Rain delays and changes in planting decisions are forcing a later than ideal start for Mississippi’s soybeans.

As planting window dates have been closing for other crops, growers are switching some fields to soybeans before time runs out for them as well.

Trey Koger, soybean specialist with the Mississippi State University Extension Service, said the crop’s ideal planting window closed around the first of May, but fields planted now still can succeed.

Other row crops such as cotton, corn and rice aren’t as flexible when it comes to planting date and optimal yields, so when rain kept fields from being planted in these crops, many farmers turned to late-planted soybeans. Soybeans also are not as expensive to grow as other crops.

“Long-term data shows that the later we get, the more our yields start falling off,” Koger said. “Last year was an exception, and we ended up having a phenomenal crop on our late-planted acreage.”

About 75 percent of the state’s soybean crop was planted by the first week of June. Historically, only about 2 percent to 5 percent of the crop remains at this late date. Rains in early May kept farmers out of the fields for most of the first half of the month. When it dried out, planting resumed in earnest.

“They’re planting hard right now and trying to finish before the next rain,” Koger said.

Modern farm machinery makes it possible for farmers to plant a lot of acres quickly. Producers are working now to beat the clock.

“The later you plant, the more dependent you are on Mother Nature to really make the crop,” Koger said. “If weather cooperates and we get some summer rains, we can make a good crop. Otherwise, farmers with irrigation will have to water more, and that costs more.”

About 65 percent of the state’s soybean acreage is irrigated.

Insects also can pose a problem in late-planted soybeans.

“The later we plant and the later in the year the crop is out there, the more insects we encounter,” Koger said. “You can manage those insects, but you usually have to spend a lot more than if we had April-planted beans.”

Mississippi farmers are planting more than 2.5 million acres of soybeans in 2009, the highest acreage since the early 1990s, Koger said. The increased acreage can be attributed to good soybean prices and input costs that are lower than those for the other major row crops.

John Coccaro, Warren County Extension director, said about half the soybean acres in his county are flooded, while the crop on the high and dry acres is doing well.

“We have flooding from the Mississippi River, the Yazoo River and backwater,” Coccaro said. “The U.S. Army Corps of Engineers, Vicksburg District, said a total of 404,000 acres of agricultural and forest acres are flooded in Warren, Issaquena and Sharkey counties.”

The backwater flooding occurs in the south Delta north of the Yazoo River where it curves to meet the Mississippi River. A flood gate closes when the river rises to prevent river water from flooding nearby land. This year, excessive rains could not drain out of the area because the closed gate that was holding back Mississippi River flooding held in the rainwater.

“When the U.S. Army Corps of Engineers opens the gate, it will probably take two weeks without rain to drain the area and another week for the soil to dry out enough to support a tractor and planter,” Coccaro said.

“Farmers are faced with the dilemma of deciding whether or not to replant a crop the first week of July. Should you borrow again and try to risk a crop that has a high chance of not making?”

Information from the U.S. Army Corps of Engineers on Mississippi River flooding and forecasts can be found online at http://www.mvk.usace.army.mil.