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10/18/2010 - 10/24/2010

Integrated Crop Management Conference set for Dec. 1-2

by Brent Pringnitz, Department of Agronomy

The Iowa State University Integrated Crop Management Conference will be held Dec. 1 – 2 on the ISU campus. Registration begins at 7:30 a.m. on Wednesday, Dec. 1 in the Scheman Building and the program concludes at 4 p.m. Dec. 2.

Conference attendees can choose from 36 workshops that offer the latest information on crop production and protection technology in Iowa and surrounding states. Workshops are offered by ISU faculty and staff and invited speakers from around the Midwest. The conference is hosted by ISU Extension, the College of Agriculture and Life Sciences.

A popular feature of the conference is the variety of guest speakers on the program. Iowa State specialists invite colleagues in their field to share their research activities with conference attendees. This provides an opportunity to hear expertise and opinions from across the region and country at one location.

Invited speakers this year include:
• Bill Northey, Secretary of Agriculture, State of Iowa, speaking on the Iowa statewide nutrient reduction initiative
• Peter Thomison, Ohio State University, on selecting corn hybrids for performance and profit
• Richard Fawcett, Fawcett Consulting, presenting on fifty years of atrazine and its benefits, impacts and current status
• Paul Fixen, International Plant Nutrition Institute, discussing the 4R nutrient stewardship program
• Robert Mullen, Ohio State University, speaking about nitrogen additives, what they are and do they work
• Dorivar Ruiz Diaz, Kansas State University, on managing poultry manure nitrogen for optimum corn yields
• Paul Jasa, University of Nebraska, speaking on no-tillage and water issues

In recent years the conference has filled to capacity with nearly 1,000 producers and agribusiness people in attendance. The conference is fortunate to have a loyal following of people that attend each year. While filling to capacity is a good problem to have, we hate to turn people away and encourage people to register early. Attendees can obtain Certified Crop Adviser credits as well as recertification for Commercial Pesticide Applicators in categories 1A, 1B, 1C, 4 and 10.

Register online or find more information at the conference website. Registration is $185. After Nov.19, registration increases to $235. Enrollment is limited and no registrations will be accepted at the door.


Brent Pringnitz is the conference coordinator and is with ISU’s Corn and Soybean Initiative.

Warm Fall Temperatures, SCN and Winter Annual Weeds

By Greg Tylka, Department of Plant Pathology

We have had a wonderfully sunny, warm, dry fall so far this year.  How could anyone complain about the weather?  Leave it to a nematologist.

Yesterday's ICM News article reminded growers and agronomists to delay application of anhydrous ammonia fertilizer until soil temperatures drop below 50F. It turns out that 50F is also an important temperature to consider for soybean cyst nematode (SCN).

The winter annual weeds chickweed, henbit and purple deadnettle are good hosts for the SCN. But SCN juveniles do not develop in roots when temperatures are below 50F.  So cool fall and spring temperatures usually keep SCN reproduction on these winter annual weeds in check. Such may not be the case this fall.

The chances of having soil temperatures in Ames, Iowa below 50F on Oct. 19 are estimated to be 75 percent (see ISU 4 inch soil temperature probabilities). But today - Oct. 20, most of Iowa still has soil temperatures in the mid 50sF (see figure). 

Growers and agronomists managing SCN-infested fields with significant populations of winter annual weeds should be aware that considerable SCN reproduction could be occurring on these alternative hosts this year. See the ISU Soybean Cyst Nematode web page more information about the biology, scouting and management of SCN.

Soil temperatures on October 20, 2010, at a 4 inch depth (source: Elwynn Taylor, ISU 4 inch soil temperature map).



Greg Tylka is a professor of plant pathology with extension and research responsibilities in management of plant-parasitic nematodes.

Wait Until Soil Temps Drop Before Applying Anhydrous Ammonia

By John Sawyer, Department of Agronomy; Barb Stewart, USDA-NRCS; and Bill Ehm, Iowa Dept. of Natural Resources

With the early harvest, Iowa’s conservation leaders are encouraging farmers to wait until soil temperatures lower before applying anhydrous ammonia (NH3) this fall. Anhydrous ammonia applied before daily soil temperatures remain below 50 degrees Fahrenheit and continue trending lower can result in the nitrogen loss that can impact crop development and have negative environmental impacts, such as enhanced leaching into groundwater and streams once converted to nitrate.

By waiting for cold soil temperatures, the applied ammonia will have a better chance to be retained in the soil and benefit the crop next spring. Cooler soil temperatures slow biological activity, which slows conversion of ammonium to nitrate, therefore allowing nitrogen to stay in the ammonium (NH4) form longer.

Heavy rains throughout 2010 caused a lot of yellow corn due to nitrogen loss. Stewart says applying anhydrous ammonia prior to soils dropping below 50 degrees could produce similar results. With high anhydrous prices this fall, consider a spring or split spring/sidedress application to make the best use of the nutrients.

Historically, soil temperatures at a 4-inch depth cool below 50 degrees in the northern third of the state during the first week of November. In central and southern Iowa, soil temperatures cool below 50 degrees during the second week and third weeks of November. Producers and fertilizer dealers are encouraged to visit the Nitrogen and Phosphorus Knowledge web page to view daily, previous day, and 3-day history of average soil temperatures in every Iowa county.

ISU Extension research indicates lower yields can result when anhydrous ammonia is applied in the fall versus spring, and crop residue cover can be reduced by the tillage action of NH3 application, increasing the risk of soil erosion.

To save energy and money, NRCS recommends farmers use online energy estimators for tillage and nitrogen. The energy estimator for tillage estimates diesel fuel use and costs in the production of key crops. It compares potential energy savings between conventional tillage and alternative tillage systems. The energy estimator for nitrogen enables farmers to calculate the cost of nitrogen product use. It also evaluates options based on user input.

According to the USDA, nitrogen fertilizer is one of the largest indirect uses of energy in an agricultural operation. Fertilizer accounts for 29 percent of agriculture’s energy use, according to USDA research data. The energy consumption for nitrogen fertilizer manufacture and relation to application rate is outlined in an ISU Extension publication, Energy Consumption in Corn Nitrogen Fertilizer. Proper management of nitrogen fertilizer, including the use of organic sources of nitrogen, such as animal manure and cover crops, can save producers energy and money.

This article was published originally on 10/25/2010 The information contained within the article may or may not be up to date depending on when you are accessing the information.

Links to this material are strongly encouraged. This article may be republished without further permission if it is published as written and includes credit to the author, Integrated Crop Management News and Iowa State University Extension. Prior permission from the author is required if this article is republished in any other manner.