Abstract
Seed of Kentucky bluegrass (Poa pratensis L.) and perennial ryegrass (Lolium perenne L.) were added (5.5 kg each) to 1135 liters of water and 54.4 kg of wood fiber in a hydro-seeding unit that. used a centrifugal pump both to agitate (recirculate) the slurry and deliver it to the seedbed. Samples were collected after 0, 15, 30, 60, 90 and 120 minutes of agitation, the seed separated from the fiber and air-dried. The seed then were subjected to a germination test (15°/25°C, 16 h/8 h; darkness) and a slant test to determine primary root length at 14 days after planting. Increasing duration of agitation had no effect on germination percentage of Kentucky bluegrass (79% average) but slightly decreased germination of perennial ryegrass from 91% at 0 minutes to 82% after 120 minutes. Slurry agitation had slight effects on germination rate; Kentucky bluegrass was slowed slightly (less than 1 day) and perennial ryegrass was hastened slightly (maximum of 0.5 days). Primary root length of Kentucky bluegrass was decreased from 39 mm at 0 minutes to 28 mm after 120 minutes. Primary root growth of perennial ryegrass increased with up to 30 minutes of agitation, but showed no further growth between 30 and 120 minutes. We conclude that germination and seedling root length of both species were affected little by slurry agitation with a centrifugal pump for up to 120 minutes in an Easy Lawn Model HD 3503 hydroseeding system. The lemmas and paleas of the agitated seeds were intact and appeared undamaged. These accessory structures presumably protected the caryopses from possible agitation damage.