1 / 21

Field Plots & Agricultural Research

Field Plots & Agricultural Research. Dr. Bob Kemerait & Dr. Eric Prostko University of Georgia Cooperative Extension Service April 2001. SAFETY FIRST. Topics. Demonstration plots vs replicated field trials Importance of replications Common experimental designs

Download Presentation

Field Plots & Agricultural Research

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Field Plots & Agricultural Research Dr. Bob Kemerait & Dr. Eric Prostko University of Georgia Cooperative Extension Service April 2001

  2. SAFETY FIRST

  3. Topics • Demonstration plots vs replicated field trials • Importance of replications • Common experimental designs • CRD, RCBD, Split-plot, Factorial • Small plots or large plots? • Plot maintenance • Data analysis & “significance” • Steps for a successful trial

  4. Demonstration Plots • Objectives • example/information for growers • simple qualitative comparisons • Advantages • simple to coordinate • simple to assess • Disadvantages • not very useful for quantitative study • may oversimplify issue

  5. High Nitrogen Normal Nitrogen Low Nitrogen Demonstration Plotsexample: rates of nitrogen on a field crop

  6. Replicated Field Plots • Objectives • desire to statistically compare treatments, varieties, etc. • Advantages • results recognized by scientific community • results suitable for making decisions • Disadvantages • more complicated to conduct

  7. Block 1 Block 2 Block 3 Block 4 Replicated Trialexample: effect of different rates of nitrogen

  8. How many replications are enough? • Generally, the more, the better! • increased “degrees of freedom” • easier to differentiate similar means • better assessment of variation within plot area • But consider………… • land constraints • time constraints • material constrains • (chemical, plants, etc.)

  9. You want how many reps???!!!! • Minimum number varies with discipline and researcher • Absolute minimum: 3 reps • Foliar fungicide programs: we like to see at least 4 reps • For soilborne diseases, including nematodes- we like 5 and even 6 reps • uneven distribution of organisms in the soil

  10. Common Types of Experimental Design • There is more than one type! • all of these designs are replicated • completely randomized design • appropriate if no variation in plot area • randomized complete block design • consider ONE source of variation in field!! • split-plot design • two treatment levels, consider interactions • factorial design

  11. Completely Randomized Design, 4 reps

  12. Randomized Complete Block, 4 reps

  13. BLK 1 BLK 2 BLK 3 BLK 4

  14. BLK 1 BLK 2 BLK 3 BLK 4

  15. Abound in-furrow No in-furrow Abound in-furrow No in-furrow No in-furrow Abound in-furrow Split-Plot Design

  16. Plot Maintenance • Importance cannot be overlooked • Uniformity in planting • Careful calibration of spray equipment • Fertility • Weed control • Insect control • Disease control • Field Tours & PRIDE

  17. Data Analysis • Statistical analysis can be tricky • consider specialists as references • Statistical Packages/Software • SAS--------MSTAT--------ARM • Analysis of Variance • are treatments significantly different? • Mean Separations • which means are different? • (Fisher’s Protected LSD)

  18. What’s so significant about “significance”? • Frequent question • Confusion over meaning • agricultural standard: 95% (usually) • “At the 95% confidence level, we can be sure that these means are different at least 95% of the time.”

  19. Getting Started with a Field Trial • Carefully determine your objectives • Decide on (limited) treatments • Develop an experimental design & plot plan • Secure necessary equipment and materials • Identify a conscientious cooperator • Choose your field site CAREFULLY • Remain safety oriented • Keep careful notes • Ask for help

  20. GOOD LUCK!

More Related