Top 10 lessons learned in 6 years of on-farm sensor demos

1. > ? Top 10 lessons learnedin 6 years of on-farm sensor demos Peter Scharf University of Missouri

2. 123 fields

3. #11: Works with any kind of equipment

4. sensors Crop sensors can be used for sidedressing anhydrous…

5. …or sidedressing solution

6. …or with a high-clearance spinner

7. …with a big sprayer

8. …or a big injector #10.5: Farmers like toys

9. …but not AgLeader InSight, Deere, New Leader: no serial input! …With Raven, Raven Viper, Rawson, Falcon, or MidTech controllers (thanks, Scott!)

10. #10: Lots of preparation goes into a successful demo(or adoption)

11. Preparation • Recruit cooperators • Build brackets to hold sensors on the applicator • Controller: port?!, communication parameters, programming • Coordinate plan for preplant N • Apply high-N reference area • Plan for yield documentation

12. #9: It’s important to filter out readings from bare soil

13. Filtering soil • Not as easy as it sounds • Different ‘reflectance’ for: • Different soils • Same soil with different moisture levels • Same soil with different residue levels • If you don’t, you’ll put high N rates on thin (or nonexistent) stands • Angled sensors may also solve this problem

14. Bare soil cutoff? N rate = 220 High-N reference value Random 20 m of sensor dataV7, 2009 Average N rate with all data = 248 Average N rate with cutoff = 161

15. Bare soil cutoff value • When we do a demo, measuring bare soil is the first thing we do when we pull into a field • Then we set a cutoff value to discard any data at or near this value

16. #8: We can combine sensors with other information sources to make N rate decisions

17. We’ve combined sensors real-time with: • Yield zone maps • Add to sensor-based N rate in high-yield zones • Don’t modify in medium-yield zones • Subtract from sensor-based N rate in low-yield zones • Future N via lagoon effluent through pivot • Calculate sensor N rate, subtract lagoon N from rate

18. Yield zone example Productivity Zones and Treatment Layout Low: subtract 25 Medium: don’t change High: add 12

19. #7: Varying rates of liquid N (anhydrous or UAN solution) is hard

20. Varying flow rates is difficult • Double flow requires 4x pressure • Highest rate = highest pressure (100 psi?) • What happens as you drop pressure? • Distribution along bar or boom becomes uneven • Starts at about ¼ max (25 psi?) • N rate = ½ max • If top rate = 150, bottom rate = 75

21. Is this good enough? • Yes, but it would be better to have a wider range • New nozzle bodies with spring-loaded orifice • Orifice gets bigger as pressure increases • Available from Greenleaf, SprayTarget • Gives wide rates, even spread, and doesn’t pop hoses

22. #6: A good reference value is crucial

23. What about Virtual Reference Areas?

24. High-N reference area Best 5% from strip with 75 lb Pre-plant Best 3 sec from strip with 75 lb Pre-plant Average N rate = 96 Average N rate = 73 This N rate out-yielded producer rate by 18 bushels Average N rate = 43 Virtual reference example Producer N rate = 60

25. #5: Sensor values drift (Nitrogen need doesn’t)

26. Sensor values drift during the day

27. 8PM 6AM Sensor values drift during the day:Vis/NIR 8 days of measurements Same plant all day long

28. 0 6AM 8PM Error in N rate due to drift:Crop Circle Vis/NIR 100 50

29. 100 150 200 250 300 50 0 6AM 8PM Error in N rate due to drift:Greenseeker Vis/NIR

30. 100 150 200 50 0 6AM 8PM Greenseeker error in N rate reduced using NDVI equation

31. 100 150 50 0 6AM 8PM Greenseeker error in N rate reduced even more using correction equation

32. Why do sensor values drift during the day?

33. Next AM--dew PM Water effects on sensors Strips with producer N rate

34. watering Water changes sensor values

35. My recommendation: To avoid bad N rate decisions, re-measure high-N reference area at least every 2 hours (especially with Greenseeker)

36. High-N reference strips Crosswise high-N reference strips: a slick way to update high-N value Program system to update reference value every time you drive across them (Scott!) With a plane, you could do a lot of these in a hurry

37. #4: Watching the sensors work sells them

39. #3: Sensors can’t do everything

40. What can’t they do? • Sensors can’t distinguish between low N need and zero N need • ‘Top up’ is the wrong idea • Sensors can distinguish between low, medium, and high N need • Give them room to work by applying low or zero N preplant

41. #2: Timing is the biggest issue to producers, retailers, advisors

42. N sensor meeting, March 2009 • Producers, retailers, consultants, agencies, researchers, extension folks

43. Topics we could discuss • Obstacles to success • Timing risks and benefits • Need for preplant N • Sensor availability, pricing, issues • How many sensors are needed? • Producer vs. retailer applicators • Features you’d like to see • Corn vs. wheat (vs. cotton)

44. Obstacles to success • Need for high-N reference area • Cost of application equipment • Risk of not getting done at planned time • Good equations to predict N rate • Sensor cost • Limited range of liquid rates • Sensor values drift during the day (return to ref area?) • Conflicts with other field activities • Emergence skips = soil interference

45. Timing risks and benefits • Want to go early! • Sensors: 7-10 days later than normal sidedress • True for corn, cotton, wheat • Even people who always sidedress balk • Why? • Farmers like to get things done!

46. Timing risks and benefits • Risk: • Don’t get done with planned equipment (tractor, for example) • Solution: • Limit acres using sensors • Most variable land • Or land with biggest chance of reducing N rate • OR Have plan B for those years when you don’t get finished using planned equipment

47. Corn N timing: Full yield can be achieved even with late applications 1’ 2’ 4’ 7’ tassel

48. Field with low need for N Field with high need for N plant 18” 36” 80” Yield response to N depends a lot on need, not much on timing 8 small-plot trials in producer fields, 1997 Eight production corn fields, 1997

49. Timing risks and benefits • Benefit: • Low risk of N loss before crop uptake • How much of a benefit is this? • It depends on the weather—big benefit when wet • I estimate an average yield hit of 20 bu/acre this year between here and Missouri (windshield survey) • Big benefit last two years in Missouri • Widely used in southeastern U.S. • More rainfall than midwest

50. Sidedress N kicks butt in 2008(and 2009) +38 bushels 180 N at planting: LOST!! 110 N at knee high: DELIVERED!