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Dennis Epplin and Jim Morrison Extension Educators, Crop Systems University of Illinois Extension

Designing Valid On-Farm “Demonstrations” Using Manure 2007 Livestock Manure Management Conferences March 13, Effingham March 15, Princeton. Dennis Epplin and Jim Morrison Extension Educators, Crop Systems University of Illinois Extension. Outline. Why conduct them?

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Dennis Epplin and Jim Morrison Extension Educators, Crop Systems University of Illinois Extension

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  1. Designing Valid On-Farm “Demonstrations” Using Manure2007 Livestock Manure Management ConferencesMarch 13, EffinghamMarch 15, Princeton Dennis Epplin and Jim Morrison Extension Educators, Crop Systems University of Illinois Extension

  2. Outline • Why conduct them? • Where to start or what to do first? • “Demonstration” vs. “Strip trial” vs. “Research” • Plan ahead • Making sense of the data • Examples of on-farm trials

  3. Why Conduct Them? • Producer interest and ability • Desire to be more “in control” and predictive • Availability and use of yield monitors, computers, precision controls, etc. • Organizations (SWCD, Extension, etc.) and funding (SARE, C2000, etc.) are in place

  4. Where to Start – What to do First? • Planning is critical: • What is the objective or goal? • Anything “special” needed (equipment, analysis, etc.)? • What treatments should be included? • What data will be recorded (and by whom)? • Where will it be located? • Who will plant, monitor, harvest, etc.? • What’s the cost and who’s paying? • Choose representative area of field: • Soil type, slope, and drainage • Tillage and fertility • Know past cropping history (and inputs) of field

  5. Where to Start – What to do First? (more) • Some basics to remember: • Keep the project as simple as possible • Keep all practices (hybrid, plant population, herbicide, etc.) constant, except for the one factor that is changed (the “treatment”). • “Quality control” is critical. • Don’t draw conclusions before all the info is gathered; and be ready for unexpected results.

  6. What’s the difference between . . • Demonstration – • we know what the outcome will be • Strip trial – • no replication (at a site) with this design method • no estimate of error, not predictive • “treated” strip and a “check” (2 strips) Examples -

  7. Research – • provides predictive ability – helps with decision making • assumes that we don’t know the outcome, at least over sites • replications allow for statistical analysis • is the difference due to “chance” or is it “real”? • multiple locations, multiple years important

  8. Plan Ahead • If we expect results to be more weather-related, we need more years. • If we expect results to be more field-affected, we need more fields. • 2 to 4 reps per location - depending upon variability and number of sites. May need more reps than 4. • Randomize reps • Use a strip size wider than the combine to allow borders. • Measure yields accurately • Convert to standard moisture

  9. Design Example –Randomized Complete Block Rep 1 or Block 1 Rep 2 or Block 2 Rep 3 or Block 3 What’s one problem with the arrangement of treatments?

  10. Design Example – Split-Plot Design Rep 1 Rep 2 Rep 3 Red Clover No Clover No Clover Red Clover Red Clover No Clover

  11. Making Sense (and cents) of the Data • Computer spreadsheet (Excel) is essential for making use of on-farm trials. • Replicating treatments allows you to: • estimate random variation, and • see if treatment effects stand out from this variation • Randomizing treatments helps eliminate bias.

  12. Making Sense (and cents) of the Data, cont. • Statistics allow you to determine if the difference between treatments was the result of “chance” or whether it was “real” (probably NOT due just to chance). • Include economics • Keep record of what was done and what was found.

  13. Seeding Rate 40 50 60 70 80 90 LSD 0.10 Yield, bpa46.7 49.4 50.8 51.2 51.5 51.0 2.4 Analyze Results Properly – NOT like this . . . “Best” seeding rate = 80, or anything from 50 to 90 since they are “not different”?

  14. Rather, like this . . .

  15. Manure vs. Commercial Fertilizer • Variation in nutrient content • Can we obtain representative sample(s) for analysis? • In most cases manure is applied before analysis is back from laboratory • Can manure be uniformly applied? • How much “error” is acceptable?

  16. On-Farm Example 1 -Manure Applicator Calibration Project

  17. 4600 gpa (150 lbs. N per acre), April 11 Field planted to corn Soil test prior to manure Manure analysis PSNT taken Field history-crops, inputs Knowledgeable of rate?

  18. On-Farm Example 2 -Paired-Strip Trial, using “t test” • A two-treatment trial • Treatments are paired together in adjoining strips. • Each pair contains one strip each of the two treatments. • Analysis indicates whether the difference between treatments is “real” or whether it is due to “random variation” in the field.

  19. Example - (Manure) (Anhy. Am.) (“real” or random?) “t value” If Cell 8 > 1.895 = 90% sure treatments really differ If Cell 8 > 2.365 = 95% sure treatments really differ

  20. On-Farm Example 3 -How much of the N in manure is available to the corn crop? • Manure to be applied to wheat stubble for the following corn crop. • Field, or area of study, should have a recent soil test. • Ideally, field should not have a history of manure application. • Have a nutrient analysis of the manure.

  21. Steps • Apply manure at a single, measured rate assuming to provide 100 lbs. N per acre. • Apply manure in single strips, randomly assigned to 1 of 4 strips within each of 6-8 reps. • In spring (or fall), apply 50, 100, 150 lbs. fertilizer N randomly assigned to the other 3 strips within each rep. • Width of manure & fertilizer strips depends upon applicator, planter, and combine. Keep as narrow as practical. • Length should be minimum of 250 feet.

  22. Steps, more • Harvest the center rows of each strip. Leaving 2-4 rows on each side as buffer. • May be helpful to take PSNT, and SPAD readings (after pollination). • Yields calculated from each strip. • Data analyzed using regression over 3 fertilizer N rates. Then match yield of the manured strip against this curve. This will show at what fertilizer N rate the yield = the manure yield. • This can be an estimate of the N coming from the manure.

  23. Summary • Make it a team effort – • producers, industry, university/agency • Keep it simple • Replicate and randomize • Stay uniform • Harvest individual plots • Remain objective and don’t ignore unexpected results • Multiple years, multiple sites (locations can substitute for years, but they usually do not sample the weather well)

  24. Acknowledgements • Emerson Nafziger, Extension crops specialist, University of Illinois • Better Crops, Vol. 81, No. 3 • How to Conduct Research on Your Farm or Ranch, SARE, www.sare.org/publications/research.htm

  25. Thank you !Questions - Comments ?

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