How to plan an on-farm strip trial

Define the comparison before laying out strips

Write a question that can be answered by the measurements you can actually collect. A seeding-rate comparison needs established population and harvest data. A timing comparison needs actual application dates and crop stages. If product, rate and timing all change together, the result concerns that package. It cannot identify which change caused a difference.

Name the protocol owner, grower, field, crop and season. Specify the normal practice used as the check. Record what must remain consistent, such as hybrid or variety, planting date, fertility, harvest method and grain-moisture basis. Ask the person operating the equipment to read the plan before application. A design that cannot be applied or harvested accurately will not become a fair comparison through later analysis.

Nebraska Extension’s 10 Steps for On-Farm Research Success recommends deciding the question and required data first, accounting for field variation, and using replication and randomization. The Nebraska example generally recommends at least five replications. Have the research advisor choose a design appropriate to the question and field rather than treating a single paired pass as a replicated experiment.

Choose blocks and randomize treatment order

Walk the proposed area and compare its soil, slope, drainage, crop history and known trouble spots. Lay out blocks so treatments within each block have a reasonable comparison. A strip crossing a drowned-out depression while its check stays on higher ground can reflect field variation. Photograph those conditions before they become hidden by the crop.

Assign each block and strip an ID that will survive the whole season. Randomize treatment placement within blocks before application. Keep the resulting assignment with the original plan. Alternating the same treatment on the same side of every pair can align treatment with a productivity gradient. Replication provides repeated comparisons; randomization addresses systematic placement bias. The Nebraska guide explains both and discusses buffers where one treatment could affect its neighbor. Source: Nebraska Extension, 2016.

Match strip widths to the application and harvest equipment. Write down the intended interior harvest width and how border rows will be handled. Mark starts, ends, headlands and turn areas. Agree on buffers with the research advisor when drift, fertilizer movement or equipment overlap could affect an adjacent treatment. Do this before the passes are made.

Keep an application record by strip

The planned map and the actual application record are different documents. Record application date, operator, equipment, treatment identification, actual rate and units for each strip. Where relevant, retain product label, lot, crop stage and weather observations. Keep the operator’s source file with its own date. A voice note can explain an interruption but cannot replace a missing application quantity.

If the operator skips a strip, switches treatment order or stops midway, record the exact departure. Locate the stopping point and photograph any physical marker. Preserve the planned assignment and write an amended description beside it. Do not silently rename strips to make the actual work match the plan. That can disconnect field observations from harvest data.

Before leaving, reconcile the operator’s record against the map. Ask whether remaining product, monitor totals or bag labels support the stated application. Unresolved differences should reach the protocol owner while a return inspection can still help. A small uncertainty at planting can become impossible to resolve after harvest.

Measure crop response at comparable times

Choose observation dates based on the trial question. For a stand-establishment comparison, use the same count method and timing relative to emergence in each strip. Record measured row length and spacing, raw live-plant counts and any gaps. Do not compare a healthy strip sampled in its best section with a check sampled at the headland.

For injury or disease ratings, identify the scale, observer, crop stage and sample selection. Keep the same method across treatments and blocks. A directed photograph of the worst area is useful evidence, but it is not a substitute for a planned representative assessment. Label directed observations so they do not accidentally enter the treatment mean.

Use a visit after an unusual event to document differences that could affect interpretation. Examples include standing water, lodging, equipment traffic and missed applications. Separate what you saw from a grower’s explanation. Take matching views across the pair when practical, keeping strip IDs visible in the notes.

Harvest measurements and quality checks

Before harvesting the trial, review strip IDs with the operator and confirm how loads or monitor segments will be separated. Retain harvested length, actual width, area, grain weight, moisture and units for every strip. A field-wide average loses the experimental comparison. Keep raw files and any corrected analysis table as distinct versions.

Iowa State’s Tips for Calibrating Your Combine’s Yield Monitor recommends checking sensors and scales, following the display manufacturer’s calibration process and collecting calibration loads across different grain-flow rates. It also calls for checking moisture and monitoring accuracy as conditions change. Save the calibration record and identify which harvest data it applies to. A precisely displayed yield can still be based on a poor calibration.

Reconcile harvested area with the actual strip, excluding turns and any sections the protocol did not harvest. Document why a section was omitted. If a load mixed treatments, keep the measurement and the mixing note, then ask the research advisor how it affects analysis. Do not create a replacement weight from memory.

Worked example: recording a split application

In PropelMapper, start the visit at the trial’s place and speak the block, strip ID, stopping point and operator’s explanation. Add a photo and a typed note distinguishing the planned treatment from what was applied. Use readings for measurements the team has defined, with units stated in the note. A Follow-up task can assign collection of the operator’s application record to the responsible person.

Once connected, compare the draft with the original recording and photographs. In the report, identify the departure and the research advisor’s decision. Metrics exports can carry the team’s readings into CSV or Excel for analysis. Statistical testing, moisture corrections and experimental exclusions need a documented calculation outside the visit narrative; do not describe PropelMapper as a trial-analysis engine.

Interpretation and the next season’s decision

Present results by strip and block before any treatment mean. State the statistical method, uncertainty and exclusions with the advisor’s interpretation. A numerical difference is not enough to establish a dependable response. A single field and season also leave questions about other soils, weather and management. Keep the conclusion within the comparison actually made.

For economics, show the price assumption, additional treatment cost and relevant application or harvest costs. Yield response and net return answer different questions. A positive yield difference can still leave an unfavorable margin under the stated costs. Label the date and source of each price; do not turn a trial example into a customer outcome claim.

Close the report with the next decision: repeat the trial, adjust the protocol or adopt a change under specified conditions. List the missing records that could alter that decision. The trial plan PDF, Word plan and Excel tables provide a place to organize the layout and raw measurements.