Crop Progress Report, Growing Degree Days and more

Iowa’s crop season got off to a slow start. From April 15^th to May 15^th, pretty much all of Iowa was below normal in accumulated growing degree days with northwest Iowa lagging the furthest behind normal (Figure 1). Ocheyedan (CFE) was 46 GDDs behind normal. Chariton was 18 GDDs below normal.  

Corn planting in Iowa is normally 50% completed by about May 4^th.  This year, only 14% of the Iowa corn crop was planted by May 7^th (Figure 2).  Wet, cold soils kept the planters out of the fields.  Over the next two weeks, corn planters rolled across Iowa.  By May 21^st, USDA estimated that 86% of Iowa corn had been planted and by May 28^th, Iowa was actually slightly ahead of normal planting progress with 94% of the corn planting accomplished. 

Soybean planting in Iowa was also slow to start with only 7% of the seed in the ground by May 7^th but 69% done by May 21^st and 85% completed by May 28^th, a full 10 percentage points ahead of the 5-year average (Figure 2). 

Figure 3. Iowa Growing Degree Days, May 15th - June 27^th 

Since May 15^th, the warmer weather has prevailed in Iowa and nearly all reporting stations are now showing more GDDs than average for that period (Figure 3). Chariton accumulated 847 GDDs during the period of May 15 – June 27^th, 75 GDDs more than normal for that period. Ocheyedan (CFE on the map) accumulated 706 GDDs from May 15^th – June 27^th, 23 GDDs more than normal. 

Figure 4. Iowa Cumulative Growing Degree Days, April 15th - June 27th 

The southern and southeastern parts of the state have “caught up” on GDDs and are now significantly ahead of normal (Figure 4). Chariton now has accumulated 1,115 GDDs since May 15^th and is 57 GDDs ahead of normal. Ocheyedan (CFE on the map) has accumulated 891 GDDs and is still behind by 23 GDDs since May 15^th. 

Figure 5. Iowa Crop Condition (Pct Good to Excellent) 

Despite the delays in the start of planting, the Iowa corn and soybean crops are off to an overall great start.  In the most recent weekly crop condition report, 80% of the Iowa corn was rated “Good to Excellent” and 80% of Iowa’s soybeans were rated “Good to Excellent.” This compares to a 5-year average rating for corn of 73% and a 5-year average for soybeans of 72% (Figure 5). 

Economic analysis provided by David Miller, Consulting Chief Economist, Decision Innovation Solutions on behalf of Iowa Farm Bureau.