The effect of management during spring on the growth of a mixed annual pasture containing capeweed (Arctotheca calendula)

Abstract

A number of grazing and mowing treatments were imposed in spring on a mixed annual pasture mainly comprising capeweed (Arctotheca calendula) 36 per cent and barley grass (Hordeum leporinum) 27 per cent, with a small amount of (4 per cent) subterranean clover (Trifolium subterraneum). The effects of treatments on flowering, seed setting and subsequent autumn production were followed, with special reference to any possible reduction in capeweed content. Seed numbers of all species were reduced by grazing throughout spring (barley grass was least affected) and by late mowing (severe reduction in the grasses), but early mowing had little effect. The mowing treatments all increased the content of capeweed and subterranean clover in the pasture next autumn and reduced the amount of grass, especially barley grass. Close grazing increased barley grass content and, if it continued throughout the spring, capeweed content also increased. Seed germination following rain in January varied considerably between treatments, but was not greater than 3 per cent on any. It was highest where dry pasture residues were present, and clover and capeweed seed germinated more than grass seed. It was concluded that spring management is unlikely to offer scope for reduction in capeweed content of pastures.