Signs of spring are all around with tulips and flowering shrubs budding or beginning to break forth in blossom! Have heard of a range of planting conditions and received a variety of questions last week. The following are some considerations as you begin planting or continue to plant this year. Also, John Mick, Pioneer Hi-Bred field agronomist, had excellent planter setting and planting season tips in his agronomy newsletter this week and a team of us share more detail in this CropWatch article.
Honestly, for many of us as agronomists, this spring is a new territory. We’ve dealt with dry conditions and wet ones before, but this situation of not receiving rains, the high winds, and availability of products presents a new challenge for many of us. There’s the saying ‘plant in the dust and your bins will bust’, but there’s also difficulty surrounding herbicide activation and potential ammonia burn from fall/spring applied anhydrous in the seed row.
Soil temps, depth, pops, conditions: We have one chance with planting to start the season off right, so soil conditions fit for planting, seeding depth for corn and soybeans close to 2”, and soil temps in the mid-40’s on a warming trend with no chance of a cold snap within 8-24 hours for soybean and 48 hours for corn are important components to achieving this. I prefer removing one more stress off corn by putting it in the ground when temps will stay over 50F for 5-7 days. It’s been interesting to see the shift in the number of soybean acres planted before corn in the several county area this year. I’m hearing the need for very high down force and difficulty getting planters in the ground, particularly down in the Nuckolls, Webster, Clay, Adams-county areas. Some have shared that no-till ground is working amazing and others have shared the wind removing residue has made the ground extra hard.
Finding moisture has been of concern to both non-irrigated and irrigated farmers as the winds continue. Bob Nielsen at Purdue shared that corn can be planted 3-4” deep based on their research. I wouldn’t put soybean past 2.5”. Regarding seeding rates, I haven’t recommended changing them unless the soybean germination percentage is less than 85%. We do have growers conducting soybean seeding rate studies again this year, and if you’re interested in trying that as well, please let me know.
Some have wondered about planting non-irrigated crops or waiting for a rain. This ultimately will be a grower by grower and field by field decision. We’re only setting at April 25th as I write this and as we think of planting windows vs. planting dates, we are still setting good. Many have asked about watering prior to planting. In general, we’re not recommending it at this time; if we don’t get rains as this planting season continues, we may need to adjust that thinking. Ultimately, we’d say to water before planting if the ground isn’t fit due to extra cloddy or hard soils. For those who applied anhydrous via strip till whether fall or spring, watering prior to planting may help with ammonia burn damage to the seed and to the plant when the roots reach the application zone.
I’ve also been asked about pre-plant herbicides. With the colder soil temps, several have mentioned not seeing weeds thus far. I’m concerned about a few things regarding PREs. One, activation. Most need at least 0.5-0.75” of moisture 5-7 days after application. Some can last on the ground up to 14 days with partial activation. With the wind, my concern is soil particles containing herbicide not staying on the soil surface (depending on tillage practice). Another concern is the moisture levels in soybean fields, planting depth, and PPO-inhibiting herbicides. This is a great chemistry. The challenge can be damage to seeds and seedlings can occur if they come in contact with the herbicide by the seed vee not closing, seed trench cracking, or rain/water-splash onto hypocotyls and cotyledons. Planting soybeans deeper, at least 1.5” (UNL research found best yield at 1.75”), will help allow the soybean to imbibe water from soils that have moisture at that depth. By planting shallow into dry soil, applying herbicide and then having rain or irrigation activate the herbicide, the herbicide can potentially enter the seed when completing the water-uptake process, damaging it. For those concerned about these different situations with pre-plant herbicides, an alternative could be to use a Group 15 product once the corn or soybean emerges. Just know those products won’t kill any weeds that have emerged but will provide residual for ones that come later.
Reminder of York Co. Tire Collection April 30 and May 1 at the York Co. Landfill from 8 a.m.-5 p.m. No tires on rims and participants must show proof of residency. More info: 402-363-2690.
Happy Easter! This will truly be one to remember and hope you were able to still connect with family and friends in some way. For fruit trees and freeze temp. thresholds, please check out this resource: https://www.canr.msu.edu/uploads/files/PictureTableofFruitFreezeDamageThresholds.pdf. With planting having started for some or anticipated in the next few weeks, wanted to share some things I’ve been thinking about and some questions I’ve received.
