss from runoff can be significant thereby rendering those manure nutrients useless for crop production and consequently causing stream and surface water pollution. If we are going to use manure as a nutrient source for crop production then we should consider protecting that nutrient investment at all costs by limiting the risk of nutrient runoff. 

With that being said, there will be people who continue winter application of manure, and for a variety of reasons. If you must apply manure in late winter:

• Consider applying on flat slopes.
• Apply as far away from surface waters as possible.
• Follow all required separation distances.
• Avoid application on areas that drain to surface tile inlets. 
• Do not apply manure in a grassed waterway. 
• Wait until the snow melts.
• Avoid application prior to predicted rainfall, snow of warming conditions that could cause snow to melt or runoff.  

Please see IMMS, Volume 3 “Winter Manure Application” at  for additional guidelines.

Be aware that application of liquid manure from confinement feeding operations is prohibited on snow-covered and frozen ground from now until April 1 unless an emergency exemption applies or the manure can be appropriately incorporated into the soil.

Finally, if you participate in USDA-NRCS cost-share programs or receive technical assistance from USDA-NRCS, be aware that the 590 Nutrient Management Standard does not allow nutrient application if runoff potential exists unless you meet the emergency exemptions in the 590 standard. The 590 standard applies to all sources of nutrients, not just manure.


Angela Rieck-Hinz is an extension program specialist for Iowa State University Extension and is the coordinator of the Iowa Manure Management Action Group (IMMAG). Rieck-Hinz can be reached at (515) 294-9590 or by emailing

Interactive Webinar to Focus on Grain Storage and Marketing Issues

By Charles Hurburgh, Department of Agricultural and Biosystems Engineering

The Southeast Iowa Ag Research Association annual meeting on March 4 will include an interactive webinar conducted by the Iowa Grain Quality Initiative titled, Grain Storage and Marketing Issues: 2009 Crop Quality and New GMOs. This interactive webinar, led by Charles Hurburgh, ISU Extension agricultural engineer, will cover the difficult grain storage situation that was created by 2009 corn crop quality. It will address what grain managers should be doing now as we go into warmer weather, and the future prospects for corn storage challenges, as corn production continues to rapidly increase. 

Participants will be able to send written questions during the webinar from their computer terminals. Southeast Iowa meeting attendees will participate from the meeting site at the Washington County extension office in Washington. Anyone else may enter the webinar through the link

The March 4 webinar will start at 11:15 a.m. The session will end at noon, but Hurburgh will remain online as needed to answer additional questions. Participants will need to turn on their computer audio to hear the session.

This has been an extremely difficult year for grain storage. Corn was harvested wet and not all was dried because of dryer capacity shortages. The cold growing season decreased test weights, which naturally reduce storage life.

The 2009 crop has about half the storage life of normal corn, which will make delivering good quality corn in the summer months a real challenge. Penalties for spoiled grain are increasing and the primary user of Iowa corn, ethanol, cannot absorb large amounts of damaged corn.

The steps that should be taken now to prevent or at least reduce corn storage losses will be covered in the webinar.


Charles Hurburgh is a professor of Agricultural and Biosystems . He can be contacted at (515) 294-8629 or by email at

Glyphosate and Manganese Interactions in Roundup Ready Soybean

Bob Hartzler, Department of Agronomy

Shortly after the introduction of Roundup Ready soybean, questions arose whether these varieties and/or glyphosate applications to them alter manganese relations compared to conventional soybean varieties. It is well documented that glyphosate forms complexes with manganese and other metal cations. These complexes reduce glyphosate activity when the antagonistic cations are present in water used as a carrier. 

Research investigating interactions between Roundup Ready varieties, glyphosate and manganese has produced conflicting results. It is important to note that most interactions between Roundup Ready soybean and manganese have been observed in areas with soils known to be deficient in manganese. There have not been reports of manganese deficiency in Iowa. 

Although there has been research indicating Roundup Ready soybean may respond differently to manganese than conventional varieties, the majority of research does not support this observation. The best recommendation remains to manage Roundup Ready soybean similar to conventional varieties in terms of fertility management. For more details about the research investigating manganese relations of Roundup Ready varieties, refer to the complete Glyphosate-Manganese Interactions in Roundup Ready Soybean article, on the ISU Extension weed science Web page.


Bob Hartzler is a professor of agronomy with extension, teaching and research responsibilities.

