Category Archives: Guest Blog
Corn Emergence and Growing Degree Days: For this week’s column, I’m going to share information my colleague, Nathan Mueller, Extension Educator in Saline, Gage, and Jefferson counties wrote in his recent blog post. “Many factors affect corn growth and development, especially early in the growing season. A common question this time of year after corn is planted and some fields have emerged whiles other have not is “How many Growing Degree Days (GDD) does it take for my corn to emerge?” Since corn emergence is directly related to soil temperature (and of course soil moisture), the days to emergence vary especially when one compares early planting dates to later planting dates. The general assumption is 120 Growing Degree Days abbreviated GDD for corn to emerge under favorable conditions. However, we know that some planting practices and environmental conditions can decrease or increase the amount of GDD needed for corn to emerge. We use the GDD calculation for air temperature to estimate how long it will take corn to emerge even though soil temperature is the driving factor.
Growing Degree Days (GDD) or Growing Degree Units (GDU) calculation is determined from air temperature. The corn equation for GDD or GDU = (Daily Maximum Air Temperature + Daily Minimum Temperature)/2 – 50. When the maximum air temperature is greater than 86 degrees, we set the value at 86 in the equation, as the growth rate of corn does not increase much beyond 86. Likewise, when minimum air temperature is less than 50 degrees, we set the value equal to 50 in the equation. The sum of daily GDD or cumulative GDD for corn emergence is approximately 90 to 120 under favorable conditions. As a base line for GDD required for corn emergence, colleagues at the University of Wisconsin report that 125 GDD are required for emergence. Based on research in Iowa, corn typically required 90 to 120 GDD from planting to emergence. This range assumes adequate soil moisture and will vary with planting depth, tillage system, and residue cover.
Research shows some adjustments are needed to help fine tune expected emergence dates based on GDD determined from air temperature. Planting practices that change the amount of GDD for corn to emerge include planting date, depth, and residue cover (view full table of variables at https://cropwatch.unl.edu/growing-degree-units-and-corn-emergence). It takes about 10-25 more accumulated GDD for emergence with early planting dates. Planting deeper than 2 inches will increase the number of GDD to emergence by about 15. More than 75% residue cover increases the accumulated GDD needed for emergence, ranging from 30 to 60 GDD more. Additionally, the soil moisture, soil condition, and soil texture change the needed GDD for corn to emerge. Dry seedbed conditions will require more GDD. Crusted or cloddy soils can increase GDD by 30 more. Heavy textured soils require more GDD than do coarse textured soils. Corn genetics also can affect GDD needed for emergence. Therefore, the amount of accumulated GDD from planting to corn emergence can range easily range from 90 to 200 GDD.
In Nebraska, the U2U tool (https://hprcc.unl.edu/gdd.php) can be used to determine local accumulated GDD based on your planting date. For example, at the tri-county corner of Saline, Jefferson, and Gage counties from May 1 to May 13, we accumulated 114 GDD and the 30-year average is 139. In summary, remember that numerous factors drive corn emergence and assuming a standard 120 Growing Degree Days (GDD) for corn to emerge will not always hold true.”
Tree seeds and leafing out: I’ve been watching silver/red maples and ash trees noticing that some, including one of mine, is very heavy in seed production like what we experienced in 2019. There’s also quite a range in oaks with some leafing out normally and others leafing out rather slowly. I think the seed production possibly is due to the warm March. Information from Ohio State shared that, “Every spring, maple trees produce small flowers that turn into seeds. Normally, a cold frost kills some blossoms, but this year the usual chill didn’t arrive at the right time. More blossoms than usual turned to seed.” Oaks leafing out at different rates could be due to the fact we’ve had a cool April/May and it’s also a survival mechanism to not all leaf out at once. We’ve also been experiencing some oak decline (which is also observed in August when leaves prematurely turn brown), and this can also result in slower leafing out. These are just some thoughts; I really don’t know the answers, just sharing that for those who are asking, I’m also observing this.
