Demonstration/Strip Trials - What should you learn from them?

The drought experienced this year has been unique. Drought occurs somewhere in Wisconsin nearly every production season. What has been unique this year is how widespread the drought is and the variability seen even between fields within a farm. In one field, corn might be barren and across the road good yields are measured. In many ways I was surprised to see corn hang-on as long as it did given the length of time no rain was received. In some of the fields yield-checked, we are finding ears with 16-18 kernel rows and 30-40 kernels per row.

Evaluating last year’s 'experiments' and using the lessons learned will help with next year's crop. Some new practices work and fit into your management style, others don't.

Every fall many farmers visit and evaluate hybrid demonstration plots planted by seed companies and county Extension personnel, among others. When checking out these plots, it's important to keep in mind their relative value and limitations. Demonstration plots may be useful in providing information on certain hybrid traits, especially those that are usually not reported in state corn performance summaries.

Use field days to make careful observations and ask questions, but reserve any decisions until you have seen the "numbers." Appearances can be deceiving.

In general, there are two major categories of on-farm research trials. The first is replicated trials that try to account for field variability with repeated randomized comparisons. Examples include trials conducted by universities and by public and private plant breeders. The other type is non-replicated demonstrations such as yield contests, on-farm yield claims, demonstration/strip trials and farmer observation and experience.

Field variability alone can easily account for differences of 10 to 50 bushels per acre. Don't put much stock in results from ONE LOCATION AND ONE YEAR, even if the trial is well run and reliable. This is especially important in years with tremendous variability in growing conditions. Years differ and the results from other locations may more closely match your conditions next year. Use data and observations from university trials, local demonstration plots, and then your own on-farm trials to look for consistent trends.

A few suggestions on how to evaluate research test plots:

1. Walk into plots and check plant populations. Hybrids with large ears or two ears per plant may have thin stands.
2. Scout for pest problems. Hybrid differences for pest resistance and tolerance should be monitored and noted all season, but will be most apparent in the fall. Counting dropped ears is a good way to measure hybrid ear retention and tolerance to European corn borers.
3. Check for goose-necked stalks. This is often root pruning caused by corn rootworms. Hybrids differ in their ability to regrow pruned roots.
4. Find out if the seed treatments (seed applied fungicides and insecticides) applied varied among hybrids planted, e.g. were the hybrids treated with the same seed applied insecticide at the same rate? Differences in treatments may affect final stand and injury caused by insects and diseases.
5. Differences in standability will not show up until later in the season and/or until after a wind storm. Pinch or split the lower stalk to see whether the stalk pith is beginning to rot.
6. Break ears in two to check relative kernel development of different hybrids. Hybrids that look most healthy and green may be more immature than others. Don't confuse good late season plant health ("stay green") with late maturity.
7. Visual observation of ear-tip fill, ear length, number of kernel rows, and kernel depth, etc. don't tell you much about actual yield potential. Hybrid differences are common for tip kernel abortion (“tip dieback” or “tip-back”) and “zipper ears” (missing kernel rows). Even if corn ear tips are not filled completely, due to poor pollination or kernel abortion, yield potential may not be affected significantly, if at all, because the numbers of kernels per row may still be above normal.
8. Be careful with test plots consisting predominately of one company's hybrids. Odds are stacked in their favor!
9. Other observations that should be made:
• Dry down rate
• Test weight
• Disease damage
• Grain quality
• Ease of combine-shelling or picking

Further Reading

Fall Scouting and Evaluating Field Test Plots and Demonstration Strips