Iowa Water Conference March 8-9

By Brent Pringnitz, Agribusiness Education Program

"Pulling it all together: Policy, programs and practices” is the theme for this year’s Iowa Water Conference hosted by the Iowa Water Center. The conference will feature the Iowa Stormwater Conference, the Agriculture and Environment Conference and the Source Water Protection Conference. This partnership effort strives to advance Iowa urban and agricultural water issues through sustainable watershed management. 

The Iowa Water Conference will be held March 8 and 9 in the Scheman Building at the Iowa State Center in Ames. Registration opens at 12:30 p.m. and workshops begin at 1 pm. A plenary session follows at 5 p.m., with an evening reception at 6:30 p.m. Sessions resume on March 9 at 8 a.m. and continue until 4:15 p.m.

An exciting program has been developed that features nationally recognized experts such as Ephraim King, U.S. Environmental Protection Agency Office of Water, who will outline the findings and recommendations of the Nutrient Innovations Task Force. Others, including Roger Bannerman, Wisconsin Department of Natural Resources, and Deanna Osmond, North Carolina State University, will discuss what has been done in urban and agricultural watersheds.

The new Iowa Learning Farm video, “Troubled Waters,” will premiere at 4:30 p.m. on Monday, March 8. This film explores rivers and the human relationship with them. When presented with the broad array of information the conference provides, audience participants will be more equipped to address the challenges of pulling policy, programs and practices all together. 

A conference exhibit area will host educational and informational outreach displays that highlight innovative research and programs in conservation, nutrient management, and water quality. Vendors that offer services and products for erosion and sediment control, and storm water management also will have displays in the exhibit area. Organizations or individuals interested in exhibit space, sponsorship or an outreach display should visit for more information and a vendor registration form.

The conference registration fee is $150. Registrations will be accepted at the door. The fee includes lunch, breaks, evening reception and conference t-shirt. Visit for additional information about the conference, registration materials and online registration. For more information, contact the Agribusiness Education Program at (515) 294-6429 or email

This conference is hosted by the Iowa Water Center, in cooperation with Iowa State University Extension, Division of Soil Conservation-Iowa Department of Agriculture and Land Stewardship, Iowa Association of Municipal Utilities, Iowa Storm Water Education Program, Iowa Department of Natural Resources, Iowa Learning Farm program, and the USDA Natural Resources Conservation Service.



Brent Pringnitz is the coordinator of the Iowa State University Extension Agribusiness Education Program. He can be reached at 515/294-9487 or by email at

Bean Leaf Beetle Predictions for 2010

By Erin Hodgson and Nick Schmidt, Department of Entomology

Bean leaf beetles have adapted to Iowa's winters by protecting themselves in leaf litter, but they are still susceptible to cold temperatures. Harsh winters can cause significant mortality. In general, bean leaf beetle adults will die if temperatures fall below -10C. An overwintering model was developed by Lam and Pedigo from Iowa State University in 2000, and is helpful for predicting winter mortality based on accumulating subfreezing temperatures. Figure 1 is a map of predicted mortality in Iowa from the 2009-2010 winter. In general, Iowa experienced very low temperatures, with predicted mortality ranging from 82-99 percent. These numbers are similar to the 2008-2009 winter
predicted overwintering morality of blb

Figure 1. Predicted overwintering mortality of bean leaf beetle based on accumulating subfreezing temperatures from October 2009 – February 2010.

As with all insects, growth and development is highly regulated by temperature. In other words, warmer temperatures will shorten the time it takes to become adults. The overwintering adults become active in late April or May, and begin looking for food. Often soybean isn’t emerged at this time, so the adults may be feeding on alfalfa or other wild legumes. As soybean emerges, the adults will move into fields. The first generation becomes active in July and the second generation emerges in late August or early September. Usually the second generation is much more abundant and has the potential to cause economic damage.

Overwintering adults are strongly attracted to soybean and will move into newly emerging fields. Bean leaf beetle is easily disturbed and will drop from plants and seek shelter in soil cracks or under debris. Sampling early in the season requires you to be sneaky to estimate actual densities. Although overwintering beetles rarely cause economic damage, their presence may be an indicator of building first and second generations later in the season.


Erin Hodgson is an assistant professor of entomology with extension and research responsibilities. Nick Schmidt is a graduate student in the Department of Entomology.

This article was published originally on 3/1/2010 The information contained within the article may or may not be up to date depending on when you are accessing the information.

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