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Ben R. Carter and Keith D. Johnson* Research agronomist and professor of agronomy respectively, Dept. of Agronomy, Purdue University, West Lafayette, IN 47907-1150.
Experimental Methods Participating seed companies selected entries to be tested. Seed was sent to Purdue University for seeding and evaluation at the Feldun-Purdue Agricultural Center, located near Bedford in Lawrence County (Richard M. Huntrods, superintendent). Test plots were seeded into a conventionally prepared seedbed using a five-row press-wheel seeder with 6-inch row spacings.
Best management practices were administered to all studies. Optimum pH and fertility were provided and maintained. Hand weeding and herbicides were used as necessary to accomplish weed control. A flail-type forage harvester was used to harvest the plots. Hand samples were utilized for dry matter determination. Maturity stages at first harvest were taken and can be found in Table 1.
1997-2000 Growing Seasons (Refer to Appendix Figure 1) As the 1997 season progressed, the southern Indiana soils became very dry. Temperatures remained unusually cool causing the growing degree-day totals to be two weeks behind normal. This reduced the growth and lengthened the time between harvests. With timely rains in the fall, the plots entered the winter in good condition. Early season rains in 1998 gave a good first harvest. Extreme dry conditions during the summer slowed re-growth resulting in only one harvest for the year. With adequate rains and warm temperatures in October, fall growth was excellent. The 1999 season started out excellent after the first harvest, but rainfall diminished and later developed into extreme drought. The water-holding capacity of the soil became a production factor. Due to the lack of adequate rainfall, only two harvests were taken. Precipitation and temperature were favorable for the production of cool-season grasses in 2000. Three harvests of both grasses were completed in the 2000 season.
Presentation and Interpretation of Results Yields are reported as dry matter in tons per acre (T/A). Tables 2 and 3 summarize results of 1997 - 2000 yield trials. In Tables 2 and 3, varieties are listed in order of total yield to date. Within a column, varieties differing from each other by less than the respective LSD (least significant difference) were not significantly (probability > 0.05) different. Yields followed by an asterisk (*) are not significantly different from the highest value in the column. The CV (coefficient of variability) is the ratio of the standard deviation to the grand mean. It is used as a measure of the precision of the experiment. Lower CV indicates lower experimental error in the trial. Number of harvests within a year is listed at the bottom of each yield column. Table 4 contains a listing of commercially available entries, along with marketers, address, phone number, and contact person from the current listing of retail commercial seed distributors in the Indiana sales area. Questions can be directed to: Keith Johnson Dept. of Agronomy Purdue University 1150 Lilly Hall of Life Sciences West Lafayette, IN 47907-1150 Phone (765) 494-4800 FAX (765) 496-2926 E-Mail johnsonk@purdue.edu
How to Use Performance Information Information presented in the bulletin should be useful in selecting cool-season grass varieties for forage production in Indiana. When selecting an orchardgrass variety, a decision needs to be made if the seeding will be a pure stand or include a legume. We would suggest, based on observations from this study (Table 1), that early maturing varieties such as Potomac maturity type varieties are not desirable when a grass-legume mixture is desired. In past years, tall fescue had a poor reputation due to the presence of an endophytic fungus that results in poor animal performance. Publications about the endophytic fungus and the problems that may be encountered can be obtained from your local Purdue Cooperative Extension Service Office or from the Media Distribution Center. Releases of tall fescue varieties that are low-endophyte (certified to be less than 5 % infection) have improved animal performance expectations from tall fescue. Early releases of low-endophyte varieties were criticized for being low in vigor and yield ( e.g. Johnstone). This study indicates that yield does not have to be sacrificed with the selection of low-endophyte varieties. Several low-endophyte varieties, and infected Kentucky 31 had similar yield when data for the three years were statistically analyzed.
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