In a word, the 2019 Minnesota growing season was wet.
Rains began at planting and continued off and on throughout harvest. Growing degree units were down 10% to 15% from normal. Thankfully, a killing frost held off until the second week of October, which allowed crops to reach physiological maturity.
Here are several situations we faced in 2019 and how they could impact the 2020 season.
1. Wet soils were good news and bad news. Nutrient availability and plant root growth were both compromised due to excessive water. If roots get too much water, they’re less likely to explore the soil. Also, when soils are wet, they are more prone to developing compaction during normal field operations.
If we had drier weather as the season progressed, it is possible that compaction layers would have still limited root growth in soils that experienced wet conditions during the past few years. So, although root growth was greatly limited by excess moisture, it was not fully impeded by compaction layers that become impenetrable as the soil dries out.
2. Weed control was marginal. Most farmers struggled to achieve good weed control. A few cornfields looked clean, but more had late-season weed emergence due to weather that hindered timely applications. Soybean fields with the Roundup Ready 2 Xtend trait platform had few weeds, provided farmers were able to spray before the June 20 deadline.
Developing a plan that includes using pre-emergence herbicides, multiple modes of action and soybean trait platforms can help you up your weed-control game in 2020. If you are a minimum-tillage farmer and didn’t get to a fall burndown, be sure to control those weeds as quickly as possible with a spring burndown or residual.
3. There were more soybean insects than just aphids. There was a general lack of aphid presence in soybeans in 2019. However, other insects — including Japanese beetles, green cloverworms and thistle caterpillars — took their place. Perhaps the lack of aphids in some areas was due to late planting and a cool, moist year that was not conducive to aphid reproduction.
4. Disease pressure was well managed with a fungicide application. Corn plants had minimal disease pressure. There was some eyespot, bacterial leaf blight and late-season anthracnose leaf blight. However, widespread northern corn leaf blight and gray leaf spot, typically among our primary corn diseases, were relatively absent in 2019.
In soybeans, bacterial leaf blight not controlled by a fungicide application was evident in the lower canopy of plants. There were also scattered areas of frogeye leaf spot and downy mildew.
Farmers who made fungicide applications saw the value of this investment, from a disease-management perspective and through an increase in photosynthetic efficiencies.
5. Management paid off. Between insects, disease and weather — or maybe in spite of them — by setting expectations accordingly, most Minnesota farmers actually had a fair crop year considering our conditions. Where farmers managed their acres — whether by applying an insecticide or fungicide, or by applying micronutrients or fertility — yield increases were evident.
6. There will likely be consequences for 2020. Soils were still wet when farmers harvested, which could cause extreme compaction and nutrient-limiting factors for 2020 crops, especially if we have a wet spring. Some of the leaf and stalk diseases that overwinter have a good chance of carrying over into 2020 crops. White mold, too, can overwinter and infect fields rotating into soybeans in 2020 if those fields had white mold incidence during the last soybean rotation.
Talk with your agronomist now about how to help mitigate these issues and start next season strong.
Zuk is a regional agronomist with WinField United in southern Minnesota. Contact him at firstname.lastname@example.org.