Minnesota Crop News

By: Dan Kaiser, Extension nutrient management specialist With low corn and soybean prices, I have been looking at some of our long-term data to figure out how growers can reduce fertilizer costs. One study I have not spoken much about is a long-term trial that was started in 2011 at the Southwest Research and Outreach Center in Lamberton, Minnesota. Data from this study show some interesting insights on starter fertilizer containing phosphorus (P), potassium (K), and zinc. About the study Initially, the study was established to look at fertilizer additives used in combination with starter fertilizer, and one thing that is unique about this site is that the soil pH is very acid, testing below 5.0. I have maintained the study over time to look at reduced rates of P and K with and without a P and K starter fertilizer in a three-year corn-corn-soybean rotation. The broadcast treatments for the first six years were similar, focused on application of removal rates of P and K for the corn cro...

Kathleen Hall, Ph.D., Minnesota Department of Agriculture, Research scientist, reviewed by Tana Haugen-Brown, UMN Pesticide Safety and Environmental Education Extension educator, Sally Raymond, UMN Pesticide Safety and Environmental Education Extension educator, and Jolene Warnke, UMN Pesticide Safety and Environmental Education Extension educator Monitoring is crucial for assessing and protecting water quality. Each year starting in May, Minnesota Department of Agriculture (MDA) staff and their collaborators head out to rivers and streams across the state to begin collecting water samples. These samples are then sent to the MDA's lab, where analysts test the water for 185 pesticide chemicals, including a variety of herbicides, fungicides, and insecticides, as well as their breakdown products (also known as degradates). The results from these monitoring efforts provide valuable information that the MDA uses to evaluate the impacts of routine pesticide use on Minnesota's water r...

Nitrogen loss is the topic today on the Advancing Nitrogen Smart podcast . Soil conditions and chemistry are factors that make nitrogen prone to loss, but how does the N loss process actually happen ? What's left over in the field after that process occurs, and where does the lost nitrogen go? What do denitrification, leaching and volatilization mean? How can the 4 Rs (right rate, right source, right placement, right timing) help growers minimize risk? How do nitrification inhibitors, microbes, and soil types fit in to the picture? All that and more in today's conversation. TRANSCRIPT Guests: Brad Carlson, Extension educator (Mankato) Dan Kaiser, Extension nutrient management specialist (St. Paul) Additional resources: Wait, consider your options before applying nitrogen this fall Video: What to know about nitrogen inhibitors and other enhanced efficiency fertilizers Field Notes talks about what to expect after heavy June rains Video: Fall vs. spring urea in Minnesota Nitrogen ...

The Pope and Stearns Soil and Water Conservation Districts and the Minnesota Department of Agriculture invite producers, landowners, and local partners to attend the upcoming Rosholt Research Farm Field Day on Thursday August 21, 2025, from 9:00 a.m. to 1:00 p.m. in Westport, MN. This educational event will highlight current research trials and practical innovations in soil health and nutrient management. Presentation topics include: Nitrogen use in irrigated corn with cover crops Efficient irrigation and nitrogen management strategies Interpreting soil moisture data, variable rate, probe technologies Soil health assessment and wind erosion demonstration Drone cover crop seeding demonstration Date & Time: Thursday, August 21, 2025 from 9:00 a.m. to 1:00 p.m.  Location: The Rosholt Research Farm: 910 OLD HWY 28, Westport MN 56385 Cost: There is no cost to attend. A free lunch will be provided. Registration: Register here . Registration is required, and we encourage you to sign u...

 Anthony Hanson - Field Crops IPM Extension Educator, Jochum Weirsma - Small Grains Extension Specialist & Angie Peltier - Crops Extension Educator Within the past week there have been widespread reports of true armyworm infestations reaching damaging levels in wheat fields across western Minnesota. There appear to have been multiple flights of true armyworm moths in the past few weeks hat have resulted in these large numbers of hungry caterpillars feeding on grasses leading to yield loss in wheat fields by defoliating leaves and clipping wheat heads (Fig. 1). Figure 1. True armyworm larvae feeding on wheat heads and leaves in a Becker County, MN field in late July. Photo: Jordan Hunnicutt - 2025 IPM scout. Both UMN pest scouts and farmer reports indicate these outbreaks are at least in west-central and northwest Minnesota. Most of the crop is completing development at this point, but yield loss is still possible until harvest with this pest. Heavy defoliation was reported in ...

