What the Iowa Derecho Taught Us

By Dustin Brucker

In the weeks and months following the mighty winds that swept through central and eastern Iowa in August – known as a ‘derecho’ event – many farmers have been left with devastation to both crops and property. Many fields were completely destroyed. Of Iowa’s 99 counties, 36 were hardest hit and an estimated 3.57 million acres corn and 2.5 million acres soybeans were damaged, accounting for approximately 20% of Iowa’s cropland. Estimates range from 200-400 million bushels of grain was lost from the event. Additionally, the sustained winds of 60-100 mph caused damage to numerous grain storage facilities, totaling approximately 100 million bushels of storage potential just ahead of harvest time.

While derechos don’t happen regularly, severe weather events seem to be more and more frequent. So, in this post, I wanted to share a few lessons we learned, in the hopes that they might help someone else in the future.

Insurance options on crop land

While short-term questions were answered by local agronomists and insurance adjusters, many growers are interested in future events and how to best mitigate against crop loss. Based on insurance determinations, corn growers were offered to harvest at a severe loss or crop-destruct and collect based on a range of recent crop production data points.

Most farmers in the Midwest have crop insurance in one form or another to protect themselves and their crop from naturally occurring events like flood, drought, hail and wind. However, not all growers purchase all options for every acre. Incremental-occurrence insurance can get costly, especially when margins are lower like they have been the past few years. Trying to cover all possible scenarios in a growing cycle can quickly outweigh returns. Multi-peril options can cover a variety of combinations up to complete coverage for a farm to mitigate against yield loss and loss of revenue.

Attributing actual yield loss for the crop this year was difficult. Much of Iowa had already been under severe drought conditions leading up through June, July and August. Though the derecho caused significant damage to the plant with widespread lodging, the corn plant’s seed-set had been established. Projected yield was already determined by the time of the event – August 10 – and the growth stage was transitioning within R3 (milk) and R4 (dough) stages. A rough estimate of the plant’s yield potential was already projected up until the event, but still needed help finishing out.

My big takeaway from Iowa’s experience was to always have a good relationship with your insurance partner, but also know that they’re always happy to sell you something new. Make sure you are clear on what each product covers (some products sound like they cover what you’re looking for, but they actually don’t) and double-check that all scenarios are spelled out before making a decision to purchase. Be smart about it, but remember: extreme weather events are becoming more frequent, and insurance against those can help protect your operation’s long-term viability.

Management decisions after mid-season destruction

Growers were challenged with how to handle their acres after receiving confirmation numbers from insurance claims. If a field was determined to be ‘totalled’ or ‘zeroed’ by the adjuster, he could till the crop in and collect the insurance or wait for a suitable harvest window and combine, haul, and store the grain. Those who opted to till in the downed corn will face a challenge next season with volunteer seed germinating and becoming a weed in the next cash crop. Those who attempted harvest saw more challenges with a significantly slowed harvest pace from one-directional harvesting, greatly increased disease pressure from hail-damaged ears and lodged corn stalks, as well as the added volunteer corn risk the next year from fallen ears at harvest.

“Expect the unexpected” is thrown around a lot but – in this type of situation – it’s true. What we learned with the derecho is, while we want to continue planning for the year like normal, we need to have enough knowledge and flexibility to adjust the plan in case of loss due to flood, wind or drought (at any time of the year). Remember that trying to maximize economic returns on your farmland (beyond simply chasing yield) requires agility and preparation throughout the year – not just in the spring.

Soil health: tillage decisions with downed corn

One thing to consider when challenged with a downed-corn scenario is the potential to improve or maintain soil health. We know having live roots in the soil, maintaining ground cover, and minimizing tillage are significant tools to help build good soil health. When challenged with flat corn mid-season (after pollination), growers need to break open the stalks to promote decomposition while also minimizing soil disruption.

Remember: we do not want to sacrifice long-term soil health for a one-time event. A grower may be tempted to incorporate the downed crop into the ground to accelerate breakdown of plant biomass and germinate downed grain. However, turning over the soil can destroy the work of building good soil structure and negatively impact the biome for our beneficial microbes. Additionally, an early season (V2-V6) herbicide pass to control the volunteer corn will almost certainly be a part of the following year’s management plan (with a second pass highly likely), so burying the seed is not critical to ensuring a quality crop the following year.

Vertical tilling offers the chance to chop and size the residue while also leaving the ground largely untouched. Crop destruction earlier in the life cycle – further from maturity – also alleviates the growth potential of the corn seed the following season. The challenge this year was the timing of both the event and the delayed response and confirmation from insurance companies. The large volume of service calls meant that many growers did not have their answer in writing early enough after the event to move quickly. You should never till under a crop with just a verbal confirmation from the adjuster – always have it in writing!

Soil health: cover crop seeding options in high residue

The second opportunity to build soil health in a downed-corn situation is with cover crop seeding. The sooner the cover crop can be seeded and start establishing roots, the better. Many growers like to fly on cover crops with aerial seeders or high-clearance ground seeders. When a crop is destroyed mid-season, we have a lot of residue to consider. Ensuring good seed-to-soil contact is critical when seeding cover crops, so drilling may be a better option if a grower must contend with significant residue on top of the ground. Some research has shown that aerial applying the cover crop seed PRIOR to tillage in a downed-corn scenario has good results. This is because, while the corn is lodged, it is not yet flat on the ground and seeds dropping from altitude can still reach the soil. Chopping the stalks shortly thereafter can help put some soil on top while also creating space for the plant to grow. Dropping seed on top of the chopped residue does not let the seed get that good soil contact.