Extension/Research Information

2002 Ohio Forage Performance Trials

Ohio State University Extension
Ohio Agricultural Research and Development Center
The Ohio State University

Horticulture and Crop Science
Series 195
November 2002


Interpreting Yield Data

     Yield data are reported in Tables 3 through 14. Details of establishment and management of each test are listed in footnotes below the tables. Least significant differences (LSD) are listed at the bottom of Tables 4 through 14. Differences between varieties are significant only if they are equal to or greater than the LSD value. If a given variety out yields another variety by as much or more than the LSD value, then we are 95% sure that the yield difference is real, with only a 5% probability that the difference is due to chance alone. For example, if variety X is 0.50 ton/acre higher in yield than variety Y, then this difference is statistically significant if the LSD is 0.50 or less. If the LSD is 0.51 or greater, then we are less confident that variety X really is higher yielding than variety Y under the conditions of the test.

     The CV value or coefficient of variation, listed at the bottom of each table is used as a measure of the precision of the experiment. Lower CV values will generally relate to lower experimental error in the trial. Uncontrollable or unmeasurable variations in soil fertility, soil drainage, and other environmental factors contribute to greater experimental error and higher CV values.

     Results reported here should be representative of what might occur throughout the state but would be most applicable under environmental and management conditions similar to those of the tests. The relative yields of all forage legume varieties are affected by crop management and by environmental factors including soil type, winter conditions, soil moisture conditions, diseases, and insects. These factors vary with the year and location.


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