Bean harvest was rolling this week. Hearing non-irrigated beans in the area ranging from 40-60 bu/ac and irrigated beans going 70-90+. Regarding solar radiation and some wondering about smoke impact on drydown, I ran data from 9/1/20 though 9/26/20 for Harvard and York weather stations. Then looked at long term average for this same September time-frame from 1996-2020. Both stations showed slightly higher solar radiation in 2020 compared to the long-term average for September (York: 379 and 372 langleys respectively) (Harvard: 383 and 376 langleys respectively). And, it was higher yet for 2020 when I queried Sept. 10-26 for same time periods. So, unsure solar radiation was the factor impacting drydown for this part of the State?
Small Grains and Weed Control: Been watching weed control particularly in soybean fields. For future columns/winter programs, I’d like to hear from you. What weed control approaches have worked in your soybean and corn fields? I’m curious about all systems and all types of weed control options. Please share at firstname.lastname@example.org or give me a call at the Extension Office. Thanks!
In the past, I’ve shared weed control begins at harvest by not combining patches of weeds or endrows full of weeds. I realize that’s difficult to do, and for many fields, we’re past this point. From a system’s perspective, another option to aid weed control is to plant a small grain such as wheat, rye or triticale this fall. We had a whole edition of CropWatch devoted to wheat production here: https://cropwatch.unl.edu/2020/september-4-2020. Wheat provides an option for both grazing and grain. Rye provides the best option for earliest green-up/growth in the spring and longest seeding time as it can be seeded into December. Triticale provides the most biomass but produces the latest into late May/early June. All keep the ground covered from light interception penetrating the soil surface which allows weed seeds to germinate. While I’ve observed this in farmers’ fields, there’s also recent research from K-State that supports the impact of a small grain in rotation for weed control.
One study looked at marestail (horseweed) and palmer amaranth control from 2014-2015 in no-till soybeans at six locations in eastern Kansas. They also found the majority of marestail emerged in the fall (research from UNL showed up to 95% does). They compared five cover crop treatments including: no cover; fall-sown winter wheat; spring-sown oat; pea; and mixture of oat and pea. Cover crops were terminated in May with glyphosate and 2,4-D alone or with residual herbicides of flumioxazin + pyroxasulfone (Fierce). Ten weeks post-termination, palmer amaranth biomass was 98% less in winter wheat and 91% less in spring oat compared to no cover crop.
Another study in Manhattan from 2015-2016 compared fall-seeded rye; a residual tank-mix of glyphosate, dicamba, chlorimuron-ethyl, tribenuron-methyl, and AMS; and no fall application. Four spring treatments included no spring application or three herbicide tank mixes: glyphosate, dicamba, and AMS alone or with flumioxazin + pyroxasulfone (Fierce) as early preplant, or as split applied with 2/3 preplant and 1/3 at soybean planting. They found the fall rye completely suppressed marestail while fall herbicide suppressed biomass by 93% and density by 86% compared to no fall application. They also found rye to reduce total weed biomass (including palmer amaranth) by 97% or more across all spring applications. In both studies, soybean yields were best with the combination of cover crop + herbicides or the combination of fall + spring herbicides compared to no cover and no herbicides.
The way I think about this for conventional systems is that the use of a small grain in the system reduces the pressure on the chemicals for having to provide all the control. It also buys some time for chemical control, perhaps even removing one application (based on these studies, small grain delayed at least a month till 50% palmer germination). Economically, while there’s the expense of seeding and purchasing the small grain seed, what are the other economics to consider? What could the small grain provide by reducing an additional chemical application, adding a forage crop after harvest, selling seed (if there’s a market), selling straw (depending on location for moisture savings & ability to get a cover back in for weed control), etc.? Just some considerations this fall looking at weed control by adding a small grain.
Crop Updates: It’s been interesting seeing growers sharing pics comparing crops on the same dates in 2018 to 2019. They are behind in many cases compared to last year. Yet, we can be thankful for every field that we’ve been able to plant in Nebraska this year! Weed control is something on many minds right now. On corn, please be sure to count collars to determine growth stages. First leaves are sloughing off on V5-V7 plants right now, so slitting open stalks to aid in counting collars is important as we think of herbicide applications. Bob Nielsen from Purdue has a nice recent article with photos to help you with this: http://www.kingcorn.org/news/timeless/VStageMethods.html. When it comes to beans, I’m concerned how much longer the PRE’s will hold. I share this every year in pesticide training to have the POST with residual on a week before you think you need it, even if you don’t see weeds in the field yet. So assess each field as to when your PRE went on, current weed emergence, and plan on your POST a week earlier to overlap when your PRE residual should be running out. Also, with palmer amaranth on people’s minds, consider attending a glyphosate resistant palmer amaranth field day July 10th near Carleton, NE. Dr. Jason Norsworthy from the University of Arkansas will be the featured speaker. For those who’ve heard me speak on palmer or at my pesticide trainings, much of what I share has been what I’ve learned from his presentations and research papers. You can learn more and register at: http://agronomy.unl.edu/palmer. Adding a small grain and diversifying our cropping systems is one way to aid in palmer/waterhemp management. There are several upcoming wheat and pulse crop field days occurring throughout Nebraska in the next two weeks and you can read more about them at: https://go.unl.edu/b65e.
