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JenREESources 11/8/21

Nitrates and Grazing Forages: the fact that we haven’t had a hard frost is throwing a wrench into grazing covers. For those with cattle on cover crops, please be aware of the potential for nitrate and/or prussic acid poisoning with the light frosts. Nitrogen moves from the roots up the plant. When a frost occurs, nitrates accumulate in the plant, and, we had lighter frosts for several days in a row. For sorghum species where prussic acid poisoning is also of concern, we say to wait at least 5 days before returning animals back to the field after frost. And, for every light frost, the 5 day window resets until a hard freeze occurs (at 26F or lower). It’s been hard to find any recommendations regarding nitrate accumulations in brassicas after frost…and what happens to the nitrates after a frost. We know weathering in general reduces nitrate levels in plants by spring. Just advising to watch cattle with these light frosts-especially those in seed corn fields that had milo in corners.

A study conducted by Mary Lenz, grad student for Dr. Mary Drewnoski, found brassicas accumulate more nitrate than small grains, millet, sorghum/sudan grasses, or cover crop mixes, and that 48% of the brassica samples submitted to Ward Labs were considered “highly toxic” for nitrate levels compared to 20-28% of other cover crop species. Yet what’s interesting is how often fields in the “highly toxic” level (or with no testing) are grazed with no impacts. Dr. Mary Drewnoski has shared that brassicas and immature grasses are also high in energy and that cattle consuming diets high in energy can handle more nitrates. So, this may be why we thankfully don’t see more issues grazing turnips and radishes high in nitrate. She shared other factors for consideration are that cattle are selective and will graze the upper-most parts of plants first which are lower in nitrates, grazing animals eat more gradually than those receiving hay, and the high moisture forages that are grazed release nitrates at a slower rate than with dry forages like hay. Ways to reduce nitrate concerns when grazing include: turning out cattle full before grazing the covers, using lower risk cattle such as open cows and stockers (as pregnant cows have risk of abortion when fed forages high in nitrate), graze lowest nitrate fields first for adaptation, graze highest nitrate concentration fields lighter so not as much forage is removed, or there’s also the option of not grazing fields that are very high in nitrates.

Corn Nitrogen Calculator: For those desirous to calculate N rates utilizing different sources and prices, the UNL nitrogen calculator has been updated. Before, it didn’t allow for the prices we currently are experiencing and there’s been some updates to the manure credits. The UNL nitrogen equation itself has remained the same, and honestly, I still say it’s conservative. For example, the nitrogen credit from soybeans is 45 lbs/ac in the equation. However, on-farm research conducted in the mid-2000’s in this part of the State found a credit of 1 lb for every bushel up to 60 bu/ac was achievable in irrigated soybean.

To utilize the N calculator, go to: https://cropwatch.unl.edu/soils, scroll down to “Corn Nitrogen Recommendations Calculator” and download the excel spreadsheet. You will want to open the “October 2021” version. They’re currently working on an online calculator for the future.

A few questions I received this week: “How much yield loss should I expect if I reduce N rates?” and “With higher corn prices, how much profit is one giving up with lower yields due to lower N application?”. These are valid questions and ones every operation will have to determine for oneself. That’s where on-farm research is really helpful too.

We have lots of data through the years of comparing a grower base rate +/- 30 lbs. of nitrogen mostly showing no yield differences. Most of this data is from the 1990’s for this part of the State, with data from the past 10 years from other parts of the State. In 2020 and 2021, a grower conducted nitrogen rate studies in York and Hamilton counties using his rate +/- 50 lb N. As I’ve shared the results with growers with the above-mentioned questions, they’ve been surprised at the yields and profits. I’ve summarized the grower’s results at jenreesources.com and also showed the profit based on today’s fertilizer prices. There’s a few ways to approach this data. It shows minimal benefit to yield and profit for increasing nitrogen application above the grower’s rate. Thus, there may be opportunity this year for those who have been over-fertilizing for high yield goals to try cutting back. It also shows that yield is reduced to some extent by reducing N rate 50 lb/ac below what the grower’s rate typically would be; however, with today’s prices, profit may be comparable. We also have several farmers who are already doing a great job with fertilizer rate for their realistic yield goals, so there may not be room to cut back. Appreciate all the farmers conducting on-farm research so we have data to share to help in answering questions!


*Please overlook my formatting issues below. There are no links even though some of the wording keeps appearing in blue instead of black.

2020 York County Spring Anhydrous Nitrogen Rate on Corn
This study essentially showed what the previous studies had: that less nitrogen can be applied without hurting yield or net return. 50 lb/ac N above the grower rate resulted in reduced profit. Field yields were impacted by the July 9, 2020 wind storm. This study is sponsored in part by the UBBNRD.

