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Showing posts from August, 2019

Planning fall fertilizer following prevented planting situations

By: Dan Kaiser, Extension soil fertility specialist Prevented planting situations in parts of Minnesota have led to some questions about potential changes to fertilizer applications. Crediting fertilizer applied prior to the 2019 crop in prevented planting situations depends on the nutrients. Mobile nutrients such as nitrate and sulfate which were applied fall 2018 may not be there and may have been used by weeds or cover crops growing in fields this summer. If some carryover of nitrate is expected, a two-foot soil sample can be used to determine if any nitrogen should be credited. Nitrate can build in situations where a field is fallowed and no crop is grown due to mineralization of organic matter over the growing season. Crediting of phosphorus and potassium applied in fall 2018 can be done in prevented planting situations as long as plant material was not removed from the field. Phosphorus and potassium are held in soils and will be available for the following crop. If ph

Help, My Numbers are Falling

Reports of low falling numbers in HRSW are widespread.   The Hagberg Falling Numbers test (HFN) is a measure of the amount of α -amylase in the grain. Alpha-amylase is an enzyme that hydrolyzes polysaccharides like starch into simple sugars (glucose and maltose). A low HFN test value indicates that there is a large amount of α-amylase present in the seed, resulting in a very rapid breakdown of the starch in the ground wheat sample used in the HFN test, thereby allowing the plunger to fall rapidly through the slurry in the test tube. The HFN is used as an indirect measure of sprout damage in the harvested grain. Sprouted grain is problematic as a source of seed for next season as the germination and vigor will decline over time in storage.   Likewise, milling and baking quality are also affected as the α-amylase breaks down the starch in the endosperm and over time the α-amylase present will degrade and no longer be reactive when needed during fermentation. Unfortunately, the

Corn Development and Yield: Dry Conditions Can Reduce Kernel Size

By Jeff Coulter, Extension Corn Agronomist Much of the corn in Minnesota is in the dough stage of kernel development. At this stage and beyond, stress to corn from dry conditions reduces yield by decreasing kernel size. Kernel number is not reduced due to stress during the dough stage, since that has already been established. Corn development in Minnesota and much of the Corn Belt continues to remain behind that of last year and the 5-year average. Although warm temperatures advance corn development and reduce risk of corn being immature before a killing freeze, warm temperatures can shorten the duration of grain filling and therefore result in lighter kernels, especially when combined with dry conditions.  To evaluate the impact of this season’s weather on corn development and yield potential, researchers from the University of Nebraska ran a crop simulation model on August 21 for 37 locations across the Corn Belt, including three from Minnesota. Results are available a

Soil health tests

In this episode of the Nutrient Management Podcast, we discuss soil health tests .  What is the consensus definition of soil health? What should growers look for in soil health tests, and how should they go about testing their fields? What research is available in Minnesota tying soil health tests to crop performance and yield? Thank you to the Minnesota Agricultural Fertilizer Research and Education Council (AFREC) for their support of this podcast.

Late-season Pest Considerations in Northwest Minnesota

Welcome to the Fifth IPM Podcast for Field Crops – 2019 Welcome to the fifth IPM Podcast for Field Crops, 2019– this Podcast is sponsored by the UMN Extension Integrated Pest Management (IPM) Program.  In this week’s podcast, we feature Angie Peltier, UMN Extension Educator based out of Crookston, MN. Peltier provided insight on conditions in Northwestern Minnesota and the outlook into the remainder of the growing season for corn and soybeans. Diseases in corn, such as Goss's wilt or blight, have become a concern in some areas. It primarily affects leaves, preventing photosynthesis. As a bacterial disease, fungicides are not effective as a treatment, though crop genetics could play a role in reducing risk.       Goss’s blight in corn leaf. Lesions run parallel to leaf veins,  and dark water-soaked spots form within. Photo: Angie Peltier One insect gaining attention across the state this year in soybean is thistle caterpillar, or the painted lady butterfly, whi

