UPDATE - December 1995
Resources for Grower On-Farm Testing
Grower On-Farm Testing (OFT) is a key to developing more profitable and environmentally sound farming systems for the Pacific Northwest.
Why would producers take time from their busy schedule to conduct on-farm tests? The most common reasons are that farmers want to increase yields, protect the environment, and improve profitability. Farmers are becoming more aware that to accomplish these objectives they have to accurately evaluate available management options. On-farm testing is the only way farmers can discover and verify which practices perform the best on their farm. Using properly designed, replicated and conducted on-farm tests provides the best information in the shortest time -- without risking new practices on entire fields.
On-farm Testing ConsiderationsDesigning a test that will produce accurate, conclusive information requires replicated, side-by-side comparisons. This is the only way to distinguish yield differences that occur naturally between two strips from differences actually caused by the treatments. Extensive research in the Inland Pacific Northwest has demonstrated that natural field variability can commonly result 5-10 bushels per acre differences in wheat yield in side-by-side combine strips. Proper on-farm test designs with long, narrow, side-by-side strips replicated at least four or more times can separate the effects of natural variability and produce very accurate comparisons of treatment effects.
The longer the strips are, the better the data is likely to be, but that depends on the field landscape and soil variability. There have been many successful tests with four replications of 300 ft strips, but the research has shown that 750 ft or longer strips are more likely to produce accurate results. If yields are to be compared, as in most trials, make sure all the strips are wide enough to cut a full combine header width at harvest (plots wider than the header).
Briefly, the steps to laying out a valid test comparing two treatments commonly include: 1) choose an area in a field where a pair of long, side-by-side strips can be placed with the expectation that the yield (or weed pressure, or other factors to be measured) should be nearly equal; 2) assign the treatments to the plots randomly, such as with a coin toss; and 3) repeat the above process so there are at least four replications. The four replications could be next to each other, or in different areas of the field, or even in different fields. The best results occur when each replication is positioned so that variations in the field (high and low areas, soil variations, field borders, fertilizer overlaps, etc.) will be encountered equally by each strip in the replication.
Be sure to adequately mark the plots so you can locate them later in season! Measuring from reference points or stakes on field borders can also help to locate trials for harvest or other data collection.
When stand counts, yield or other measurements data can be analyzed statistically using a hand calculator and step-by-step formulas, using a free, easy-to-use computer program from OSU called AGSTATS, or with help from your county extension agent. A new version of AGSTATS should be available in early 1996. If you are a beginner at doing replicated experiments, ask for some help from your Extension Specialist or Agent, or others with on-farm testing experience. Most likely a discussion with someone who is an experienced on-farm tester will help avoid some mistakes and make your on-farm test more successful.
PNW On-Farm Testing Resources
After the initial project efforts on developing on-farm testing methodologies, the primary focus switched to was on educational progams how to do on-farm tests and assisting growers in conducting the field trials. Over 150 on-farm tests have been conducted by Northwest growers as part of the STEEP II on-farm testing project from 1992 through 1995. To share the results of these trials across the region, on-farm test summaries are compiled each year in Pacific Northwest On-Farm Test Results publications. Several "how-to" publications have also been completed, with a series of new publications in progress. The following are a listing of on-farm testing references and where to get them:
Pacific Northwest On-farm Test Results -- Descriptions, data and conclusions from tests complied at the end of each year. Copies are available for 1992, 1993, 1994, and 1995. Contact your local County Extension Office or call the WSU Crop and Soil Sciences Extension Office (509-335-2915).
For the following publications, contact your local County Extension Office or order directly from WSU Cooperative Extension Bulletin Office (509-335-2999).
On-Farm Testing: A Grower's Guide, WSU Cooperative Extension bulletin EB1706, 1992, $1.00.
Using an On-Farm Test for Variety Selection, Pacific Northwest Extension bulletin PNW486, 1995, $1.50.
On-Farm Test Record Form, Pacific Northwest Extension bulletin PNW487, 1995, $1.00.
us: Hans Kok, (208)885-5971
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