Pre-PlantIn-seasonlbs N/bu grainYieldMarginal Net Return
110 lb N/ac spring NH3 (March)25 lb N/ac as UAN May0.73 C184 A$599.14 A ($849.30)
160 lb N/ac spring NH3 (March)25 lb N/ac as UAN May0.98 B189 A$600.38 A ($837.80)
210 lb N/ac spring NH3 (March)25 lb N/ac as UAN May1.23 A191 A$594.88 A ($810.70)

*Values with the same letter are not statistically different at a 90% confidence level. Marginal net return based on $3.51/bu corn, $8/ac for the anhydrous application cost, $0.28/lb N as anhydrous, and $0.35/lb N as UAN. (Updated marginal net return using $5.20/bu corn, $0.75/lb N as anhydrous and $1/lb N as UAN.)


2020 Hamilton County Evaluating Nitrogen Rate and Timing on Corn
This study showed no difference in nitrogen timing nor rate on yield and showed less nitrogen can be applied without impacting yield. Yields were impacted by the July 9, 2020 windstorm. This study is sponsored in part by the UBBNRD.

Pre-PlantIn-seasonlbs N/bu grainYieldMarginal Net Return
180 lb N/ac Fall NH325 lb N/ac as UAN May1.03 B199 A$629.85 A ($866.80)
230 lb N/ac Fall NH325 lb N/ac as UAN May1.27 A201 A$625.49 A ($839.70)
180 lb N/ac Spring NH325 lb N/ac as UAN May1.02 B201 A$638.30 A ($877.20)
230 lb N/ac Spring NH325 lb N/ac as UAN May1.24 A206 A$641.70 A ($865.70)
120 lb/ac N Spring NH325 lb N/ac as UAN May
60 lb N/ac side-dress V8
1.00 B205 A$645.69 A ($880.00)
170 lb/ac N Spring NH325 lb N/ac as UAN May
60 lb N/ac side-dress V8
1.24 A206 A$633.50 A ($847.70)

Values with the same letter are not significantly different at a 90% confidence level. Marginal net return based on $3.51 bu corn, $0.28/lb N as anhydrous ammonia, $8.00/ac for anhydrous application, $0.35/lb for UAN applied with herbicide or as a sidedress, and $3/ac for sidedress UAN application. (Updated marginal net return using $5.20/bu corn, $0.75/lb N as anhydrous, $8/ac for anhydrous application, $1/lb for UAN applied with herbicide or as sidedress, and $3/ac for sidedress UAN application.)


2021 Hamilton County Spring Anhydrous N Rate Study

20% wind damage from July 9, 2021 storm. Updated marginal net return using $5.20/bu corn, $0.75/lb N as anhydrous shows essentially no difference in profit for any yield differences observed:

100 lb-N/ac: $1053.40
150 lb-N/ac: $1052.30
200 lb-N/ac: $1051.20


2021 York County Spring Anhydrous N Rate Study

20% wind damage from July 9, 2021 storm. Updated marginal net return using $5.20/bu corn, $0.75/lb N as anhydrous:

130 lb-N/ac: $900.90
180 lb-N/ac: $969.10
230 lb-N/ac: $924.70



2021 York County Timing by N Rate Study

Spring 140 lb/ac: 110 lb/ac N as anhydrous and 30 lb/ac N with herbicide

Spring 190 lb/ac: 160 lb/ac N as anhydrous and 30 lb/ac N with herbicide

Split 140 lb/ac: 50 lb/ac N as anhydrous, 30 lb/ac N with herbicide, and 60 lb/ac N sidedressed at V8

Split 190 lb/ac: 100 lb/ac N as anhydrous, 30 lb/ac N with herbicide, and 60 lb/ac N sidedressed at V8

This study is sponsored in part by the UBBNRD. Updated marginal net return using $5.20/bu corn, $0.75/lb N as anhydrous, $1/lb N as UAN and $8/ac for the sidedress UAN application:
140 lb/ac spring: $1109.50
190 lb/ac spring: $1077.20
140 lb/ac split: $1096.90
190 lb/ac split: $1054.20

JenREES 10/17/21

The York County Corn Grower plot and several on-farm research studies were harvested this past week. Thank you to Ron and Brad Makovicka for planting, harvesting, and hosting the corn grower plot and to all the seed companies who participated! The plot averaged 277 bu/ac on 190 lbs N of fall applied anhydrous and 3 gal of starter. That’s a great nitrogen efficiency per bushel produced! You can view the results at jenreesources.com or can pick up a hard copy of the results at the York Co. Extension Office.