Wheat Harvest: Drink more Coffee

Wheat harvest is underway. The long hours alone are probably enough to need an extra cup of coffee. However, that isn't the reason for me to encourage you to up your daily intake of coffee (or any liquids for that matter); once the combine is rolling there is little that will make you stop and take a break, except maybe when mother nature calls. Is that extra stop that I'm interested in creating. When taking that break, please take a few second extra and scout for wheat stem saw fly (WSS) damage. Check lodged areas of the field or individual stems that were pulled out of the canopy by the reel on the header for the telltale straight, razor-like, cut at the bottom of the stem just above the soil surface. When you split the stem open longitudinally, you will also find the stem filled with something that resembles saw dust. Please let me know if you find WSS in any of your fields as this helps us understand how widespread the problem is becoming.

Gopher Coffee Shop podcast: Conservation in agriculture

In this installment of the Gopher Coffee Shop podcast, Extension educators Ryan Miller and Brad Carlson sit down with Jill Sackett Eberhart, Board Conservationist with the Board of Water and Soil Resources (BWSR), to learn about Jill and her role with BWSR. We discuss conservation in Minnesota agriculture and comprehensive watershed planning to gain a better understanding of how conservation work has changed and how the process is working. Enjoy! Listen to the podcast The Gopher Coffee Shop Podcast is available on Stitcher and iTunes . For a chance to read about various crop management topics, please see our Minnesota Crop News blog: Sign up to receive Minnesota Crop News: For more information, visit University of Minnesota Extension Crop Production at .

Site-specific estimation of corn yield response to nitrogen fertilizer

Vijaya Joshi 1 , Jeff Coulter 1 , Kelly Thorp 2 , Gregg Johnson 1 , Paul Porter 1 , Jeff Strock 1 , and Axel Garcia y Garcia 1 1 University of Minnesota, 2 USDA-Agricultural Research Service Site-specific yield estimation is important for efficient management of agricultural inputs and explaining spatial yield variability. Current approaches for site-specific yield estimation include the use of historical yield maps (Fig. 1), crop simulation modeling, and remote sensing. Several years of historical yield maps provide information on spatial yield variability and help locate higher and lower yield zones in fields. However, the causes of yield variability may differ due to interactions among weather, crop management, and site characteristics such as soil type and topography. Figure 1. Corn yield map from 2016 (above) and legend (right). Source: Jodie Getting Crop models incorporate the effects of cultivar, soil, weather, and agronomic management, and simulate dynamic p

Assistance requested with plant sample collection to study soybean SDS pathogen distribution in Minnesota

Dean Malvick, Extension plant pathologist We are working to understand the distribution of the fungal pathogen that causes soybean sudden death syndrome and root rot of edible bean in Minnesota. Your help is requested in the collection of plant samples to enable us to determine where this pathogen/disease is spreading. We are focusing our sampling on areas north of Highway 12. Thus, we are interested in soybean samples with foliar symptoms of SDS as well as dry edible bean and alfalfa samples with symptoms of root rot from Northwest and Central MN. The soilborne fungus ( Fusarium virguliforme ) that causes sudden death syndrome (SDS) of soybean and root rot of edible bean and other legumes is spreading north in Minnesota. Symptoms of SDS on soybean include interveinal necrosis & chlorosis, defoliation which leaves petioles attached, and root rot (Figures 1 & 2). Our goal is to monitor and map the presence of this pathogen in soybean, dry edible bean, and alfalfa produc

Applying manure in late summer or early fall? Try cover crops

By: Melissa Wilson, Extension manure specialist, and Liz Stahl, Extension educator Thinking about applying manure soon on fields where short-season crops like sweet corn or peas have already come off or will be harvested in the next few weeks? Consider planting a cover crop to hold the nutrients in place this fall and next spring. Here are four potential options and some tips for combining a cover crop with a manure application: 1. Broadcast seed, then spread manure For solid manure that won’t be incorporated, make sure it isn’t applied too thickly so that the cover crop can push through.  For both solid and liquid manures, incorporation shortly after the manure is spread can help retain nutrients and improve seed-to-soil contact for the cover crop. Shallow incorporation will keep the seeds closer to the soil surface, leading to better cover crop establishment compared to deep incorporation or if the seeds were not incorporated at all. 2. Apply manure, then plant the co

