Integrated Crop Management News

Links to these articles are strongly encouraged. Articles may be republished without further permission if published as written and if credit is given to the author, Integrated Crop Management News, and Iowa State University Extension and Outreach. If articles are used in any other manner, permission from the author is required.

Surface Waters: Ammonium is Not Ammonia – Part 1

April 21, 2008

By John Sawyer, Department of Agronomy

A recent article in The Des Moines Register newspaper has caused considerable controversy regarding nitrogen in Iowa streams and rivers. The article (High ammonia levels threaten D.M.’s water, April 6, 2008) featured information about “ammonia” levels in certain Iowa surface water systems during the recent winter time period.

Iowa 2008 Prediction for Stewart’s Disease of Corn

April 17, 2008
Map showing the Stevens-Boewe Index

By Forrest W. Nutter, Jr., Department of Plant Pathology, Lu Liu, Sustainable Agriculture Program, Rich Pope, Department of Entomology, and Marlin E. Rice, Department of Entomology

Following an Iowa winter of ice, snow and cold temperatures, the predicted risk for Stewart’s disease of corn in 2008 is negligible throughout most of Iowa, with only the southeastern-most counties having a low risk.

Calculating Degree Days

April 17, 2008

By Rich Pope, Department of Entomology

Warm-blooded animals including humans generate their own internal heat and have regulatory systems to hold maintain body temperature in an operational range. These systems provide insulation from fluctuations of temperature in the environment and allow growth and development based on the passage of time in minutes, hours, weeks, months and years.

Too Early to Worry about Planting Corn!

April 16, 2008
Graph of Iowa corn planting progress ending April 21

By  Roger Elmore and Lori Abendroth, Department of Agronomy

Rain is forecast again for most of Iowa later this week. Little if any spring work has occurred because of cold weather and already saturated soils. More rain right now is not welcome for most of us corn growers!

Starting Clean in No-till

March 26, 2008

Bob Hartzler, Department of Agronomy

As more Iowa fields develop a history of no-till production, infestations of winter annual weeds are on the increase. The first step in managing winter annuals is proper identification of the species infesting the field. Many agronomists are relatively weak at identifying these weeds. A regional extension publication - Early spring weeds on no-till crop production  (NCR 614) - can assist in this process.