I also wish to thank all of the cooperators who participate in Nebraska Extension’s On-Farm Research Network, especially all of you who work with me! The farmers conducting studies in this part of the State account for nearly 1/3 of the studies being conducted state-wide! A number of previous years’ results in addition to this year are studies involving nitrogen management. I will share more specific study results in the future. For now, with nitrogen prices continuing to climb, sharing ideas for consideration to try on your farms.  

  • Nitrogen Timing: Fall vs. Spring Anhydrous OR Combination of pre-plant nitrogen plus in-season nitrogen. We have one continuous fall vs. spring applied anhydrous study in York Co. and I’ve summarized results of several split applied studies in the past. It’d be great to have more producers trying these types of studies.
  • Nitrogen Rate: 50 lbs N +/- grower rate. For example, consider: 100, 150, 200 lbs N/ac comparisons or 130, 180, 230 lbs N/ac comparisons. Growers doing these studies continue to find minimal yield gain for more N (less than 5 bu/ac for increasing 50 lbs N/ac). This year is a great one to try this for yourself with the high N prices.
  • Nitrogen product substitute: There’s a number of products that are in some way promoted for reducing nitrogen, either by the product using microbes to help “fix N” for corn or using microbes to make N more available. So, consider trying a product like those and reduce the nitrogen by a set rate (30-50 lbs/ac) vs. a control with full N rate without the product. We do have a few studies in 2021 with these products and will share those results this winter.
  • Reducing plant population under irrigated system using a strong flex hybrid. A handful of guys I know have tried this and have determined the population that gives them the best economic return for reduced nitrogen and water inputs. Some have also considered strong non-irrigated hybrids under pivots to reduce water and nitrogen inputs.
  • Planting another crop: I have heard several saying they plan to plant more soybeans. A number of growers have also increased interest in milo (grain sorghum) due to the lower inputs necessary.
  • For those who own land (perhaps easier with a pivot depending on where you are in the State) and have cattle, perhaps consider the economics of annual forages for your particular operation.
  • Growing nitrogen via interseeding cover crops or planting corn into terminated vetch or solid stand of red (or white?) clover. I realize this one is more outside of the box and there’s a lot of questions surrounding it. The past few years, especially 2021, provided opportunity for numerous observations and learning experiences from growers trying these things. I just need time to summarize and will share this winter.

I know most producers are trying things on your own on your farms. The above are just some additional ideas for consideration and an opportunity to try via on-farm research to obtain more data. I will share specific protocols next week. The data helps inform all of us on practices/products that are research-proven in Nebraska.

Tar Spot of corn was found in York County via a sample submitted by Jon Propheter last week. Nothing to worry about this season. It can be easily confused with southern rust teliospores this time of year. Will share more on management this winter.

(Phtotos below: left-hand photo is tar spot, one lesion, very low incidence. Doesn’t scrape off leaf. Right-hand photo is southern rust teliospores; you can see the raised pustules looking closely in the photo and can rub them off.)

BugFest 2021 is now open at https://go.unl.edu/bugfest2021 till Oct. 24!  There are videos about Nebraska Tiger Beetles, Wild Bees, Bed Bugs, Magical Creatures, How to Draw Insects, and much more.

Young, Beginning and Small Farmers Symposium November 8: Through a series of fast-paced panel discussions, participants will co-create innovative solutions regarding: Challenges facing young, beginning and small farming operations; Existing programs for financing young, beginning and small farmers; Innovative resource approaches for the farm of the future. This program will be held from 9 a.m.-4 p.m. (registration at 8:30 a.m.) at the Nebraska East Union on UNL East Campus in Lincoln. It will also be streamed live online. Those wishing to attend in person need to register and request a parking permit. There is no cost. Additional details at: https://go.unl.edu/hzcj.


JenREES 3/7/21

Farm Bill ARC-IC: Unless one has a field that tends to get hit with lower yields compared to county average every year, I’m unsure that ARC-IC is a fit for many farmers in this part of the State. For the 2021 decision, one would need to expect 2021 yield to be significantly less than county average yields. So if your field(s) are typically near or above county average yields, it’s perhaps not the wisest decision.

Lawn Care: The beautiful weather is a great opportunity to rake lawns, remove leaves from lawns, and dormant overseed grass in thin spots. Dormant seeding provides an opportunity for seed to grow when soil temperatures warm and spring rains come. Prepare areas to overseed by hand raking small areas to remove dead growth and loosen the soil surface. Large areas can be heavily aerated. It’s best to only power rake if there’s a thatch layer of ½” or more present. Overseed Kentucky bluegrass at 1-2 lbs/1000 square feet and tall fescue at 4-6 lbs/1000 square feet. Also, it’s too early to apply fertilizer and herbicides to lawns.

