Late-season Corn Development and Frost Probabilities

Cool August temperatures across Iowa slow growing degree day (GDD) accumulations. In addition, Iowa’s late corn planting dates this year obviously impacted the crop as well. These two factors affect corn yield potential

Root-lodged corn at or before silking

Several areas of Iowa last week experienced strong winds along with thunderstorms. Fortunately, these storms provided some much-needed moisture for kernel set on corn, but the winds in some places were strong enough to root lodge corn. Corn affected ranged from just silked (R1), the blister stage (R2), to some in the milk stage (R3). In areas with corn not yet tasseled, greensnap occurred. I\u27ll discuss greensnap another time. For this article, I\u27ll discuss the following: Why did some plants root lodge and others didn\u27t? How will root lodging affect yield? And what can we learn that will reduce root lodging in the future

Corn Crop Development and Conditions at the End of July 2012

To no one’s surprise, Iowa corn conditions declined throughout the month of July. Dry hot weather hammered the crop to the point where some crops were written off as unproductive several weeks ago and others are seemingly hanging by a thread. Some producers are salvaging what remains as silage. Nevertheless, some Iowa producers are quite satisfied with their crop’s potential. They are among the fortunate few perhaps with a bit better soils and more rain at critical periods. Undoubtedly, this group may also have an edge on management practices: excellent hybrid selection, less soil compaction, timely planting dates, better seed placement, uniform seedling emergence, optimum plant populations, top-notch weed control, wise insect and disease management, etc. This will be the year where the management differences among fields and producers - and their skills - will come to light

Corn Emergence in 2009

Corn spikes through fertile soil of early-planted fields in most parts of Iowa as I write. According to the May 4, 2009 USDA-NASS estimates, 2 percent of Iowa’s corn is emerged compared to none last year and the five year average of 7 percent

Corn and Dry Soils at Planting, Looking Ahead to 2012—Part I: Yield prediction with dry conditions at planting

Dry conditions persist in many parts of Iowa. As of Jan. 30, modeled volumetric root-zone soil water in the northwestern half of the state was one-third or less (see Mesonet map). Elwynn Taylor, Iowa State University Extension and Outreach climatologist, indicates there is some probability that these dry conditions will persist

Try Side-by-Side Trials to Check Fungicide Impact on Corn Yield

The decision of whether we should apply a fungicide to corn in mid-season will depend on two sets of factors. First are the main economic drivers: the value of the corn produced, and the costs of the fungicide and its application. The second factor that balances these is the degree to which yield is actually affected

What is Needed to Maximize the 2008 Corn Crop

Iowa’s corn has experienced an unforgiving growing season. With the last breaths of summer in the air many wonder what it will take to maximize yields from this date forward. According to the recent USDA report, Iowa’s corn is about two weeks behind the five year average. Eleven percent is ready for a frost, 71 percent is in the dent stage. At beginning dent the crop normally needs about 3 weeks to mature. The bottom line - regardless of location in Iowa, the corn crop needs a normal or later than normal frost date to maximize yields

Influence of Soil Temperature on Corn Germination and Growth

We experienced June-like temperatures in March. Trees budded, spring flowers bloomed and fertilizer rigs crisscrossed fields. Soil temperatures matched what we normally experience in late April and early May, jumping well ahead of previous records. Because of the unparalleled warm March weather, many wonder about planting corn. Perhaps some did plant. This year’s warm spring temperatures encouraged early development of flowering trees and shrubs, as well as lawns, pastures and early weed-flushes in many fields - But wait until at least the April 11 crop insurance date to plant corn! Data from other scientists and Iowa planting date studies – suggests to plant corn after mid-April when soil temperatures are near 50 degrees Fahrenheit to maximize yield

Best Corn Planting Dates for Iowa

Optimum Iowa corn planting dates range from mid-April to the end of April in North Central and Northeast Iowa and to the first or second week in May in other parts of Iowa (see Table). If we consider the differences between early-planting and late planting, yields are reduced less early in the planting season than late. That means that planting early during the optimum window is generally a better practice than planting a few days after the optimum window. Yields drop off dramatically in mid-May across Iowa. If possible, plant corn prior to May 15 to avoid this slippery slope of rapidly reducing yield potential

Stress, Anthesis—Silk Interval and Corn Yield Potential

Forecast daily high temperatures every day this week hover just below 100 degrees. Across Iowa corn ranges from the 10th leaf stage (V10) to tasseling and silking (VT and R1). As of July 1st, the USDA reports that 16 percent of Iowa’s corn was silking; that\u27s nearly 2 weeks ahead of normal. Unfortunately, dry surface and subsoil moisture conditions prevail (see June 26, 2012, Drought Monitor). In the USDA report linked above, 73 percent of Iowa\u27s subsoil moisture was reported as either short or very short compared to 2 percent last year. Crop water use ranged between 0.2 and 0.4 inches per day in central Iowa the last few days (see Soil Moisture Conditions and Crop Water Use, ICM News, for more information on this). With the majority of Iowa’s corn pollinating in the next week to 10 days, this combination of events does not lead to optimism among Iowa’s corn agronomists