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.

About jenreesources

I'm the Crops and Water Extension Educator for York and Seward counties in Nebraska with a focus in irrigated crop production and plant pathology.

Posted on March 7, 2021, in JenREES Columns, on-farm research and tagged , , , . Bookmark the permalink. Leave a comment.

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