At some point, irrigation may be needed again. Installing irrigation scheduling equipment now allows you to watch your soil moisture profile as your crops grow, gain better confidence in your readings, and it’s just easier to install them at earlier growth stages when there’s moisture in the profile. Here’s some tips for those using watermark sensors. (As I walk through this, I’m using kilopascals (kpa) for the sensor readings but the same numbers apply to centibars (cb)). First, be sure to prime the sensors to ensure they’re working correctly. Do this by soaking the sensors for at least 24 hours in water. If you still have mud on the sensors, gently remove with your fingers, not with a brush. Then check the readings to ensure they read 10 or less. If they don’t, I allow them to soak another 24 hours and recheck; replace any that don’t read 10 kpa or less. Allow the sensors to dry out to 199 kpa again by setting out in the sun/wind/blowing fans. (Note that water will move into the PVC tube during soaking, so you’ll need to remove the cap and dump the water out if you don’t have a hole drilled at the bottom of the PVC tube. This is also true during the installation process.) When you’re ready to install the sensors, they need to be soaked again, but it should only take them 1-5 minutes to read 10 kpa or less prior to installation. There’s a couple things I’ve learned with installations that help me. First, use an ag consultant’s tube on soil probe to dig the foot wherever the sensor is installed. This allows for a better fit with no air gaps along the sensor. I use a regular soil tube to dig the hole the foot/feet above that to aid in pushing the sensors. In wet, clayey soils, it can be difficult to push the PVC pipe into the ground, so digging the upper holes with a bigger tube helps me with that. The other thing I do is carry my bucket with water for the sensors to the field with me with the sensors. To aid with pushing the sensors in the ground, I wet the PVC tube with water from the bucket prior to installing it. NEVER pour water into the holes and don’t make a slurry mix. I’m hearing several were taught to do this, but it’s not what Nebraska Extension teaches based on Dr. Suat Irmak’s research as it will change the soil moisture of the holes compared to the surrounding soils. Make sure the sensors hit the bottom of the hole and fill in soil where the PVC pipe meets the soil line. Suat shared how he used rubber washers around the top of the PVC pipe at the soil line to aid in water not running down the PVC tube when soil cracks at the surface. For those installing ET gages, a reminder to remove the stopper from the ceramic top and fill the ceramic top with distilled water in addition to the main tube of the ET gage. I fill the ceramic top, allow it to soak into the ceramic plate a little and refill it. Then prime the inner tube with stopper ensuring there’s no air bubbles in the small tube after placing it into the ceramic top. You can also double check for air bubbles by gently removing the glass site gage (by pressing down on the rubber tubing at the base of the site gage), allowing some water to cycle through, and then replacing it.
Maple seedlings: Maple trees have now leafed out and the rain has allowed the abundance of seeds to produce seedlings in people’s lawns and gardens. I know they look bad because they do at my place too. Mowing is the best way to take care of them in your lawn and it will take several mowings to do so. Don’t lower your mowing height as you want to maintain a healthy grass canopy. Eventually the seedlings will continue to grow to where the mower blade cuts off below the growing point and the seedlings will die. In the flower beds, they are very easy to pull right now. It takes some extra time, but that’s the best way to rid them there.
Last week I had the opportunity to attend and speak at the Weed Science School. It was an interesting day of learning, discussion, even reflection. Dr. Amit Jhala, Weed Science Specialist, did a really nice job of organizing the day and creating opportunities to hear from University, Industry, and Nebraska Dept. of Ag (NDA) speakers in addition to providing hands-on activities. While dicamba was a topic that was discussed, we didn’t hear about EPA’s ruling till the following day that the RUP products for soybean will be re-registered. Tim Creger with NDA shared that 6 other dicamba products, most with pre-mixes, will be registered this year. He also shared there are 40 ag labeled dicamba products that are not restricted use pesticides, and as long as they aren’t registered for soybean use, he doesn’t anticipate they will become restricted use pesticides. Comparing NDA claims from 2017 to 2018, they received 95 claims (24 investigated due to lack of resources) in 2017 compared to 106 (50 investigated but only 31 resulted in full investigations due to desire of the person filing the complaint) in 2018. Of the 106 claims in 2018, 17 were non-ag related.
In last week’s column, in sharing about fall burndown apps, I had mentioned that 60% ofmarestail (horseweed) in Nebraska germinated in the fall. An updated number of 90-95% fall germination for Eastern Nebraska was shared. This once again emphasizes the importance of considering fall apps for fields with marestail pressure.
