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Understanding crop performance tests – part I
Dr. Victor Martin

As of July 27 much of the central part of Kansas is rated as abnormally dry with little change from last week. This still includes all of Barton County except for the southwest corner of the county. Pawnee County is still okay but most of Stafford County is also abnormally dry. This past week’s heat should intensify these dry conditions unless the showers promised this weekend are substantial and the cooler temperatures hold.  The six to ten-day outlook (Aug. 3 to 7) indicates below normal temperatures and precipitation. The eight to 14-day outlook (Aug. 5 to 11) indicates a return to normal to slightly above normal conditions and slightly below normal precipitation. The wheat performance tests from KSU are available, fall harvested crops will be in a few months for corn, soybeans, and grain sorghum, along with test plots by seed companies and others. Lots of yield information is available and can be quite valuable but how do you use it and what does it mean?  

First, here is a link to the KSU wheat performance tests: Let’s discuss how to use the replicated, statistically analyzed KSU tests first. Here we aren’t talking about the strip tests often put out by county/district extension agents often used for wheat tours in the spring. How are they done?  

• Companies pay to enter varieties/hybrids in these tests with a few exceptions, decide which site locations to place them at, and whether dryland or irrigated tests or both. This means that a variety/hybrid of interest may not be included in a test. Breeders may have an experimental cultivar of interest in studies with a designation that will not be the release name.

• The sites are located throughout the state. Some are on KSU research centers and experiment fields while some are with producer cooperators. There may or may not be a site close to a given area or the soil type may be different, etc.  

• The size of the plots may vary but for row crops typically four rows wide and of various lengths. They are replicated, typically four times in a randomized complete block design to allow for statistical analysis. They are arranged to minimize the effects of anything other than the hybrid/variety. Things like slope, soil type, and field edge effects.

• The entire study is treated uniformly in terms of cultural practices such as seeding rate, fertilizer, pest control, etc. The area is treated using best practices to optimize yields. Plots are planted using specialized equipment as is harvest. Occasionally a special test will be conducted.

• Typically, notes are taken but the detail of notes such as flowering dates, maturity, etc. depend on the location. You will normally be told things such as fertilizer and irrigation rates, pesticide applications, plant populations, and dates of operations along with anything unusual that was noticed. Especially for wheat, personnel will evaluate for diseases and insect damage.

• Harvest is typically conducted with plot combines with automatic weighing systems and data collected normally includes not just yield but moisture and test weight. 

• These data are then statistically analyzed for significance, summarized and then released to the public.

Next week, how to use these tests.

Dr. Victor L. Martin is the agriculture instructor/coordinator for Barton Community College. He can be reached at 620-792-9207, ext. 207, or