Solar Electric Questions: Will share more regarding a free webinar series next week to be held from Mar. 30-Apr. 8. If you have specific solar-related questions right now, please direct them to John Hay, Nebraska Extension Educator at 402-472-0408 or jhay2@unl.edu.

Nitrogen Rate and Timing Studies: An article written by Dr. Charlie Wortmann and colleagues shared, “Partial Factor Productivity (PFP) is commonly expressed as yield per unit input, e.g. bushels of corn per pound of fertilizer N applied (bu/lb N). PFP can be adapted to units of nutrient removed in grain harvest to units of nutrient applied, such as corn N harvested relative to fertilizer N applied (PFPN, lb/lb).” Advances in corn genetics and changes in farmers’ management practices have resulted in more pounds of grain produced for every pound of nitrogen applied. Dr. Richard Ferguson shared, “The average PFP of fertilizer N for corn in Nebraska was estimated to average 1.16 bu/lb N in 2012 compared to 0.57 bu/lb N in 1965. This represents a doubling in PFP for fertilizer N applied to corn. The trend of increase was linear from 1965 to 2012. Assuming a grain N concentration of 1.2% at 84.5% dry wt. or 0.67 lb N/bu, the PFPN converts to 0.79 lb of grain N per lb of fertilizer N applied in 2012 compared with 0.38 lb/lb in 1965.” That’s quite an increase in nitrogen use efficiency!

Another way farmers have been looking to increase nitrogen use efficiency is to compare nitrogen rates and timing of the fertilizer applications. We’ve had some on-farm research studies recently look at sidedress applications using either the UNL equation/Maize N model or industry models such as Climate Field View and Granular. In all these studies, the recommended rate was compared to rates that were at least 30 or 50 pounds over and under the recommended rate. In 2020, there were two nitrogen rate and timing studies in the area partially sponsored by the UBBNRD. A York County study found no yield differences between applications of spring anhydrous of 135, 185, and 235 lbs/ac. The same farmer also did a nitrogen rate X timing study in Hamilton County. He compared Fall vs. Spring vs. Split application rates of anhydrous + UAN of 205 vs. 255 lb/ac for each timing. There were no yield differences with any of the timings and rates. Take homes: In none of the studies did the addition of 30-50 lbs N/ac above the recommended rate increase the yield statistically. A few of these studies also compared side-dress applications vs. pre-plant alone. One situation resulted in a statistically lower yield with pre-plant alone while the others resulted in no yield differences. I’ve compiled these results in a table at http://jenreesources.com.

These nitrogen rate and timing studies could provide farmers a way to assess for their own operations. I’ve mentioned the precision nutrient management studies (https://go.unl.edu/4rvw) for several months. If you weren’t sure if it could apply to your situation, I was told that those don’t have to be precision nutrient applied. So, if you’re interested, please let me know and we can work out the details. There is a $1300 stipend for that specific study. There’s also up to $300 reimbursement from UBBNRD for water quality related studies. I’m currently working through on-farm research protocols for 2021. If you have a production and/or product-related question you want to test on your own farm, please contact me or your local Extension educator and we’d be happy to help you set up a study!

*Note: End of column for newspapers.*
*For mobile devices, please scroll left-right to read the first table below.*


YearCounty/
Irrigation
Pre-PlantIn-Season Rate/
Yield
In-Season Rate/
Yield
In-Season Rate/
Yield
In-Season Rate/
Yield
Other
2015Dodge
(Maize N model)
12 lb N/ac MAP (fall)
80 lb N/ac 32% UAN at plant
70 lb N/ac
222 bu/ac
100 lb N/ac
220 bu/ac
2015Dodge
(Maize N model)
12 lb N/ac MAP (fall)
80 lb N/ac 32% UAN at plant
70 lb N/ac
221 bu/ac
100 lb N/ac
221 bu/ac
2016Dodge
Rainfed
(Climate Field View)
78 lb N as 32% UAN in April30 lb N/ac as 32%+10%ATS (SD)
224 bu/ac
60 lb N/ac as 32%+10%ATS (SD)
226 bu/ac
90 lb N/ac as 32%+10% ATS (SD)
239 bu/ac
2016Dodge
Non-irrigated
(Climate Field View)
78 lb N as 32% UAN in April35 lb N/ac as 32%+10%ATS (SD)
196 bu/ac
65 lb N/ac as 32%+10% ATS (SD)
201 bu/ac
95 lb N/ac as 32%+10%ATS (SD)
201 bu/ac
2016Dodge Pivot70 lb N/ac as NH3110 lb N/ac
247 bu/ac
140 lb N/ac
250 bu/ac
170 lb N/ac
249 bu/ac
2017Dodge
Pivot (4″)
70 lb N as 32% UAN Spring110 lb N/ac 32% (SD)
239 bu/ac
140 lb N/ac 32%
(SD)
243 bu/ac
170 lb N/ac 32% (SD)
251 bu/ac
210 lb N/ac 32% Spring Pre-plant
216 bu/ac*
2017Saunders
Non-irrigated
100 lb N/ac as 32% UAN Spring40 lb N/ac 32% (SD)

