Corn Planting Dates and Replanting Considerations
The last two weeks have not been kind for much of the corn planted in Arkansas. Tremendous rainfall totals have fallen across most of Arkansas with many areas reporting 10 to 15 inches and some as high as 20 inches of rain. Only the far southeast corner of the state has received lesser amounts. Many fields have been flooded, are flooded, or will be flooded as some rivers continue to rise.
Will my corn survive the floodwater?
This has been a common question asked by many producers. This is a complicated question that has lots of factors involved. However, in general, fields that were submerged for 24 hours or less are likely to be fine, provided the soil does not stay saturated for days on end. In previous years, when corn is submerged by floodwater for 2-3 days, the corn has survived, especially if the temperatures are cool and the water has been moving. Corn that has been submerged for 4 days or more is less likely to survive (but still can). The cool temperatures that we have had in the last few days will likely help the corn plant hang on a little longer.
How late can I plant corn and expect good yields?
Some producers already know that they are going to need to replant corn (have contracts that they can’t get out of or have atrazine applied). Then the question becomes how much yield loss I am going to suffer when planting in mid-May compared to a traditional late March or early April planting. In the planting date studies we have conducted in the last few years mid-May planted corn has suffered little to no yield loss compared to earlier plantings with good management and irrigation in central and Northeast Arkansas. I know of several producer fields that have been planted in Northeast Arkansas as late as May 20th and still made 200 bu/acre. We had a corn research verification field planted May 20th a few years ago that also made slightly over 200 bu/acre.
Management Practices for Successful Late Planted Corn
1. Plant Bt Corn Hybrids when possible. Yield losses due to corn borers increase dramatically when planting in May compared to earlier plantings. Keep in mind that refuge requirements are still in effect. Whorl feeding from corn earworms and armyworms and kernel damage from corn earworms will likely be greater in May planted corn.
2. Hybrid selection. In general when planting later, full season hybrids tend to perform better. I would avoid hybrids that are less than 110 day in maturity. However choosing a hybrid with heat tolerance is probably more important than maturity within our typical maturity range of 111-120 day hybrids. Hybrids that performed well during last year’s heat are hybrids that seem to have good heat tolerance and should be considered. Last year’s University of Arkansas Corn Hybrid testing results can be found at: www.arkansasvarietytesting.com. Keep in mind that the later we plant, the taller the corn plant will likely be. Hybrids that are very tall when planted early in the season should be avoided. Only hybrids with good stalk strength should be considered
3. Avoid high plant populations. When planting in May, a greater percentage of plants will emerge (assume 95% emergence) compared to March or April planting. Since plants are going to be taller and likely have smaller stalks, excessive plant populations have the potential of causing lodging problems later in the season. Keep plant populations near 30,000 plants/acre.
4. Irrigate timely. Yes it seems odd talking about irrigating when we are looking at flooded fields, however, most years late planted corn will require more irrigation than early planted corn. Being timely and having the ability to supply adequate irrigation water is critical for maintaining maximum yields.
5. Budget for a foliar fungicide. In past years corn planted in May is much more likely to benefit from a foliar fungicide. Southern rust is much more likely to come in early enough in the season to cause yield loss.
6. Be timely with fertilizer and herbicide applications. Corn planted in May will develop much more rapidly than corn planted in March. For example, corn planted in mid-March at Marianna in 2010 took 76 days from planting to silking. Corn planted in mid-May only needed 49 days from planting for silking to begin.
7. Prepare for harvest now. Corn planted in mid-May will likely be ready to harvest in mid-September. As we get later in September, the 100 degree days that we hope for to dry corn down likely won’t be there. Grain bins and having the capability to dry grain becomes more important with later planting.