The sunny forecast this week is expected to help dry out the saturated and flooded field conditions so farmers get back in the field to plant corn and soybeans. The USDA crop progress report issued on May 7 says that 53 percent of the planned Iowa corn acreage is now planted and 4 percent of the soybean crop is planted. For those farmers still waiting anxiously to plant, two Iowa State University (ISU) Extension agronomists are advising producers not to go switching hybrids and varieties of corn and soybeans just yet.
"There is no need to think about changing hybrids until the end of the month. Hybrids easily adjust to these later planting dates," said Roger Elmore, professor and Iowa State University Extension corn agronomist. "Yield potential for corn has not declined and won't for another week or so. There is no need to get too concerned about late planting yet." Elmore has more information on this topic on his Web page at www.agronext.iastate.edu/corn/production/management/planting/delayed.html.
"Even though it is wet out there in most areas, we are still in the first part of May and have several weeks left for planting soybeans," says Palle Pedersen, assistant professor and Iowa State University Extension soybean agronomist. "The same recommendations exist for the growers whether it is the last week of April or the last week of May." Pedersen encourages farmers not to switch soybean varieties to a shorter maturity group yet, since full season soybean varieties can be used through the first week of June without problems.
More information on soybean production and recommendations for Iowa can be found at his Web page www.soybeanmanagement.info.
The saturated and flooded crop plan may have an impact on nitrogen (N) for this season's corn crop according to John Sawyer, associate professor and Iowa State University Extension soil fertility expert. Sawyer says having the wet conditions occur in the early spring is helpful as soils are cooler, so less fertilizer is converted to nitrate, and losses by denitrification in flooded fields are slower.
"Losses are occurring. The best course of action now is to wait, get the crops planted, and then use tools like loss estimation, soil nitrate testing, and corn plant N stress monitoring to check on the N status and determine if additional N is needed. Rushing out to apply more N could put that N at risk if we get more wet conditions. For now, follow your intended planting plan as best you can," he said.Sawyer advises crop advisers and farmers dealing with nitrogen issues on flooded cropland to check past newsletter articles posted on the Iowa State University Extension soil fertility Web page. New articles dealing with the wet conditions will be posted there also.
The Iowa State University Integrated Crop Management newsletter is another source for current crop recommendations from Iowa State University Extension experts. The newsletter is issued weekly during the crop season and can be viewed at www.ipm.iastate.edu/ipm/icm.
Jean McGuire is a communications specialist with responsibilities for agriculture and natural resources extension.
This article originally appeared on pages 143-144 of the IC-498 (9) -- May 7, 2007 issue.