Purple flowering henbit is blooming right now. Spring has officially sprung. The crabapples and flowering pears are nearing full bloom. Tulips and daffodils are starting their flower show. Henbit and dandelions are looking gorgeous. Are the last two not quite the kinds of spring flowers you want in your landscape? If so, there are some […]Henbit, Crabgrass, & Ground Ivy… Oh My! — Husker Hort
Leasing land for solar development is a topic landowners in the McCool Junction and Lushton area are facing. This is a guest column by my colleague John Hay, Nebraska Extension Energy Educator.
Renewable energy has increased significantly in recent years and the number of wind farms and size of wind turbines are a visual reminder of renewable development. Due to higher development cost, solar electric systems, also called solar photovoltaic (PV), have lagged in commercial electric development. In recent years, the dramatic price decline of solar PV has led to greater interest in utility scale solar development. For instance, consider a 5-Megawatt system similar to the one constructed West of Lincoln North of I-80. Based on solar cost benchmarks published by the National Renewable Energy Lab, a 5-Megawatt system constructed in 2010 would have cost $27.6 million dollars, compared to $5.65 million dollars to construct the same size project in 2018. Combine this with the 26% federal tax credit and the economics of utility scale solar are sufficient for major development interest across the nation. The federal tax credit is currently 26% and set to decline to 22% in 2021, then 10% for future years.
Utility scale solar farms are constructed on open ground generally near access to the electric transmission grid. Other considerations for siting solar farms may be the solar resource, proximity to electricity demand, other local incentives, and regional value of electricity. Access to land is an early step in utility scale solar development. Farmers and landowners in Nebraska are being approached to lease land for solar development and these landowners are facing important long-term decisions about the future of their land. When considering a solar leasing contract many factors should be considered. According to the Farmland Owner’s Guide to Solar Leasing published by the National Agricultural Law Center these considers are: Length of the commitment, Who has legal interests in the land?, Impacts on the farm and land, Family matters, Property taxes, Government programs, Liability and insurance, and Neighbor and community relations.
Utility solar farmland leases are long term contracts and need to be reviewed by a qualified attorney. In Nebraska these leases can be as many as 40 years and longer if extended. For many landowners this long-term contract may extend into the next generation and should be discussed with family. Landowners at times feel pressure to sign contracts and this can be stressful. Take the time to review and negotiate these contracts and always know that saying “no” is an option.
Solar leases can be attractive to landowners as they can offer long term income and profitability on the leased land. A study in Michigan of landowners with wind farm leases showed farmers with leases invested more in their farms than farmers without leases. This suggest the lease income may influence farm stability and longevity. Solar farms like wind farms add to county tax income. These developments are exempt from property tax and instead have a nameplate capacity tax paid each year in place of the property tax.
Utility scale solar farms are unlike wind farms in some ways. For example, wind turbines may take only 1-2 acres out of production per turbine because farmers can farm around the base of the turbine and turbine access road. In comparison, a 1,000 acre solar farm will take all 1,000 acres out of production. Solar farms are low to the ground and have less impact on the skyline. Generally solar farms will be fenced with vegetation growing amongst the solar panels. Vegetation could be perennial pollinators, grass, or weeds. Common management is periodic mowing to ensure plants do not disrupt solar operation and production.
Landowners approached about solar leases should seek advice from an attorney and take time to thoroughly consider the contract and its implications to their farmland. Review of the Farmland Owner’s Guide to Solar Leasing published by the National Agricultural Law Center will help frame the issues and considerations for solar leases. This can be found at: https://farmoffice.osu.edu/sites/aglaw/files/site-library/Farmland_Owner’s_Guide_to_Solar_Leasing.pdf. For additional questions about solar leasing, please see https://cropwatch.unl.edu/bioenergy/utility-scale-solar, or contact John Hay, Extension Educator at 402-472-0408 or firstname.lastname@example.org.
With the recent sprouting of grain on the ears and with more producers now learning what percent loss their crop insurance is determining for each field, I felt it would be good to talk about feeding this damaged grain again. This post is written by Dr. Dee Griffin, DVM at UNL’s Great Plains Veterinary Education Center at Clay Center. I appreciate Dee’s willingness to provide this information from a Veterinarian’s perspective.
