Yaodong Hu, Ph.D., FBN Data Scientist

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.

The relative maturity (RM) of a variety is supposed to give farmers a relative indication of how long that variety takes to get to harvest maturity. But the problem with relative maturity is that there is no standardized system by which seed companies assign relative maturities to their varieties.  Because seed companies may have different methods for assigning maturity numbers to varieties, varieties from different seed companies may not necessarily have the same season length even if they’re labeled with the same relative maturity. Also, many farmers worry that companies might not be fully transparent regarding maturity numbers, changing numbers slightly in order to fill gaps in their lineup or end up with a more marketable variety. Relative maturity can make seed decisions difficult The lack of transparency and consistency of current relative maturity values makes it difficult for farmers when they’re making seed decisions. At FBN, we've seen different brands sell the same variety in the same region with as much as a 5 "day" difference in corn, and half a maturity group in soybeans. On top of that, the units of relative maturity are confusing and widely misinterpreted 1 , since they are not actually calendar days between planting and maturity. Furthermore, seed companies typically assign a single national relative maturity rating, even though the actual season length required for maturity can vary by region. For example: 101 day corn grown in central Nebraska does not have the same season length as 101 day corn grown in central South Dakota. Farmers may end up not considering varieties that are actually well suited for their region if they only focus on relative maturity numbers. Substitute season length for relative maturity At FBN, a big part of our mission is testing conventional wisdom by putting it to the test through an unbiased analysis of anonymous, aggregated data from real farm operations. That’s why we're excited to supplement relative maturity with a very clear, quantitative, and simple metric of season length —simply, the calendar days between planting and the time when the crop reaches the typical harvest moisture for the region. FBN now shows the estimated Season Length of each variety personalized for a farmer's region in FBN Seed Finder. This leverages real-world data contributed by FBN farmers to measure how long varieties typically take to become ready for harvest. This number is shown next to relative maturity in Seed Finder, and is measured in the average number of days it takes that variety to go from planting to harvest in the enterprise's region. Read this next:  Turn the World Into Your Plot Trial with FBN Seed Finder ( 2 min read)  Season Length is currently available for corn and soybeans, and only for varieties and regions where there is sufficient data to run the analysis. Not all farmers will be able to access season length predictions for the same or all varieties. Since predictions depend on location, farmers need to have fields created in FBN to access predictions for their farm. Sources https://www.agry.purdue.edu/ext/corn/news/timeless/hybridmaturity.html FBN Direct Services are offered by FBN Inputs, LLC and are available only in states where FBN Inputs, LLC is licensed. FBN Crop Marketing is offered by FBN CM LLC and is only available where FBN CM LLC is licensed.