For corn that is not yet planted:
- It’s too early to think about either switching hybrids or switching to another crop. There is still considerable time left before those become reasonable options. For more information on switching hybrids see Elmore et al., 2015).
- We all know that on average, as planting dates move into May, corn yields drop. What we need to remember is that 2016 may not be an average year! Indeed we may not yet have reached the best planting date for corn in 2016.
- Waiting for optimum soil conditions for early-season germination and seedling development is far better than “mudding in” corn.
For the 26% of corn that is planted:
- Corn seed subjected to soil temperatures at planting depth less than 50⁰F within 48 hours after planting may be subject to imbibitional chilling which may affect seedling germination. (See Specht et al. 2016.) Corkscrewing of seedlings (Figure 1) also may occur and seedlings may attempt to unroll below the soil surface (Figure 2). This can affect emergence timing and seedling performance.
- As corn emerges, assess stands carefully.
With the recent cool soil temperatures, corn will certainly emerge slowly and most likely irregularly. One “secret” of optimum yields is uniform emergence and early season growth and development. However, with reasonable plant populations, keeping stands with irregular emergence is better than replanting in most circumstances.If emerged corn encounters a freeze, yields may be reduced and the potential need for replanting needs to be assessed. (See McMechan and Elmore, 2016). Consider replanting with severe reductions in plant populations.