Also a note, to date we have not found Aspergillus in our hail damaged fields. The grain molds we are seeing are Diplodia and Fusarium. Diplodia does not have the potential to produce mycotoxins. Fusarium has the potential of producing fumonisin, vomitoxin, or DON. You can bring forage samples to Husker Harvest Days this coming week to the IANR building and have them tested that day for nitrates for free if you wish.
Dr. Griffin writes: Any time a growing grain producing plant is damaged there is a potential for changes in the plant or grain on the plant contaminated with fungus/molds to grow. The most common change in stressed plants is the accumulation of nitrates. Aspergillus or Fusarium will be the most likely fungi to be contaminating harvested grain from storm damaged corn in our area.
It is really important to know that most molds are not toxic. Therefore just because mold growth is observed doesn’t mean the feedstuff will harm livestock. Even though a mold may not be toxic it can still cause feed refusal. Not all livestock species are equally sensitive to mold contamination and not all production groups are equally sensitive. For instance pregnant and young animals are more sensitive than mature non-pregnant animals.
Nitrate accumulation in stressed plants can cause be harmless or cause serious harm depending on:
- the level of nitrate in the feed harvested from stressed plants,
- on the life stage of the animal,
- and on the species of animal.
Nitrates accumulate in the forage portion of the plant, so nitrates are not a concern in grain harvested from stressed plants. Additionally, it is important to know nitrate levels will always be highest in the bottom part of the plant and lowest in the top foliage. Nitrate testing is simple and reasonable quick. Your local UNL Extension Educator can help you locate the nearest facility that does forage nitrate testing.
Feed containing nitrate levels less than (<) 1000 parts per million (ppm) seldom are associated with an animal health concern. Feed containing nitrate levels greater than (>) 1000 ppm may be a concern in younger animals and levels >2000 ppm should not be fed to pregnant cattle. Feeder cattle are reasonably resistant to nitrates but feeds containing >4000 ppm should not be fed to any animals.
Molds in corn grain of concern could be either Aspergillus or Fusarium. Your UNL Extension Educator can be a great help in identifying mold growing on ears of your storm damaged corn before the grain is harvested. Both of these fungi are potentially dangerous when found in livestock feed. Toxins produced by molds are extremely stable, therefore if a significant level is found, the level will not decrease over time. Silage produced from damaged plants and grain harvested from mold infested plants is potentially a problem.
Good silage management is critical to lessen the likely hood of continued mold growth after ensiling. Proper packing to remove oxygen and improve fermentation which ensures the pH will be below 4.5 is critical.
You can’t look at harvested grains from storm damaged fields and visually identify mycotoxins. Corn grain from storm damaged fields can … and mostly likely should … be tested for mycotoxins before feeding to livestock. Your local UNL Extension Educator, nutritionist or veterinarian can help with mycotoxin testing.
Proper sampling is crucial to getting reliable results back from the laboratory. A “grab sample” is not adequate. The sample submitted to the lab should be representative of the entire load, bin, pit or pile of feedstuff being evaluated.
The steps are simple
- If sampling a field before harvest, sample at least two dozen ears that appear to have mold growth and submit all the ears to the laboratory for mycotoxin evaluation
- If sampling after harvest, take multiple samples uniformly from throughout the silage or grain in question
- The sample should be taken from what would be used in a single load of feed
- That means, if five loads of feed could be made from a 50,000 lb semi-load of corn, collect not less than five samples from the semi-load of corn
- The sample should be based on sample volume not weight
- For instance, collect “coffee can” size samples
- Mix all the all samples together that were collected from the feed in question
- For instance, if 10 coffee can size samples were collected from across the face of a silage pit, pour all 10 samples onto a plastic sheet and thoroughly mix them together
- Next, collect a single sample from within the 10 mixed samples
- Submit the single sample to the laboratory
The laboratory results usually will provide some recommendations for how the feedstuff can be used. There is an old saying, “Dilution is the solution …” meaning in this consideration, that many feedstuffs that contain higher levels of mycotoxin than would be acceptable, might be usable if a sufficient amount of non-mycotoxin contaminated feedstuff is used to dilute the mycotoxin. Your UNL Extension Educator, nutritionist or veterinarian can help evaluate the possible uses of a damaged feedstuff containing unacceptable levels of a mycotoxin.