195 bu/ac
40 lb N/ac 32%+Humic acid (SD)
199 bu/ac
75 lb N/ac 32% (SD)

200 bu/ac
140 lb N/ac 32% Spring Pre-Plant
193 bu/ac
2017Saunders
Non-irrigated
100 lb N/ac as 32% UAN Spring40 lb N/ac 32% (SD)

183 bu/ac
40 lb N/ac 32%+Humic acid (SD)
183 bu/ac
75 lb N/ac 32% (SD)

185 bu/ac
140 lb N/ac 32% Spring Pre-Plant
185 bu/ac
2018Gage
Non-irrigated
150 lb N as 32% UAN in April. Rye cover crop.0 lb N/ac as AMS (SD)
137 bu/ac*
50 lb N/ac as AMS (SD)
161 bu/ac
100lb N/ac as AMS (SD)
151 bu/ac
2018Franklin
Pivot (4″)
None. Cover crop mix0 lb N/ac as Urea broadcast

210 bu/ac*
100 lb N/ac as Urea broadcast

254 bu/ac
175 lb N/ac as Urea broadcast

272 bu/ac
250 lb N/ac as Urea broadcast
275 bu/ac
*Denotes that yield for the treatment was statistically different from others for a given year and location at the 90% confidence level. (SD)=Sidedress application.

2020 York Spring Anhydrous Nitrogen Rate on Corn
This study essentially showed what the previous studies had: that less nitrogen can be applied without hurting yield or net return. This study is sponsored in part by the UBBNRD.

Pre-PlantIn-seasonlbs N/bu grainYieldMarginal Net Return
110 lb N/ac spring NH3 (March)25 lb N/ac as UAN May0.73 C184 A$599.14 A
160 lb N/ac spring NH3 (March)25 lb N/ac as UAN May0.98 B189 A$600.38 A
210 lb N/ac spring NH3 (March)25 lb N/ac as UAN May1.23 A191 A$594.88 A
*Values with the same letter are not statistically different at a 90% confidence level. Marginal net return based on $3.51/bu corn, $8/ac for the anhydrous application cost, $0.28/lb N as anhydrous, and $0.35/lb N as UAN.

2020 Hamilton County Evaluating Nitrogen Rate and Timing on Corn
This study showed no difference in nitrogen timing nor rate on yield and showed less nitrogen can be applied without impacting yield. For reference, the UNL economical N recommendation for this field was 232 lb/ac N if applied in the fall, 190 lb/ac N if applied in the spring, and 156 lb/ac N if split applied. With a lbs N/bu grain of 1.0 or greater, it would be interesting to see this study conducted again using lower nitrogen rates. Soil samples down to 6 feet were taken by the farmer and the results did not find leaching in any treatments in this study. This study is sponsored in part by the UBBNRD.

Pre-PlantIn-seasonlbs N/bu grainYieldMarginal Net Return
180 lb N/ac Fall NH325 lb N/ac as UAN May1.03 B199 A$629.85 A
230 lb N/ac Fall NH325 lb N/ac as UAN May1.27 A201 A$625.49 A
180 lb N/ac Spring NH325 lb N/ac as UAN May1.02 B201 A$638.30 A
230 lb N/ac Spring NH325 lb N/ac as UAN May1.24 A206 A$641.70 A
120 lb/ac N Spring NH325 lb N/ac as UAN May
60 lb N/ac side-dress V8
1.00 B205 A$645.69 A
170 lb/ac N Spring NH325 lb N/ac as UAN May
60 lb N/ac side-dress V8
1.24 A206 A$633.50 A
Values with the same letter are not significantly different at a 90% confidence level. Marginal net return based on $3.51 bu corn, $0.28/lb N as anhydrous ammonia, $8.00/ac for anhdryous application, $0.35/lb for UAN applied with herbicide or as a sidedress, and $3/ac for sidedress UAN application.

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