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Sensor-Based N Fertigation

Understanding the Soil Microbiome: For those interested, this Friday, March 3, will be our last Friday conversation on ‘understanding the soil microbiome’ at the 4-H Building in York from 10 a.m.-Noon. Dr. Rhae Drijber, UNL soil microbiologist, will kick off our conversation and I’m looking forward to the discussion. If you plan to attend, please let us know at 402-362-5508.

March 4 Gardening Workshop will be held from 10 a.m.-Noon at the 4-H Building in York. Sarah Browning, Extension Educator, will share on vegetable planting basics such as site selection, rotational plan, summer care, and troubleshooting problems such as insects/diseases/weeds. Please bring your questions! This workshop is sponsored by the UBBNRD and Nebraska Extension; there’s no charge and refreshments are provided. No RSVP is required, but it does help with refreshments if you could please let us know at 402-362-6601 or 402-362-5508. If you’re interested in gardening, but don’t have the space at home, check out the Project GROW community garden in York. Plots are available for the 2023 growing season. You can reserve your space now or come to the Gardening Workshop and sign up in person.

Sensor-Based Nitrogen Fertigation: This week also brings the last of our on-farm research updates (Mar. 1 in North Platte, Mar. 2 in Kearney, and Mar. 3 in Beatrice). You can still sign up at  

One of the most impactful on-farm research studies being shared (I feel) is on sensor-based nitrogen fertigation occurring since 2019. It’s similar in concept to Project Sense, for those of you familiar with sensors being retrofitted on ground rigs for in-season nitrogen applications.

Sensors mounted onto a drone could allow for improved nitrogen use efficiency (NUE) by responding to actual plant needs in season. A grower determined base rate was applied to the field across treatments. Then grower fertigation management was compared to the sensor-based approach in 15 degree sectors on half a pivot. Indicator and reference plots in the field received at least 30 lb/ac less N and 30 lb/ac more N respectively and were established around V7. The field was flown weekly with a drone, imagery was analyzed, and fertigation decisions were made for each treatment sector.

The treatments were: 1) Grower rate 2) Risk averse post-establishment (RAP) (fertigation events applied up to R4 but 30 lb N/ac applied when needed between V9-V14) and 3) Risk averse post-establishment Increased Rate (RAP-IR) (fertigation events applied up to R4 but 60 lb N/ac applied when needed between V9-V14).

Since the beginning of this effort, 100% of the RAP-based sensor treatments were more efficient across all sites than the typical N grower management. Encouraging to me about this method is that it’s all based on what the plant needs after what the soil provides to the plant. There’s no determination of an N rate ahead of time based on plant removal, yield goal, etc.

There were 4 studies in 2022, but I will share on two of them. In a Hall county field with silt loam soils, both sensor based fertigation treatments triggered a total application of 95 lb N/ac vs. grower applying 196 lb N/ac. The grower treatment resulted in a yield of 277 bu/ac at 0.71 lb N/bu NUE. The two sensor based treatments resulted in yields of 271 and 274 bu/ac at only 0.35 lb N/bu NUE! That was pretty incredible for me to see 0.35 NUE and those kind of yields! It shows there is opportunity to consider further reductions in nitrogen applications. At a Saunders county field, no grower rate was used and the beginning base rate was only 33 lb N/ac. The RAP sensor treatment had 108 lb N/ac total applied yielding 258 bu/ac with 0.42 lb N/bu NUE. The RAP-IR sensor treatment had 101 lb N/ac total applied yielding 274 bu/ac with a 0.37 lb N/bu NUE.

You can read more details of this study via the online version of the 2023 On-Farm Research book found at: (beginning on page 80). For 2023, growers interested in trying this via on-farm research can receive monetary support through a Conservation Innovation Grant to help with purchasing fertigation equipment and/or for the aerial imagery services through Sentinel Fertigation. I would love to see 5 of these in our area of the State this coming year. Please let me or Laura Thompson ( know if you’re interested!

You can still register for the CPIA Conference or walk-in the day of the event. Really practical info. for growers and ag industry!

Note: Beatrice was rescheduled to March 3rd. You can still RSVP for this week’s meetings or else walk in.

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