As much as we have more physical distance in ag, it may be wise to have some plans in place in the event someone becomes sick with COVID-19 in your crop or livestock operation. Things such as disinfecting equipment and a sample 0-2 month plan with contact phone numbers are available in this week’s CropWatch at cropwatch.unl.edu. There’s also information on the CARES Act explaining the numbers. A series of Farm/Ranch COVID-19 free economic webinars are upcoming from UNL AgEcon. The first is this Thurs. April 16th at 3 p.m. CST. and features Nathan Kauffman, with the Federal Reserve Bank of Kansas City, presenting on COVID-19 Economic Developments and U.S. Agriculture. Details and recordings will be posted at https://go.unl.edu/manage2020.
Planting Considerations: It was nice to see equipment out in fields this past week! With tight economics, it’s important to make wise decisions with the factors we can control during planting season; it sets the stage for the rest of the year. One factor to consider is planting windows instead of planting dates. While this week is mid-April, it may not provide the best opportunities for planting. Be sure to check soil temps and plant at proper depth, not mudding in seed, and plant as close to 50F soil temps as possible when there’s a warming trend. Avoid planting when there’s potential for a cold rain/cold snap within 48 hours for corn and at least 24 hours for soybean. It’s also best to get seed in the ground 1.5-2” deep. For corn, this is critical in helping with nodal root establishment. For soybean, this aids in buffered soil moisture and temperature and helps delay emergence to aid against potential frost. Numerous research studies have proven the yield benefit to early planted soybean. Outside of the genetics, it’s the top way to improve soybean yields. When we conducted these studies via on-farm research, we also had planting date X planting rate studies. Those studies showed no yield difference when planting 120K vs. 180K in April vs. May beans. All the planting date studies had an insecticide + fungicide seed treatment and I have no data without it. Our soybean planting rate studies did not always have a seed treatment and now 13 years of that data still shows 90-120K planted seeds being the most economical while 120K is what we’d recommend for yield.
In this week’s CropWatch, I wrote an article with Jim Specht on soybean germination. The imbibition phase (water uptake) is the critical phase for potential seed chilling. Once the imbibition phase is complete, the soybean going through the osmotic phase can tolerate 35-40F soil temps as long as soil is not saturated. The reason why we say at least 24 hours for soybean vs. 48 hours for corn (regarding cold snap/cold rain) is because the soybean seed imbibes water much faster than corn. You can prove this to yourself! Put a soybean seed and corn seed in water and watch what happens. When teaching youth ag literacy, I put soybean seeds in water to show them the seed coat, root and first leaves. Granted, we’re not planting soybean into water, but it helps one see the difference in how the seeds imbibe water. Studies from journal articles showed the imbibition phase could complete in as little as 8-12 hours. However, it all depends on the beginning soil moisture, soil temperature, quality of the seed (no nicks in the seed coat, free of wrinkles from wet/dry cycles, higher seed moisture of 13-16%). There have also been experiments to suggest that soybean can be planted in 45F soil temps if soil moisture is stable and no cold rains occur during the imbibition period.
I’ve also received a few questions regarding rye rapidly growing and what to do. I have no research-only observation and talking to others. I’m still a fan of planting green. However, have noticed difficulty with residual herbicides applied to tall rye (above 12”) and getting down to the soil, thus weed escapes. So, a few thoughts. If you’re concerned about the rye, you can always terminate a few weeks before planting. Otherwise, consider splitting your residual with half on when you kill rye after planting with other half later or putting on your residual in a second pass after killing rye. Would welcome others’ thoughts/experiences of what’s working for you!
Dicamba Webinar: The National Ag Law Center is hosting a free webinar titled ‘The Deal with Dicamba: An Overview of Dicamba-Related Litigation’ on April 15th at 11 a.m. CST. It will discuss various lawsuits filed in response to crop damage allegedly caused by herbicides containing dicamba. Details: https://bit.ly/3e2LvGX.
