Impact of Fertilizer Type, Seed Coating, and Duration of Exposure on the Germination of Orchardgrass Seed

Cool-season grasses such as orchardgrass, are important components of forage systems in transition zone states like Kentucky. To maintain dense and vigorous sods, improved cool-season grass varieties are sometimes overseeded into existing stands in late-winter or early-spring. In many cases seed is mixed with fertilizer and top-dressed onto pastures. Little data are available on the impact of fertilizer type or duration of exposure on the germination of raw and coated grass seed. The objective of this study was to evaluate the impact of two fertilizer types, muriate of potash and a blended fertilizer (urea, diammonium phosphate, and muriate of potash), and the duration of exposure (1 to 28 days) on the germination of an improved orchardgrass variety that was raw or coated. Mixing seed with the blended fertilizer resulted in a quadratic decrease in germination rate for the raw seed and coated seed. This rate of decrease was greater for the coated seed in the blended fertilizer. Combining seed with muriate of potash resulted in a linear decline in germination with the decline being similar for both the coated and raw seed. Overall, the rate of decrease was considerably less than that of the blended fertilizer. Results of this study indicate that the combination of seed coating and blended fertilizer had the most detrimental impact on orchardgrass germination