Mechanical defoliation as a management tool for kyllinga (Cyperus brevifolius) in irrigated pasture
F.L.F. HenskensA, Agriculture Victoria, Institute for Sustainable Irrigated Agriculture, RMB 3010, Kyabram, Victoria 3630, Australia.
A Present address: Institute for Integrated Agricultural Development, Agriculture Victoria, RMB 1145, Rutherglen, Victoria 3685, Australia.
Kyllinga is a weed of increasing importance in irrigated pastures throughout northern Victoria and in southern New South Wales. It is unpalatable and stock avoid otherwise productive swards where it is present. Farmers commonly mow paddocks after grazing to reduce competition from ungrazed plants. Mown paddocks are subsequently irrigated, which may facilitate kyllinga seed dispersal. This paper reports on the impact of defoliation on kyllinga growth and seed production under controlled conditions and the effect of seed age, periods of desiccation and immersion in water on germination. Defoliation reduced the DM of whole plants, plant parts and the number of seedheads at successive harvests, but not cumulative seedhead production. Plants cut every six weeks to a height of 30 mm produced around 40% more seedheads than uncut plants. Germination was low in seed 0-18 days old, but rose with increasing seed age. Seed germinated in water. Consequently, irrigation water is a viable vector for kyllinga. Frequent mowing may provide a means of suppressing kyllinga infestations while ensuring that only a small proportion of seeds produced are capable of germinating.
Plant Protection Quarterly (1998) 13 (3) 131-135.