NATURAL RESEEDING IN PERENNIAL RYEGRASS/WHITE CLOVER DAIRY PASTURES

Abstract

The extent to which propagation of perennial ryegrass from seed can contribute to sward stability and the influence on this of spring pasture management (seedling competition and seed viability and losses was examined in a replicated plot experiment. Under hard grazing in late spring less than 5% of reproductive tillers reached flowering. Where grazing was restricted during reproductive tiller development to allow reseeding, 80-90% of tillers flowered. Subsequent seedling densities were 20-50 times higher and herbage accumulation during late summer-early winter was 33% greater on plots reseeded than those hard grazed in spring. Farm practices such as hard grazing, topping and possibly silage conservation which remove reproductive tillers before flowering will greatly reduce ryegrass reseeding and may contribute to the poor persistence of ryegrass swards under intensive dairy cattle grazing. Keywords: grassland management, propagation, botanical composition, herbage accumulation, soil, seed dynamics.