Gopher Coffee Shop podcast: Crop and pest management

In this installment of the Gopher Coffee Shop podcast, Extension Educators Ryan Miller and Brad Carlson sit down with Bruce Potter, Integrated Pest Management Specialist, to discuss crop and pest management in MN. In this episode we discuss IPM and how are people making crop and pest management decisions. Topics included in the discussion: White mold, soybean aphid biology and management, and soybean gall midge (a new and emerging pest of soybeans in MN). Enjoy! Follow Bruce on twitter: @SWMNpest Read his newsletter here: Listen to the podcast The Gopher Coffee Shop Podcast is available on  Stitcher  and  iTunes .    For a chance to read about various crop management topics, please see our Minnesota Crop News blog: Sign up to receive Minnesota Crop News: For more information, visit  University of Minnesota Extension Crop Production at

Defoliating insects still making their presence known in Minnesota soybean

by Robert Koch (Extension Entomologist) While soybean aphid numbers have been generally low this year, defoliating insects (especially green cloverworm and thistle caterpillar) have been abundant in soybean fields across much of Minnesota. I have also received some scattered reports increasing defoliation from grasshoppers in northwest Minnesota and Japanese beetles in southeast Minnesota. To determine when to apply insecticides, rely on scouting and thresholds. Continue scouting through pod and seed development. Below is a summary of scouting and thresholds for defoliating insects from an earlier Crop News article. Thistle caterpillar on soybean  (photo credit Adam Sisson, Iowa State Univ., Green cloverworm on soybean (photo credit Adam Sisson, Iowa State Univ.,

Video: What source of sulfur is right for you?

About half of corn’s sulfur requirement is taken up between V5 to early silking. Only 10% of sulfur is taken up by corn prior to V5, but this timeframe is critical and deficiencies early in the growing season can limit yield – particularly in cool and wet springs. When needed, sulfur fertilization can produce profitable increases in corn yields. In this short video, Extension soil fertility specialist Dan Kaiser walks you through how to choose the right source of sulfur, and when and how to apply effectively. For more information, read our sulfur guide . --- Subscribe to Minnesota Crop News email alerts for research updates and current growing conditions. For the latest nutrient management information, like UMN Extension Nutrient Management on Facebook , follow us on Twitter , and visit our website . Support for this project was provided in part by the Agricultural Fertilizer Research & Education Council (AFREC).

Guidance for insecticide rotations for pyrethroid-resistant soybean aphid

by Robert Koch (Extension Entomologist) and Bruce Potter (Extension IPM Specialist) Soybean aphid populations have been generally low across Minnesota. However, populations in some fields in southwest and southeast Minnesota are nearing threshold levels and may require insecticide application to protect yield. In these areas, soybean aphid infestation levels very considerably from field to field, so you should rely on scouting and the economic threshold (80% or more of the plants with aphids, average of 250 aphids per plant, aphid numbers increasing) to determine when to apply insecticides for soybean aphid. As folks consider spraying fields for soybean aphid, we want to remind everyone that soybean aphid has developed resistance to pyrethroid (Group 3A) insecticides. Currently, any populations of soybean aphid in Minnesota should be considered potentially resistant to pyrethroids. Insecticide rotations are an important part of insecticide resistance management and may help reduce the