Perhaps it was the hard winter, but I’m finding the flowering trees to be exceptionally pretty this year! Corn and even some soybean went into the ground this past week too. In last week’s column I shared regarding planting considerations yet would still encourage growers to keep considering your local field conditions before planting. You’re hearing some of these same things from both Extension and Industry partners and we realize field situations differ. We keep repeating these things to provide reassurance when you’re questioning decisions. We’ve already seen problems with anhydrous application in too wet of conditions in some fields. We’ve already seen some situations that were too wet when corn was planted leading to problems with compaction, depth issues, and not closing seed vee’s. With the cold snap, it’s important to consider soil temperatures (preferably around 50F or warmer for next 48 hours), soil moisture conditions, air temperatures for the next 48 hours, potential for cold rain, and cold tolerance of seed. Soil temperatures are listed at http://go.unl.edu/soiltemp and I would also encourage you to check your own particular field conditions. Last week, I was finding soil temperatures in local field conditions to be cooler than what was being reported from high plains regional climate center. If you don’t have a soil temperature thermometer, you can do this with a meat thermometer (and just dedicate it for field use).
I can appreciate the added concern and stress with this week’s forecast. There’s several planting-related articles in this week’s CropWatch at http://cropwatch.unl.edu. Two really helpful articles from Roger Elmore share on corn planting windows where he used USDA NASS data to show Nebraska data and also shared how other states throughout the Corn Belt have found similar results regarding planting windows. The key point is there’s a planting window between mid-April to mid-May within which optimum yields are usually obtained. After this period, yields decrease rapidly. So there’s still time and the planting conditions play a role in determining final yield by getting that seed off to a good start. You also keep hearing me talk about planting soybean early. Even as early as you can in May is better than mid to late May for higher yields if that works for your situation.
Browning Evergreen Trees and Shrubs: This past winter was hard on many things. When it comes to evergreen trees, the deep frost line and extreme cold led to the inability for transpiring trees to uptake moisture. This resulted in needles appearing brown and looking dead, particularly on the north and sometimes west sides of trees. I’m seeing this particularly on junipers, cedars, arborvitae, white pines, and some spruce. We’d recommend waiting till June before pruning any dead portions out or removing any trees/shrubs to see what happens with new growth.
Rhizosphaera Needle Cast in Spruce has been really bad the past few years. If you’re seeing spruce needles on lower parts of the tree turning yellow/reddish-purple/brown, then this disease may be the problem. The fungus continues moving upward on the tree. Affected needles are prematurely cast from the tree. Above average moisture during the growing season in parts of the State led to an increasing number of spruces affected by the Rhizosphaera fungus. What’s interesting is that the fungus infects the needles in spring but the symptoms often don’t appear till the following spring. One way to double check is to look for tiny black specks on the needles and on the twigs. The good news is that fungicide applications of chlorothalonil (Fungonil, Daconil, Bravo) or Bordeaux mixture in May can help when shoots are ½ to 2” in length! If we get frequent rains this growing season, applications can be repeated every 3-4 weeks.
Vegetable Planting Guide: Gary Zoubek had put together an excellent vegetable planting guide for the area which can be obtained at the Extension Office or at: https://go.unl.edu/d7qk.
Spring Lawn Seedings: With the difficulty of this past year, many didn’t get dormant seedings on because of all the snow and typically lawn renovation in the spring is difficult because of the inability for applying crabgrass preventer to newly seeded areas. However, a new product has changed this! Scott’s Turf Builder Starter Food for New Grass contains mesotrione which provides PRE and POST control of weeds without affecting the new bluegrass or fescue seeding. We’d still recommending seeding as soon as possible or else wait till August. Tenacity is also a product containing mesotrione that works as a POST for emerged crabgrass, foxtail, and for those dealing with nimblewill (best to apply on troublesome grassy weeds up to 1” tall).
Rhubarb and Frost: For those impacted by frost/freeze this past weekend, if rhubarb leaves are not damaged too much and the stalks remain firm, it is still safe to eat. If the leaves are severely damaged or the stalks become soft or mushy, do not eat these stalks. Remove and discard them. New stalks can be harvested and eaten. Rhubarb often develops seedheads following cold temperatures, but this also does not affect eating quality of the stalks. Remove rhubarb seedheads and discard.
