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OFT key1994 Test Results

Introduction

This bulletin details many of the on-farm tests performed by farmers with help from fieldmen, extension agents, and researchers in the Pacific Northwest during 1993-94. Most are connected in some way to the STEEP II On-farm Testing project, a federally funded effort aimed at helping farmers make use of on-farm tests to increase development and adoption of soil and resource conserving farming methods. The OFT project is lead by extension workers from Idaho, Oregon, and Washington, and provides technical assistance and educational materials to farmers through their local Cooperative Extension office. We also work with Ag industry, Conservation Districts, and other organizations. For more information on the project or on-farm testing, contact Stewart Wuest (509-335-3491). Also see the article on designing on-farm tests and the guide to resources later in this bulletin.

One of the most important aspects of a well designed on-farm test is replication. This is why I have put the data from each replication in the reports. Statistics help in deciding if measured differences in performance are due to the treatments applied or simply due to the random variation that exists in every field. If the difference between the treatments is greater than the "least significant difference at a 5% probability level" (LSD(5%)), we know that there is only a 5% probability that it was caused by random variation and not the treatments. Personal judgement and thought must go into any conclusion, and final decisions regarding a farming practice should reflect many economic and management factors and more than one year of tests. On-farm tests are designed to provide farmers with an accurate, low risk tool for exploring production options and making successful decisions.

Designing an On-farm Test

The on-farm test design presented here is aimed at measuring and comparing the performance of two or three different crop management strategies, or "treatments". An on-farm test can be used to measure performance in terms of yield, stand establishment, protein, water infiltration, weed counts, or other criteria. The treatments could be as modest as the application of fungicide in one treatment and not in the other, or as different as zero-till seeding compared to plow, cultivate, and seed, or even a comparison of different crop rotations.

Designing 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 shown that long, narrow, side-by-side strips replicated four to six times can produce a very accurate comparison. The longer the strips are, the better the data is likely to be. There have been many successful tests with four replications of 300 ft strips, but 750 ft or longer strips are more likely to produce accurate results. Four replications are recommended, but five or six replications should be used if the comparison might produce small or very important differences. It is difficult to understand the importance of adequate replication until you have had some experience trying to draw conclusions from data with only two or three replications. Try to resist the temptation to minimize the number of replications. With the availability of portable weighing equipment, eight to twelve strips can be harvested in less than three hours.

After deciding what the treatments are going to be, pick locations in the field where you can place the treatments in long, side-by-side strips. All strips in a replication should have an equal chance to perform well, in your best judgement. In other words, do not place one strip on flat ground and the other on a hill slope. Other areas to avoid are fence lines and field corners where extra fertilizer and tillage occur. Flip a coin to decide which treatment goes in which strip. Repeat for each replication. Replications can be next to each other, or in separate parts of the field.

When measurements are made, such as stand counts or yield, record them separately for each strip. The data can be analyzed statistically using a hand calculator and step-by-step formulas, a free, easy-to-use computer program from OSU called AGSTATS, or with help from your county extension agent. Even without statistics, a lot can be learned by looking at each replication to see if one treatment was consistently better than the other.

If you are a beginner at doing experiments, ask for some help from your extension agent or someone with OFT experience. Most likely a little discussion with an experienced experimenter will save a mistake or two and make your OFT more successful.

Guide to Resources

1992 Pacific Northwest On-farm Test Results. S.B. Wuest, B.C. Miller, R.J. Veseth, S.O. Guy, D.J. Wysocki and R.S. Karow. 1992. Department of Crop and Soil Sciences Technical Report 92-4, Washington State University, Pullman, WA. and

1993 Pacific Northwest On-Farm Test Results. S.B. Wuest, B.C. Miller, R.J. Veseth, S.O. Guy, D.J. Wysocki and R.S. Karow. 1993. Department of Crop and Soil Sciences Technical Report 94-1, Washington State University, Pullman WA.

These give results from previous year's on-farm tests.

On-Farm Testing: A Grower's Guide. B. Miller, E. Adams, P. Peterson and R. Karow. 1992. Washington State University Cooperative Extension EB1706.

A guide to designing and carrying out OFT. Includes forms for record keeping. 20 pages, $1.00. Order from WSU Cooperative Extension Bulletin Office (509-335-2857)

 
                         
                         
                         
 

Contact us: Hans Kok, (208)885-5971 | Accessibility | Copyright | Policies | WebStats | STEEP Acknowledgement
Hans Kok, WSU/UI Extension Conservation Tillage Specialist, UI Ag Science 231, PO Box 442339, Moscow, ID 83844 USA
Redesigned by Leila Styer, CAHE Computer Resource Unit; Maintained by Debbie Marsh, Dept. of Crop & Soil Sciences, WSU