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JenREES 4/16/23
The April 12, 2023 Nebraska Drought Monitor shows 98% of Nebraska in moderate to exceptional drought (D1-D4). We will keep praying rain; it will rain again one day! There’s truly concern about the dry conditions due to lack of subsoil moisture. Those planting last week shared how conditions were changing with the winds making surface soil hard. A few colleagues and I put together the following info. about planting into dry conditions in CropWatch that I will share this week.
I didn’t talk about planting deeper last week, but for those asking, Bob Nielsen, emeritus professor at Purdue said corn can be seeded 2.5-3” deep if that’s where uniform soil moisture is located in order to achieve uniform germination and emergence. We don’t recommend planting soybean deeper than 2.5”.
In general, we would only suggest watering before planting if the planter needs higher soil moisture levels to work well. So, if the soil is too hard, too powdery or cloddy, it may be worth running the pivot. Another situation to consider pre-watering is if greater than 180 lb/ac anhydrous ammonia was applied in a strip with less than two inches of moisture received since application to help reduce ammonia burn to the corn. Otherwise, our recommendation is to run the pivot after you plant if needed.
The usual recommendation is not to run a pivot when temperatures are below 40 degrees. Last year, several pivots were operated below 40 degrees without problem, but keep in mind with low dewpoints the pivot can ice up when the actual air temperature is well above 32. So, if you do choose to run in these conditions, keep a close eye out for ice buildup, which can collapse the pivot.
Bare, powdery soils will seal over very easily from rain or irrigation, so keep an eye out for runoff problems even with fairly low application amounts. And make sure if you do irrigate that you put on enough to get water down to the moist soil below. This is particularly a problem with tillage or where fertilizer knives have been used and dried the soil out.
It’s important that herbicides are activated with 0.5- to 0.75-inch of rainfall or irrigation, preferentially within five to seven days after herbicide application. If moisture received is less than this amount, some herbicide products have the potential to remain on the soil for up to 14 days without being fully activated. We will have to see how the high winds blowing soil and removing soil particles containing herbicide impact future weed control.
For those who applied dry or liquid urea on the soil surface, particularly without the use of an inhibitor, irrigation of 0.5-inch can help with incorporating the urea into the soil and minimize urea loss. If irrigation is not available, an inhibitor was not used and no rainfall has been received within seven days, monitor the corn crop to determine if nitrogen deficiency occurs due to nitrogen loss.
John Mick, Pioneer agronomist, shared last year that water from irrigation wells in the southern part of the state often is around 50-53°F, with it slightly less in temperature as one moves north in the state. These temperatures are not a problem to be concerned with regarding any negative impacts to seeds imbibing water.
Lawns: For those struggling with lawn winterkill, Kelly Feehan shares, “Some lawns may come out of winter with dead areas in need of reseeding. While early September is the ideal time to seed Kentucky bluegrass and tall fescue, spring seeding success can be improved by seeding as soon as possible so seedlings establish roots before summers’ heat. Improve seed to soil contact by aerifying, power raking, and/or hand raking right before seeding. After seeding, a light raking will further mix the seed and soil. Water lightly and often to keep the seedbed moist. Mulch will help conserve water, but use lightly so at least 30 to 40% of soil is still visible through the mulch. Use low rates of fertilizer, about one-half to three-fourths pounds per 1000 square feet, applied every four to six weeks until mid-June; and keep the area well-watered all summer while avoiding overwatering which can lead to poor rooting and disease.” Also avoid crabgrass preventer to newly seeded areas.
Evaluating Wheat Stands handout by Nathan Mueller: https://croptechcafe.org/wp-content/uploads/2020/04/Evaluating-Winter-Wheat-Stands.pdf
JenREES 4/25/22
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.
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