Harvest has officially started in Iowa, but it has been slow as crop development remains behind normal and the rain last week kept farmers out of the field. The lack of frost to date has allowed corn and soybeans to continue to develop and most will soon be mature enough to be safe from freezing temperatures.

The weekly USDA weather and crop conditions survey results released September 28 shows the moisture content of Iowa corn is averaging 32%, 4% higher than the 5-year average. The corn crop remains about 5 days behind average in maturity, but no frost has appeared. About 24% of Iowa's soybean crop has yet to drop its leaves, about 8% behind the 5-year average.

About 2% of the Iowa corn crop and 6% of the bean crop was harvested before rain this past weekend slowed combining, according to the weekly report issued by the Iowa office of USDA's National Ag Statistics Service in Des Moines.

Rain fall slows start of Iowa harvest

Iowa farmers were starting to harvest corn and beans when rain and cooler temperatures moved into the state, delaying harvest. Corn and soybean crop progress continues behind the 5-year average as skies remained cloudy for the majority of the week, says Harry Hillaker, state climatologist for the Iowa Department of Agriculture.

Although cool, Iowa did not receive any reports of frost as of September 28. The rainfall was beneficial to cattle producers as pasture and rangeland needed moisture for cool season grass development.

There were 4.3 days suitable for fieldwork during the week, compared to the 5-year average of 5.1 days. Topsoil moisture rated 3% very short, 20% short, 72% adequate and 5% surplus across Iowa. Subsoil moisture rated 4% very short, 17% short, 75% adequate and 4% surplus.

Half of corn crop is now safe from frost

As of September 28, corn reported at or beyond the dent stage reached 95%, which is 3% ahead of last year, but 5 days behind the 5-year average. Corn reported mature or safe from frost reached 47%, which is 5% ahead of last year, but 9 days behind the 5-year average. Corn harvested for grain has begun with 2% of the state's crop reported harvested, equal to last year, but 4% behind the 5-year average.

Moisture content of all field corn is estimated at 32%, which is 4% higher than the 5-year average. Corn lodging is rated 75% none, 20% light, 4% moderate and 1% heavy. Ear droppage is rated 85% none, 12% light, 2% moderate and 1% heavy. Corn condition is rated 3% very poor, 6% poor, 16% fair, 52% good and 23% excellent.

About 6% of Iowa's soybeans are harvested

Soybean leaves turning color reached 95%, 4% ahead of last year, but 2% behind the 5-year average. Soybeans dropping leaves reached 76%, 10% ahead of last year, but 8% behind the 5-year average. Soybeans harvested reached 6%--that's 1% behind last year and 14% behind the 5-year average.

Soybean lodging is 80% none, 16% light, 3% moderate and 1% heavy. Soybean shattering is rated 86% none, 11% light and 3% moderate. Soybean condition is rated 2% very poor, 5% poor, 19% fair, 55% percent good and 19% excellent.

Alfalfa third cutting has reached 93% complete, 4% ahead of last year, but 4% behind the 5-year average.

Pasture and range condition is rated 2% very poor, 12% poor, 29 % fair, 47% good and 10% excellent. Cattle on feed recorded average gains as temperatures remained low. Stress levels did increase for cattle on feed as dry lots became muddy due to rain showers last week.

Good start for harvest in northwest Iowa

"The soybean harvest has started in northwest Iowa, and early yield reports are mixed to a little lower than hoped," says Joel DeJong, Iowa State University Extension field agronomist at Le Mars. Most early bean reports he's heard are below what was harvested last year – by about 5 bushels or so per acre.

"I don't think many farmers are surprised by lower yields," he adds. "Because the cooler temperatures this summer and very rapid dry down in September seemed to lead to lower node numbers and small bean sizes."

However, DeJong says there will be neighborhoods in northwest Iowa that will match the bean yields produced last year or possibly even surpass them. "We are just getting started with the 2009 bean harvest, so I think we'll likely have a better handle on this next week. Stems are still green in many cases, and the combines are growling. That seems more typical than unusual anymore."

Check cornfields now for signs of stalk rot

Kyle Jensen, ISU Extension field agronomist in southwest Iowa, says corn stalks look to be in good condition where he is pulling end of season nitrate tests. But in northwest Iowa, DeJong has seen quite a few cornfields with some stalk rot beginning to show up recently.

The most common method to scout for stalk rots is to use the Push Test or Pinch Test, he says. Walk through a field and randomly select a minimum of 100 plants representing a large portion of the field. To test for stalk rot, push the plant tops sideways, about 30-degrees from vertical. If plants fail to snap back to vertical position, that means the stalk has been compromised by stalk rot.

Also, pinch or squeeze the plants at one of the lowest internodes above the brace roots (pinching the same internode on each plant). If the stalks crush easily by hand, they have been weakened by stalk rot. "If more than 10% of the corn plants exhibit stalk rot symptoms, you should harvest that field first to reduce the potential for plant lodging and yield loss," says DeJong. "Under severe stalk rot conditions, it may be more economical to harvest early at higher moisture and dry grain than to experience severe harvest losses."