Planting Considerations: Everything we do at planting sets the stage for the rest of the year. We’re blessed to have equipment that can allow for many acres to be planted in a short amount of time. And, we have the ability to mess up a lot of acres in a short amount of time.
For soil conditions, it’s important that we’re not mudding in fertilizer and seed to avoid compaction and uneven emergence issues. Soil temperature information can be found at: https://go.unl.edu/soiltemp. It’s best to plant when soil temps are as close to 50°F as possible, check weather conditions for next 48 hours to hopefully maintain temps 50°F or higher, and avoid saturated soil conditions. If planting a few degrees less than 50°F, make sure to check with seed dealers on more cold-tolerant seed and only do so if the forecast is calling for warm temperatures the next few days that would also help increase soil temperatures. Once planted, corn seeds need a 48-hour window and soybeans need a 24-hour window when the soil temperature at planting depth does not drop much below 50°F. Otherwise chilling injury is possible.
With the variability of weather each spring, we perhaps need to shift our focus from “calendar dates” to “planting windows”. The optimum planting date for corn may not be in April every year. Research from Iowa State found optimum planting date windows to obtain at least 98% yield potential range from April 15-May 9 for northwest and central Iowa; from April 17 to May 8 for southwest Iowa; and from April 12-30 for north central and northeast Iowa. To achieve at least 95% yield potential, those ranges extend from April 15 to May 18 for northwest and central Iowa; from April 12 to May 13 for southwest and southeast Iowa; and from April 12 to May 5 for north central and northeast Iowa. It’s not Nebraska data, but could be considerations for us for similar areas of Nebraska. And, while we don’t have a lot of data in Nebraska, one can use USDA ag statistic yields and I’ve also used the Hybrid Maize Model to show how yearly weather can impact optimum planting windows for best potential yield.
Planting soybean early is critical to maximizing yield. Beyond genetics, this is the primary way to increase soybean yield through numerous University studies in addition to grower-reported data. Because of this, an increasing number of growers are planting soybean earlier than corn or at least at the same time as planting corn. ‘Early’ is within reason, though. While we’ve had on-farm research fields and many growers’ fields planted from April 22 and after (in good field conditions), be aware that crop insurance date is April 25. We also recommend adding an insecticide + fungicide seed treatment when planting in April as we have no data without seed treatment in our planting date studies.
Planting depth is also key. Aim to get corn and soybean in the ground 1.5-2” deep. This is critical for correct root establishment in corn to avoid rootless corn syndrome. While not as critical regarding root establishment for soybean, our UNL research showed lowest yields when soybean was planted 1.25” or less or 2.25” or greater with the highest yield at 1.75” deep. This is most likely because moisture and temperature were buffered, particularly when soybean was planted early. It’s important to get out and check seeding depth for all planter units within every field. Even with monitors showing down force and seeding depth, it’s still important to check. I’ve seen how adjusting down force can lift up planter ends resulting in shallow planting in the outside rows, particularly with center-fill planters. Results of improper/uneven planting depth can be seen all season long and may affect yields. While this takes time, you’ll be glad you caught any issues before too many acres are planted incorrectly!
For corn seeding rates, it’s best to check with your local seed dealer as all our research shows that optimal corn population varies by hybrid. However for soybean, our recommendation after 12 years of combined on-farm research studies continues to be: plant 120,000 seeds/acre, aim for a final plant stand of 100,000 plants/acre and you’ll save a little over $10/acre without reducing yields. If that’s too scary, try reducing your populations to 140,000 seeds/acre or try testing it for yourself via on-farm research! Please contact me if you’re interested in that. We have an article on our soybean seeding rate data in this week’s CropWatch at http://cropwatch.unl.edu.
Lawn Crabgrass Preventer and Fertilizer Application: Crabgrass is a warm season grass and needs soil temperatures to reach 55 degrees F for a few consecutive days to germinate. It doesn’t all germinate at once, thus the potential for a second flush in the summer. The targeted window to apply pre-emergence herbicides for crabgrass in eastern Nebraska is April 20 to May 5. Keep in mind that the product needs to move into the soil within 3 days or it will start breaking down due to sunlight exposure. You may also consider applying your crabgrass preventer with first lawn fertilizer application around the beginning of May.