Persistence and growth of Lotononis bainesii–Digitaria decumbens pastures: 2. Sheep treading

Abstract

SUMMARYA pasture of Lotononis bainesii and Digitaria decumbens cv. Pangola at Mt Cotton, south-east Queensland was mown on six occasions at intervals of ca. 3 months and after each mowing was subjected in 1 day to the treading intensity expected from sheep grazing at 0, 7, 14, 21 and 28/ha. A movable corridor and folds were employed to walk the sheep the required number of times on eight replicates of each treatment.Lotononis regrowth was negatively related to sheep treading intensity, whereas Pangola was highly resistant to treading and grew vigorously from underground buds on rhizomes and from persisting stolons. Young lotononis seedlings were more vulnerable than older seedlings which had branched; plants developed from autonomous nodal roots were more resistant than seedlings. Attention is drawn to the contractile growth of the hypocotyl following epigeal germination which leads to a buried crown.Lotononis plants were short-lived, and seedling regeneration of ca. 27 and 47 plants/m2 occurred in the late summer of the 2nd and 3rd year after sowing. Soil seed reserves averaged 16900/m2. Studies might be undertaken of management systems directed to favouring lotononis plant replacement through accretion to seed reserves, seedling regeneration through the creation of ‘gaps’, and seedling survival through judicious timing of grazing.