Using historical data from your growing area, your custom CropFax report will provide you with charts on:

• Growing Degree Days
• Last Spring and First Fall Freeze Dates
• Precipitation Probability and Soil Temperature

Growing Degree Units
Growing Degree Units (GDU) shown on the prior graph measure how much time and heat are required for a hybrid to mature.  Your supplier can tell you how many GDUs are required for their hybrids.  The relationship between GDUs and RM (relative maturity) is not fixed, but each day of RM is about 25 GDUs.

Suppose you’re planting late this spring.  CropFax agri-climate data such as GDU, soil temperature and probability for freeze dates and precipitation can help you determine how much of a risk you’re taking with various hybrids.  Iowa State Extension says “growing diverse hybrids is imperative!”  They recommend spreading your risk by planting varieties with different genetic traits, maturities and disease susceptibilities.

Besides focusing on yield and maturity, your CropFax report will help you see the lodging characteristics of top hybrids in your area.  Greg Roth of Penn State says, “Standability is an especially important hybrid characteristic…especially where corn harvest often continues late into the fall.”

Another key factor to consider is harvest moisture.  Mike Stanton of Michigan Farm News says “corn hybrid maturity can have a significant effect on harvest moisture, drying cost, and test weight…a good rule of thumb is that a one point increase in grain moisture will require approximately 2 bushels per acre more yield to break even.”  Your CropFax report will give you relevant genetic performance for dry down as well as necessary climate data (freeze dates) so that you can select the right variety for your growing area.

Last Spring and First Fall Freeze Dates
When will be the last freeze this spring, or the first freeze next Fall?  We don’t know –but based on 30 years of county data you will receive probabilities on when it is likely to happen.

What is the maximum growing season that can reasonably be expected in your area?  These long-term averages for frost dates can help you estimate.  Sometimes a few warm springs or late planting seasons can distort our perceptions.  While nothing is guaranteed, long term averages are better than short term memories. 

Agronomist Peter Thomison at Ohio State University says your corn should reach the black layer stage 1-2 weeks before the average date for the first killing frost.  These charts plus the GDU chart on the previous page will help you decide whether to use a short or long maturing hybrid.  Also consider field drydown vs. artificial drying costs when making this decision.

Precipitation Probability and Soil Temperature
All growers know the importance of precipitation –the right amount at the right time.  We can’t prevent you from getting rained out, but your CropFax Report graphs will show the probability of it happening at any time of the year. Also, if you live in an area with high amounts of summer rain, you might consider planting several hybrids with different values of GDUs to mid-silk (or days to silk).  This will lessen this risk of heavy rains damaging your entire crop during pollination.

Spring soil temperature is critical for proper emergence,  your CropFax report will show that it can vary significantly from year to year.