Dave Mengel, Kansas State University Multi-State Winter Wheat Sensor Project,

Participants Kansas: Dave Mengel, Kent Martin, Doug Shoup Oklahoma: Bill Raun, Brian Arnall Missouri: Peter Scharf Ohio: Robert Mullin Virginia: Wade Thomasson Maryland: Josh McGrath Others expressed interest but were not able to participate this past year.

Objectives Conduct a common experiment across a broad range of conditions to: Evaluate sensor performance at predicting N fertilizer needs Generate a common data set to assist in algorithm development Develop a community of individuals interested in using sensors to enhance yield and NUE in wheat

The Experiment Randomized complete block design, four reps, eight common treatments: No N control, Reference strip, six rates of topdress N 0, 25, 50, 75, 100, 125 all with 25 applied at seeding. Most topdress rates applied a F 4/5. Where multiple topdress rates were used, first applied as a uniform rate and treatments were applied at the second topdressing. NDVI measurements made at several times, but most focused on green-up through jointing. All participants used GreenSeeker, some used additional sensors. All participants measured yield, TW and grain N.

The Experiment cont. Most participants added additional treatments. These included: Different types of reference strips, or times of reference strip application Additional times of N application Multiple topdressings Single topdressings at later dates Feekes 7 or 9 Additional sensors or measurements

Preliminary Results Results are not in from all sites Good range of yields and N response Sensors appeared to be able to detect differences in N needs at Feekes 4 /5 (and at later growth stages) Appeared to be significant N loss after sensing at some sites, based on differences between Reference and TD tmt yields

Results: Kansas Locations Yates Center North Farm McPher East McPher West Garden City Stanton NDVI, ref, F4/ RI Yld potential, ref Yld observed, ref Topdress N rec Yld rec N rate Opt td N obs Yld obs, opt td N

Results: Other Locations VTOSU Lahom OSU Henn OSU LCB NDVI, ref, F4/ RI Yld potential, ref Yld observed, ref Topdress N rec Yld rec N rate Opt td N rate obs Yld obs, opt td N

Proposed activity for Continue project for second year Use the same basic design: True control Reference Strip Topdress N applications applied on top of “Farmer Practice” fall or fall/spring application Kansas will apply 25 pounds N in the fall with P at seeding Six topdress rates, pounds N per acre applied F4/5, F7, F9, what ever is appropriate in your area Sensor measurements at time of application

All are invited to participate If you are interested, please contact me at: