Extension News

ISU Extension Offers Information on Handling Flooded Crops and Saturated Soils

8/24/2007

AMES, Iowa -- Several Iowa State University Extension crop production specialists are making recommendations to Iowa crop producers for dealing with the heavy rainfall, hail and flooding that has hit several parts of the state recently.

The following short online presentations are available as part of Iowa Late Summer: Wet Field Conditions page at www.extension.iastate.edu/ag/hottopics.html

Corn Production Considerations
Roger Elmore, ISU professor and ISU Extension agronomist, discusses the agronomic considerations of excess moisture on the maturing corn plant.
 
Soybean Production Considerations
Palle Pedersen, ISU assistant professor and ISU Extension agronomist, discusses the agronomic considerations of excess moisture on the maturing soybean plant.
 
Crop Insurance Considerations
William Edwards, ISU professor and ISU Extension economist, discusses crop insurance considerations given excess moisture.

Information on harvesting and tillage issues, crop diseases and grain quality and storage issues will be released in the next few days.

John Sawyer, ISU Extension soil fertility specialist and associate professor of agronomy, offers the following guidelines for managing soil fertility on wet cropland this fall and next crop season.

Soil Fertility
At this time of the growing season (late August), excess water impacts will be more important for crops to finish grain filling than on supply of nutrients since a major part of nutrient uptake has already occurred.

Looking ahead, excess water or ponding of soils should not affect results of fall sampling for routine soil tests and since we had growing crops all summer should not cause fallow phosphorus syndrome in next year’s crops. With the soil sampling after harvest, make certain the soils are dry so you can get good representative samples. Also, adjust down estimates of phosphorus and potassium removal for fields with significant yield reduction due to excess rainfall.

One effect of the excess rainfall this year, both from the spring and now the late summer events, will be less residual nitrate left in the soil profile. This means that next year’s corn crops should be responsive to applied nitrogen, and that for corn following corn, one should not count on extra carryover nitrogen. In some areas dry earlier in the summer, the excess wetness now has likely eliminated any need to try and account for carryover nitrogen. Research looking at nitrogen rate response in corn after corn automatically accounts for “typical” residual nitrate, so “extra accounting” should not be done.

More Disaster Recovery Information
Additional information on recovering from disasters in Iowa can be found at  www.extension.iastate.edu/disasterrecovery/.

-30-

Contacts :

William Edwards, Economics, (515) 294-6161, wedwards@iastate.edu
Roger Elmore, Agronomy, (515) 294-6655, relmore@iastate.edu
Palle Pedersen, Agronomy, (515) 294-9905, palle@iastate.edu
John Sawyer, Agronomy, (515) 294-7078, jsawyer@iastate.edu

Jean McGuire, Extension Communications and Marketing, (515) 294-7033, jmcguire@iastate.edu