Phyllis Bongard, Educational content development and communications specialist, and Dean Malvick, Extension plant pathologist While some crop disease has been reported, most corn and soybean diseases are still in the early stages of development. Most of the diseases that cause significant issues may start appearing in the next week or two. To help know what to watch for, Dr. Dean Malvick discussed several corn and soybean diseases, conditions that favor them, and their management options in the July 23rd Strategic Farming: Field Notes episode. Soybean diseases White mold White mold, a potentially damaging disease, is favored by rain during the flowering stage. However, it prefers cool temperatures for development and while there have been a few cool nights, the warm temperatures we’ve been experiencing may slow its progression. Watch for this disease, especially if cool weather and more rain is in the forecast. Cultural practices that speed canopy closure, such as planting in narrow r...

By: Vasudha Sharma, Extension irrigation specialist As we move through this growing season, one question we often hear is: “How are we doing this year compared to normal?” While each season brings its own set of challenges, comparing this year’s crop evapotranspiration (ET) and atmospheric demand to long-term averages provides critical insight into irrigation timing, water availability, and crop stress risk. Reference Evapotranspiration (ET o ) or Atmospheric Demand Let’s begin with an overview of atmospheric demand, also known as reference evapotranspiration. Reference evapotranspiration (ET o ) is a fundamental metric in agriculture used to estimate the atmospheric demand for water from a well-watered reference crop, usually grass or alfalfa. It reflects how much water a crop would require to grow optimally under ideal soil moisture conditions. ET o incorporates the effects of weather factors such as temperature, solar radiation, humidity, and wind, combining both evaporation from t...

by Dean Malvick, Extension Plant Pathologist Hail damage has recently occurred to corn in parts of Minnesota. Some producers and crop consultants are asking about the potential value of applying foliar fungicides to corn damaged by hail. This article will cover key points on this topic. Why might applying fungicides to hail-damaged corn be beneficial? A common misconception is that hail damage opens the corn plants to infection and disease that can be controlled with fungicide applications. Few corn diseases in Minnesota are increased by hail damage except for common smut, Goss’s leaf blight and wilt, and possibly stalk rots. However, none of these diseases have been managed effectively with foliar fungicides. In addition, a study in Iowa found that foliar disease was lower in corn plots with simulated hail damage. What does the available data show about the potential value of fungicides applied to corn damaged by hail? The published results from field studies indicate no significant b...

It isn't hard to find Fusarium Head Blight (FHB) or Bacterial Leaf Streak (BLS) across much of Minnesota.  BLS is appearing relatively late in the grainfill period, and yield losses caused by the disease will be relatively small.   The same cannot be said for FHB, as the conditions continue to favor disease development. The best time to assess how many early infections occurred is probably this week.  These early infections result in the characteristic tumbstone kernels. These tombstone kernels can be easily removed during combining, and it is the simplest and cheapest way to reduce the amount of deoxynivalenol  (DON) in the harvested grain. Unfortunately, it's too early yet to see if the current stretch of favorable conditions will result in many late-season infections. Late-season infections are more difficult to deal with as the infected kernels have a near-normal appearance and weight but contain enough deoxynivalenol  (DON) to result in discounts or re...

