Iowa's 2010 corn and soybean crops have continued to progress at a faster than normal pace toward maturity. Chopping corn for silage and harvesting of seed corn are already in full swing across the state, and some harvesting of corn for grain has started in the early planted fields.
While corn is rapidly turning color and maturing, soybeans are mostly still green across much of Iowa—except for areas of bean fields that have been affected by the disease Sudden Death Syndrome. However, soybean progress statewide is still ahead of last year. Hay production also progressed last week with farmers continuing their third cutting, with some moving onto a fourth cutting. Pastures remain adequate for grazing, and they should have enough moisture to provide growth for the remainder of the grazing season.
That's the summary of the weekly weather and crop conditions report released September 7 by the Iowa office of USDA's National Ag Statistics Service. The weekly report is based on statewide surveys made by official crop reporters.
Iowa's corn and soybean crops still rate 69% good to excellent
Nearly all corn acres in Iowa have now entered dough stage, 90% of the crop has started to dent and 34% has reached maturity; all three of these categories are at least 9 days ahead of last year at this time, and ahead of the 5-year average. Corn has begun to be harvested in a few areas of Iowa. The condition of the 2010 Iowa corn crop has decreased slightly during the past week. It is now rated 3% very poor, 8% poor, 20% fair, 46% good and 23% excellent.
The September 7 weekly report shows 45% of the state's soybean acres have turned color, which is ahead of last year's 26% and the 5-year average of 39%. Leaves have begun to drop for 9% of the soybean acres, 3 days ahead of last year, but 1 day behind the 5-year average. Soybean condition decreased slightly this past week to 3% very poor, 7% poor, 21% fair, 47% good and 22% excellent. Alfalfa third cutting increased 12 percentage points to 81% complete, ahead of the 70% completed last year at this time, and the 5-year average of 78%. The condition of all hay in Iowa is currently rated 4% very poor, 10% poor, 28% fair, 45% good and 13% excellent.
Pasture and range condition is now rated 2% very poor, 6% poor, 25% fair, 49% good and 18% excellent. There have been no reports of any widespread livestock concerns; however isolated cases of pink-eye in cattle and high populations of insects have been reported.
Why has this year's corn crop raced toward maturity?
With the hot weather this summer, growing degree day accumulation has been running ahead of normal since early July, says Elwynn Taylor, Iowa State University Extension climatologist. That's been a negative factor on yields.
"With growing degree days running ahead of normal since the first of July, that has advanced the crop growth and shortened the time available for the crop to reach maturity," says Taylor. "A lot of farmers tell me this year's corn crop is racing toward maturity--it's going faster than they've ever seen it mature in a year when we didn't have a drought. Well, they are exactly right. That's because crop maturity this summer was advanced by the warmer than normal nights we had. The crop matures faster in those types of growing conditions. What it means is there are fewer days for the corn kernels to gain weight, and that does cost you some yield potential. You end up getting less yield per acre."
USDA will release its September Crop Production Report on Friday September 10, which will update the official yield estimates that were made in August.
What will the September 10 USDA crop size estimate show?
USDA in its last crop production report (the August Crop Report) estimated that the 2010 U.S. corn crop will yield 165 bushels per acre—that's a nationwide estimate. Private forecasters have in recent days released their guesses, which reduce that August USDA number by 2 and some say 3 bushels per acre.
"That comes right to the number I've been estimating," says Taylor. "That is, I've reduced the previous USDA estimate by 3 bushels per acre because the degree day accumulation has gone faster than usual, shortening the time this year's corn crop has had to pack weight into the kernels. I think 162 bushels per acre is a realistic number for the 2010 U.S. average yield. Cutting three bushels off from the previous estimate is realistic. Maybe when the final crop numbers come in at the end of harvest, it could be a bigger yield. But we're not to the end of the season yet, so we'll have to wait and see."
How fortunate are we that the LaNina weather pattern, which is firmly in place today, arrived in late June and early July rather than early in June?
"We don't know if it was fortunate or not," answers Taylor. "But we do know that when a LaNina is present, the opportunity is really there for the weather to get a lot hotter and a lot drier and we are glad that such an opportunity really didn't show up this summer--because the corn roots weren't deep this year on the crop. This year's crop wouldn't have been able to take the hot, dry weather."
Iowa had a lot of hot weather but it was rainy and humid, not dry
Iowa had a lot of rain to go along with the hot weather this summer. "When it's hot, the crop needs a lot more water," says Taylor. "But with the rain there, the crop had the moisture it needed on those hot days this year. So the leaves weren't curling up very much. We know the corn plant is suffering for water when the leaves curl. Likewise, we know soybeans are suffering for water when the leaflets fold up together, as if they are in a prayer for rain."
"When the crop is curling its leaves, the plant is really not gaining dry weight," he adds. "So that's a setback. But the crops didn't have to put up with that this year because of the large amount of rain we received. I didn't hear very many reports of curled corn leaves this summer."
When a LaNina shows up, it leads to weather extremes. Certainly we've had both extremes in Iowa in 2010--extremely warm or hot weather and also a lot of rain this year. Is that a La Nina impact? "It can be, especially when you realize we've had some chilly days too. You wore a sweatshirt in early September already when you went out in the morning," notes Taylor.
If we have early frost this fall, it likely wouldn't hurt crops much
The cool weather this past week or so makes it seem almost like fall already is here, especially in the mornings. Some people are talking about the possibility of an early frost. "If we have an early frost this year, especially with corn and beans having hurried to maturity, the frost would be almost a non-event," says Taylor.
"With the rapid maturity of this year's crop, an earlier than normal frost wouldn't be bad. No real yield loss would be expected."
What's kind of a winter is Taylor looking for? "The thing we want to watch for this coming winter is a condition different from the past three years," says Taylor. "That is, we won't go into winter sopping wet in Iowa which means we won't have so much risk of having too much moisture at planting time in the coming year. So that would be welcome and I think Iowa farmers can look forward to it."
So it looks like maybe we'll have good weather for planting going into spring 2011, he adds. Iowa started out with good planting weather this year, then the monsoon started in May and stretched through June and July.