Dr. Kevin Bradley from University of Missouri shared on 7 points he’s learned from 15 years of researching waterhemp. They included: Never underestimate waterhemp (I’d say the same for palmer); Era of simple, convenient, quick control is over; Use full herbicide rates and pre-emergence herbicides with residual; Overlap pre + post applications (which we also see with palmer-put that post on a week earlier than you think you need it); Glufosinate, dicamba, and 2,4-D may work now but they’re tools being abused; New traits won’t solve the problem; and Get rid of herbicide-centric way of thinking-we need an integrated approach. He thought he was sharing something shocking in that last statement, but I’d say several of us seek an integrated system’s approach to what we do, including weed management. So ultimately, herbicides aren’t the answer for weed control and we need to be thinking about management from a system’s perspective including crop rotation, use of cover crops, residue management, seed destruction, etc. Especially as from the industry perspective presented, it takes an average of 12 years and average investment of $250 million for a new chemistry to be developed. They are seeking chemistries now that work on specific sites of action (how targets within plant) within the mode of action (specific group or chemistry number).
On November 14th, we’re hosting a Farm/Ranch Transition workshop at the 4-H building in York. This is the closest location for our area. The workshop will focus on the needs of the “sandwich generation” between parents who still own land and children who might want to join the operation, on whom farm/ranch transition and transfer often falls. The Gen2, or Sandwich Generation, will learn how to communicate with family to understand the transition and practice asking difficult questions. Legal topics will include elements of a good business entity, levels of layers for on-farm heirs control and access, and turning agreements into effective written leases. Joe Hawbaker, estate planning attorney, and Allan Vyhnalek, Nebraska Extension transition specialist, will share stories and experiences to successfully plan on the legal side. Dave Goeller, financial and transition specialist, will cover financial considerations, retirement, and compensation versus contribution. Cost is $20 per person. If more than two people are attending per operation, the cost is $15/person. Pre-register at (402) 362-5508 or email@example.com for meal count. Funding for this project was provided by the North Central Extension Risk Management Education Center, the USDA National Institute of Food and Agriculture Award Number 2015-49200-24226.
November 15th is the York County Corn Grower Banquet at Chances ‘R in York. Social time begins at 6:30 p.m. with a wonderful meal at 7:00 p.m. We will hear from Nate Blum, LEAD 36, on his international trip. We will also hear from local and state directors. Tickets are only $10 and can be obtained from any of the local Corn Grower directors or from the Extension Office at (402) 362-5508. The winner of the Yeti cooler from guessing plot yields will be announced, and those who guessed need to be present in order to have a chance to win. Plot results can be obtained from the Extension Office. Hope to see you there for a nice evening with a wonderful meal to hopefully celebrate the end of harvest season!
In the landscape, October is the month to water, control weeds, and plant bulbs, trees and shrubs. It is also the month to wait until after a freeze to cut back perennial plants and wait for the soil to freeze before covering tender plants with winter mulch. Kelly Feehan, UNL Extension Educator, provides the following information.
Sometimes people ask if trees and shrubs should be watered at this time of year since their leaves will soon drop off; and how late in the season lawns should be watered. As long as the soil is dry, go ahead and water. Plant roots continue to grow long after leaves drop off trees and shrubs and after grass stops growing. Roots, rhizomes and stolons can grow well into November and fall watering promotes this growth helping plants recover from summer stresses. Plant energy can be used for root growth during fall since energy is no longer needed for leaves, flowering or seed production. Roots continue to grow until soil temperatures drop below 40 degrees Fahrenheit with available moisture.
Water enough to moisten the soil to a depth of about eight to twelve inches for trees and shrubs and six inches for lawns. Keep in mind that a lack of oxygen due to a saturated soil is just as damaging to roots as a lack of water. Allow the soil to dry between watering.
Because roots continue to grow well into fall, September through October is a good time to plant deciduous trees and shrubs. For spring flowering bulbs, wait until soil temperatures drop to 60 degrees Fahrenheit to plant.
A common question asked about fall planting is if a starter fertilizer needs to be used at planting time. Starter fertilizers are high in phosphorous, a nutrient important to root production. The only way to know the answer to this question is to have a soil test taken. However, most landscape soils are high in phosphorous (P). Fall soils are often warm and dry which makes P more readily available. In most cases a starter fertilizer does not need to be used during fall planting.
More important is to plant at the correct depth. With bulbs, follow label directions for planting depth. It varies depending on bulb size. Some recommendations say to plant about one to two inches deeper than recommended. The opposite is true for trees and shrubs. Before planting trees, locate where the trunk flares out at the trunk base then plant at a depth so the flare is visible above ground. Do not loosen the soil beneath the root ball or the tree may settle and end up planted too deep. In heavier clay soils plant so the trunk taper is one to two inches above the ground.
October is the best time to control perennial broadleaf weeds like dandelions, ground ivy and clover. There is no ideal time during fall to apply lawn weed and feed products together. The best time to fall fertilize lawns is in early September and again in late October or early November. The best time to apply herbicides for lawn weeds is about mid-October before a hard freeze.
Weed control can be more effective and less herbicide will be applied where it is not needed by avoiding the use of combined weed and feed products during fall. One can achieve better weed coverage and control of established broadleaf weeds if the weeds are spot treated, typically with a liquid formulation of herbicide.
Here’s wishing you a great October of accomplishing landscaping projects!