The influence of sowing method on perennial grass establishment. III. Survival and growth of emerged seedlings

Abstract

'Demeter' tall fescue (Festuca arundinacea Schreb.) and 'Victorian' perennial ryegrass (Lolium perenne L.) were sown separately into a white clover (Trifolium repens L.) dominant pasture in June 198 1. Eight sowing methods were compared to assess the survival and growth of perennial grasses sown by direct drill sowing methods relative to conventional seedbed and aerial sowing methods. Within direct drill treatments, two drill implements were factorially combined with three herbicide treatments. Sown seedling density decline was approximately linear from the maximum emerged density at 50 days after sowing to the established plant density at 250 days. Established ryegrass density ranged from 104.9 plants m-2 in the cultivated seedbed to 30.0 plants m-2 in the aerial plus herbicide method. Established plant density of fescue in the direct drill sowings was higher for the plus herbicide treatments (56.6-61.6 plants m-2) compared with the minus herbicide treatments (0-6.6 plants m-2). Seedling growth was severely reduced when seeds were direct drilled into unsprayed vegetation. Fescue seedlings in these treatments had failed to develop tillers by 250 days. The distribution of an index of individual seedling size was highly skewed towards smaller seedlings in the direct drill minus herbicide treatments indicating a high level of stress in these treatments. Competition from the unsprayed resident sward was intense and occurred at a very early stage in seedling development. Promotion of rapid early seedling growth through cultivation or herbicides enhanced survival of sown perennial grasses.