The optimum time for pre-harvest management in small grains is right at or just after the crop reaches physiological maturity (PM). This applies regardless of whether you swath the grain or apply glyphosate as a pre-harvest treatment. At PM, the crop has the maximum kernel dry weight. No additional dry matter will be deposited into the grain. The kernel moisture percentage at physiological maturity is relatively high, and can vary from 20 to 40 percent. Research has shown that swathing just before PM doesn’t harm grain yield or quality. However, this practice isn’t recommended when using glyphosate as a pre-harvest tool. There are two visual indicators you can use to determine whether the crop has reached PM: 1) Loss of green from the kernel - The first indicator is the loss of green in the kernel, and the appearance of a dark layer of cells or pigment along the crease (Figure 1). Kernels in the same spike will reach physiological maturity at different times, with the middle of the hea...

Northwest Minnesota saw two unusually cool mornings last week, with minimum temperatures dipping well below 50°F  on Wednesday and Thursday morning (Figure 1). This is a cause of concern for the earliest-seeded spring wheat. Warmer temperatures during grain fill will result in higher Hagberg Falling Number (HFN) values.  Conversely, cooler temperatures will yield, on average, lower HFN. A short period of very low nighttime temperatures (< 50°F) very late in the grain fill period, however, is enough to yield a disproportionate increase of α-amylase in the seed. This phenomenon is referred to as late-maturity α-amylase (LMA).  Figure 1 - Daily minimum temperature recorded by NDAWN weather stations across eastern North Dakota and northwestern Minnesota on June 16th, 2025. LMA is a recessively inherited trait. In standard height wheat varieties, the expression of the trait is constitutive, allowing breeders to effectively select against the trait. In semidwarf wheat variet...

By: Eduardo Garay Lagos, On-Farm Research Manager and Outreach Specialist The University of Minnesota Manure Team is excited to host two Commercial Animal Waste Technician (CAWT) recertification training course options: in-person on August 7th, 2025, and online through October 31st, 2025.  With a growing focus on environmental sustainability and safe manure management practices, this course is crucial for staying informed on both regulatory updates and safety protocols.  The Minnesota Department of Agriculture (MDA) emphasizes that all training must be completed by November 1st to get CAWT recertification for licensure through the Minnesota Department of Agriculture (MDA). Anyone who fails to complete the course, whether in person or online by the October deadline, will need to retake the certification exam to renew their licensure.  In-person CAWT recertification: August 7th, 2025 only The final in-person Commercial Animal Waste Technicians (CAWT) recertification course ...

Dr. Fei Yang, University of Minnesota, Extension Corn Entomologist, and Dr. Yucheng Wang, University of Minnesota, Research Associate Northern corn rootworm will leave corn to  forage on other plants. Photo: Bruce Potter Corn farmers in Minnesota continue to face significant challenges from the corn rootworm (CRW) complex, primarily the Northern Corn Rootworm (NCR) and Western Corn Rootworm (WCR). Crop rotation has traditionally been a reliable method for managing CRW, as adults predominantly lay eggs in corn fields and the larvae survive only on corn roots. Rotating corn to other crops will disrupt the CRW life cycle and eliminate local populations. While significant Minnesota WCR populations have been limited to continuous corn, a subset of NCR has adapted to crop rotation through an extended diapause trait, which allows eggs to remain dormant in the soil for two or more winters. This adaptation enables larval survival in rotated fields when corn is planted every other year....

On this episode of Advancing Nitrogen Smart , Brad and Dan take some of the mystery out of variable rate nitrogen. What are we trying to accomplish when we use a variable rate management practice? What kinds of field conditions might benefit from VRN, and which conditions should be avoided with VRN? How might the other 3 R's (Timing, Source & Placement) play a part in variable rate decision making? All that and more on today's show.  TRANSCRIPT Guests: Brad Carlson, Extension educator (Mankato) Dan Kaiser, Extension nutrient management specialist (St. Paul) Additional resources: Is variable rate nitrogen based on yield maps a good idea? Variable rate nitrogen: What farmers should know Making sense of Minnesota’s corn fertilizer guidelines: Frequently asked questions and answers Fertilizing corn in Minnesota Nitrogen Smart --- Click here to listen to all Advancing Nitrogen Smart podcast episodes. For the latest nutrient management information, subscribe to the Nutrient Man...