June 25, 2015
Areas of Concern for the 2015 U.S. Corn and Soybean Crops
With continued wet weather across the central and eastern Corn Belt, concerns are mounting that the saturated conditions could adversely impact the corn and soybean crops. The wettest areas of the Corn Belt are in eastern Iowa, across central and northern Illinois, northern Indiana, and western Ohio. Another region of wetness includes eastern Kansas and western Missouri. Some of the wettest areas are approaching record rainfall for the month of June.
Some of the concerns about the wet weather include the following:
Reduced acreage - The immediate concern is for the amount of intended corn and soybean acres that may not be planted due to the wet conditions. Most of the unplanted corn was reported in the states of Missouri and Kansas. The prevent plant date for insurance coverage for corn has already passed in those two states and it is assumed that some of the intended corn acres will be claimed under insurance or switched to other crops such as soybeans or grain sorghum. The prevent plant date for soybeans has passed in the central Corn Belt and it will occur on June 30th for the more southern locations. Farmers may still plant their soybeans past the prevent plant date, but their crop insurance coverage will decline 1% per day for each day that planting is delayed up until 25 days after the prevent plant date.
As of last Sunday, there were more than eight million acres of soybeans that had not been planted in the U.S. Of the total, approximately 5-6 million are double-crop soybeans planted after the wheat is harvested with the remainder being full-season soybeans that farmers have not been able to plant due to wet conditions. In the more southern locations, soybeans could still be planted for another 2-3 weeks, so there is still time to plant the soybeans if the weather would turn dryer. Unfortunately, the near term forecast is calling for more rainfall in the same areas. Therefore, there is a distinct possibility that not all the intended soybean acreage will in fact be planted.
Ponding and drowned out crops - The other immediate concern is for ponding and drowned out spots that would need to be replanted if it dries out in time. Ponding has been reported in all the states mentioned above and unfortunately with more rain in the forecast, so these areas will not dry out any time soon. If a corn plant is completely submerged under water for 2-3 days, the plant will die. If the corn plant is only partly submerged, it could survive for a few more days if the water drains away. Small soybean plants will not survive if they are submerged for more than 36 to 48 hours. Even if the plants don't die due to short-term ponding, the saturated conditions could result in increased disease pressures later in the growing season.
Loss of nitrogen - The saturated conditions are also resulting in a loss of nitrogen. If the soil is saturated for two or more days, the nitrogen can start to be either leached downward below the root zone or it may volatilize as a gas. Either way, a loss of nitrogen will have a negative impact on corn yields because generally it takes a pound of nitrogen to produce a bushel of corn.
Variable yields - The saturated conditions across the Corn Belt are going to result in highly variable yields depending on the local conditions. In saturated areas of the field, the crops could be slow growing and stunted due to a lack of oxygen in the root zone, while other better drained areas of the field could have excellent yields due to the abundant moisture. This increased variability will make yield predictions very difficult until the crop is actually harvested.
Shallow rooted crops - The abundant moisture is going to result in shallow rooted crops which could make the crops more susceptible to dry weather later in the growing season. Some moderate dryness early in the growing season is actually good for the crops because it forces the roots to go deeper into the subsoil in search of moisture. In saturated soils, the roots stay close to the surface, so if the topsoil dries out too quickly, the crop could be susceptible to moisture stress. Currently, the crops in the central and eastern Corn Belt are being stressed by too much water, but that could change going forward.
What both the corn and soybean crops need in the central and eastern Corn Belt are two weeks of warm and sunny weather, but unfortunately that is not in the forecast at the present time.