Cover crop strategies to improve nitrogen cycling in corn

by Hannah Rusch, Jeff Coulter, Julie Grossman, Gregg Johnson, Paul Porter, and Axel Garcia y Garcia Fig. 1. No cover crop (foreground) vs. an interseeded mixture of cereal rye + crimson clover + forage radish (background) at Waseca, MN in October 2018. Balancing the supply and demand of nitrogen (N) in crop production is challenging. In most cases, application of N fertilizer is needed to ensure that adequate N is available to corn. Nitrogen that is not taken up by plants can be lost from cropping systems as nitrate through leaching or runoff. Cover crops can help to manage nutrients within cropping systems. One function of cover crops is to capture available soil N by storing it in their tissues. The period between corn harvest and winter is limited by cool air temperatures and short days, making cover crop establishment following corn harvest a challenge. Interseeding cover crops into corn can increase the amount of growing degree days and solar radiation available for co

Be on the lookout for brown marmorated stink bug in soybean in southeast Minnesota

by Robert Koch (Extension Entomologist) and Rafael Carlesso Aita (Graduate Student) The brown marmorated stink bug (BMSB) has been detected in soybean fields in Dakota County, Minnesota for three years in a row. From 2016 to 2018, low numbers of BMSB adults and nymphs were collected in sweep net samples in those fields from mid-August to mid-September. During the pod and seed development stages, soybean is attractive to stink bugs and susceptible to their feeding injury. However, due to the low densities of BMSB observed in Minnesota the last few years, we don’t expect any substantial injury from this pest at this time. However, as populations of BMSB continue to spread and increase, it could become a pest that growers will need to actively manage, which is the situation in some of the eastern states. The purpose of this article is to inform you about the likely presence of low numbers of BMSB in soybean fields in southeast Minnesota. If you find any life stages of BMSB in your crops,

Fall fertilizer applications: What should growers be considering?

In this episode of the Nutrient Management Podcast, we discuss considerations for fall fertilizer applications. Given the conditions this past spring, if fertilizer was applied to a field which didn't end up getting planted, does fertilizer still need to be applied this fall for the 2020 crop? Is there anything new related to nitrogen which growers should be considering for fall application considering our recent wet growing seasons? What about P and K? And micronutrients? Listen to the podcast View the podcast transcript Subscribe to the podcast and never miss an episode on iTunes or Stitcher ! For the latest nutrient management information, subscribe to Minnesota Crop News, like UMN Extension Nutrient Management on Facebook , follow us on Twitter , and visit our website . Support for the Nutrient Management Podcast is provided in part by the Agricultural Fertilizer Research & Education Council (AFREC).

Corn development and yield: Stress now reduces kernel number

By Jeff Coulter, Extension corn agronomist Much of the corn in Minnesota has finished pollinating and the kernels are in the blister stage. Kernels enter the blister stage at about 12 days after tasseling and the milk stage at about 20 days after tasseling. In much of the upper Midwest, air temperature and soil moisture were favorable for successful pollination and are expected to remain favorable in the near term. Stress to corn during the blister and milk stages from dry or hot conditions can reduce grain yield by causing kernels to dry out, especially at the tips of ears. Some loss of kernels at the tips of ears is expected. Little or no kernel loss at the tips of ears after the milk stage indicate that the plant population for the given hybrid, site, and growing environment may not be high enough to maximize net return. Once kernels enter the dough stage, about four weeks after tasseling, kernel number is set and yield reductions from stress are due to lighter kernels. Corn

Alfalfa and potassium fertilization: What you need to know

By: Craig Sheaffer, Professor, Department of Agronomy and Plant Genetics; Jake Junger, Assistant Professor, Department of Agronomy and Plant Genetics; and Dan Kaiser, Extension soil fertility specialist Forage crops such as alfalfa remove large quantities of potassium (K) on an annual basis. When manure application is not an option, fertilizer must be purchased to supply K to alfalfa. Potassium can impact plant health, potentially affecting the ability of alfalfa to overwinter. Under-application of K can result in less tons produced per acre. While K fertilizer has historically been cheap compared to the other major macronutrients, supplying removal rates of K to alfalfa annually can result in a significant expense to alfalfa producers. Research funded by AFREC evaluated forage yield and quality at three locations across Minnesota with diverse climate and soil fertility. Alfalfa stands were harvested for four years beginning in the seeding year. What does the research say? E