Just as people were gearing up for fireworks this past weekend to celebrate the Fourth of July, rain began to fall on some areas of Iowa. Many farmers were finally able to enter fields to finish herbicide applications. Temperatures were slightly below normal for what turned out to be a good week for Iowa crops and livestock.

The mostly dry weather early in the week and the more comfortable temperatures were good for crop development and provided needed relief for livestock. With everything planted and most weed control finished, hopefully timely rains and few pests will allow the state's 2009 crops to continue development without interruption. That's the summary from the weekly weather and crop condition report, based on surveys as of July 5 and compiled and released July 6 by the Iowa Field Office of USDA's National Ag Statistics Service.

As of July 5, the statewide survey shows Iowa's 2009 corn crop has just begun to tassel with 2% tasseled compared to the 5-year average of 11%.  Corn condition is rated at 27% excellent, 55% good, 14% fair, 3% poor and 1% very poor.

Nearly 25% of state's soybean crop is blooming

The corn stand statewide is rated at 95% of normal with 100% considered normal. The corn stand's tallest height averaged 67 inches with an overall statewide corn height of 52 inches as of July 5.

Most of Iowa's soybean acres have been planted and 97% are emerged. Soybean emergence is slightly ahead of last year but behind the 5-year average. Soybeans blooming in Iowa reached 23%, about 3 days ahead of last year but behind the 5-year average. Soybean condition is rated 21% excellent, 59% good, 16% fair, 3% poor and 1% very poor as of July 5.

The oat crop reached 92% headed, 9% ahead of last year but 3% below the 5-year average. And 32% of the Iowa oat crop is now turning color, 10% ahead of last year but 16% behind the 5-year average. Oat condition is rated 18% excellent, 57% good, 21% fair and 4% poor.

Second-cutting alfalfa hay now 21% complete

The first cutting of alfalfa hay is 94% harvested, behind the 5-year average of 97%. Farmers have begun their second alfalfa cutting and it is now 21% complete, compared to 27% for the 5 year average at this time. All hay condition in Iowa is rated at 12% excellent, 48% good, 28% fair, 9% poor, 3% very poor.

Livestock and pasture condition rates 21% excellent, 51% good, 21% fair, 6% poor and 1% very poor as of July 5. Stress levels on pasture decreased with the temperature decline, while feedlots continue to deal with constantly muddy pens.

"There's a lot of good looking corn in Iowa, especially in the northern part of the state," says Roger Elmore, Iowa State University Extension corn agronomist. "You have to add southwest Iowa in there too—as there's some really good corn in that part of the state. It's tasseling in some places in southwest Iowa. However, the corn in south central and southeast Iowa isn't quite so pretty."

Are we catching up on heat units this summer?

"When it was so hot two weeks ago, Iowa gained some heat units. Last week we lost a little bit of that gain," says Elmore. "So we're still two to four days behind schedule in terms of heat units this summer, but that's not a big deal this time of year. I'm not worried."

What about southeast Iowa? Is there a problem in that part of the state as far as getting caught up? "Over the weekend that area of Iowa got some more rain," notes Elmore. "So in many of the low-lying soils, there's a lot of uneven growth of corn plants in southeast Iowa, especially corn following corn fields in a crop rotation. So, crops aren't as good looking in southeast and south central Iowa."

To have 82% of Iowa's corn crop good to excellent, as the government's July 6 weekly crop condition and weather survey showed, is extremely high. Last year at this time it was only 53%. That's about where Illinois is this year. But relative to the other crop reporting districts in Iowa right now, southeast isn't that good. It's been a tough year for them. They've had a lot of rain the rest of Iowa didn't get.

Are there any problems with Iowa's corn crop?

This week we'll see tassels everywhere in the state. Strong winds have had an effect in some areas of the state. There were some strong thunderstorms this past week in areas of southwest Iowa that caused some root lodging when the corn plants were in the 14^th to 16^th leaf stage of growth. Also, greensnap can happen this time of year—as strong winds can break the corn stalks off during the period just prior to tasseling when the corn plant is growing rapidly.

"Those are a couple of negative things that can happen to corn and you really can't do much to prevent it," notes Elmore.

Hybrid selection may make some difference in terms of corn being better able to keep standing, but in terms of root lodging, when you get a cool, wet growing season like we've had this year, those roots are going to be shallow. Even without rootworm feeding, some of the corn plants can blow down, he says.

Some greensnap has also been reported in the Waterloo area of northeast Iowa this summer. There were high winds in that part of the state a couple weeks ago. "I saw greensnap back in the early 1990s in Nebraska. And every year since then I've seen some greensnap occur somewhere," says Elmore. "The seed companies obviously are doing a lot of research to increase corn hybrid tolerance to greensnap. But still, part of what we're doing is breeding for high corn yields and when you do that it creates a brittleness in the stalks that right before tasseling is very hard to control when you get strong winds."

How can you prevent greensnap of corn?

You can reduce the risk of it occurring by changing the corn row orientation, he says. Rather than planting all of your corn fields in a north-south or east-west direction, you can plant some of the fields one way or the other way and mix the corn crop up a bit. You can plant one field in a north-south direction and another field in an east-west direction. And you can also plant some hybrids that are more tolerant to greensnap. There's been some progress but there remains a long way to go in breeding corn for better greensnap tolerance.

"I don't think I've ever been in a field situation where there was a greensnap event and both the north-south planted fields and the east west rows are lodged or broken over," adds Elmore. "Also, keep in mind that once you lose a corn plant at this stage of growth, you lose that proportion of yield. It's a one-to-one relationship."