We’re looking at where farmers have been impacted by recent wild weather this spring, and to what degree, as well as analyzing just how much this spring’s planting delays deviate from the norm and, based on that timing, may impact expected yield.
1. Bad Spring Weather Has Significantly Altered Planting Plans
In our May 23 network poll, we asked FBN farmers if their corn planting has been affected by the historic wet spring. Many farmers said their planting was delayed, so they had to switch to a shorter-maturity variety, switch to soybeans, or avoid planting all together and take prevented planting crop insurance payments:
2. Extreme Spring Precipitation
What’s causing these problems? Rain, primarily. We compared this spring’s precipitation values to their historic averages in the map below.
Much of the Midwest has experienced precipitation that greatly exceeds historic averages:
These weather patterns are consistent with the FBN corn planting progress poll from May 28th, which is shown below. Regions where precipitation has significantly deviated from average are the same regions where planting is most severely delayed.
3. What Does This Mean for Yield?
Switching to shorter-maturity corn varieties is a possibility for some farmers, but it’s important to note that shorter-maturity varieties tend to have lower yields than longer-maturity varieties. FBN members can access variety-specific yield and season-length data in their region using FBN Seed Finder to help select varieties that are the correct season length for their region, and to understand the likely yield impacts of switching to a shorter-maturity variety.
Read this next: Should You Swap Corn Maturities When the Weather Puts You Behind Schedule? (4 min read)
Even if you’re not switching varieties, how much is a delayed planting associated with a change in yield?
We dug into USDA state-level yield and planting date data from 1986-2018. For each year and each state, we calculated when the state reached 50% planting progress, and compared that date to the average date that state reaches 50% planting progress (using the preceding 5 years).
In the graph below, negative planting dates mean planting was earlier than trend, and positive ones mean planting was delayed. Then, we calculated how much the yield from that year deviated from the state-specific yield trend, and compared those deviations to the planting date deviations.
Up until about a 5-day planting delay, we observed little association between planting date and yield.
After that, we observed a roughly 1 bushel per acre drop in yield for each day planting was delayed.
In 2019, national corn planting progress reached 50% about 2 weeks later than normal. It’s important to note that these are average associations with yield; there is still significant uncertainty in yield that is explained by in-season weather, or pest and disease issues that cannot be determined from planting date alone.