The two experiments reported examined the effects of sheep treading on pasture growth and soil characteristics on autumn-irrigated subterranean clover-Wimmera ryegrass pastures and their subsequent influence on winter production. Treading only (experiment 1) increased the bulk density of soil by 40% as the stocking rate increased from 0 to 39.2 sheep ha-1. This caused a 33% reduction in late winter production (July), the decline (675 kg ha-1) being due mainly to a reduction in the proportion of ryegrass in the pasture. The combined impacts of treading and grazing (experiment 2) proved more detrimental to subsequent pasture recovery. At the July measurement, treading reduced production by 20% when the stocking rate was increased from 0 to 19.6 sheep ha-1, while the combined effect produced a 58% loss in yield. In addition to stocking rate, the length of the pre-grazing establishment period proved critical, with greater compaction evident in plots stocked 24 h after irrigation. This compaction affected the botanical composition, significantly more ryegrass being present in compacted plots, although increased tillering was encouraged by intense defoliation at high stocking rates which intensified this effect.

Between 1962 and 1964, 4 experiments were conducted at Leeton, New South Wales, Australia to examine the potential productivity of a range of irrigated winter forage crops in providing useful feed during the period of shortage in late autumn and early winter. In addition, the effects of sowing rate were examined for sowings using (a) prepared seedbeds or (b) sod-seeding into existing subterranean clover/Lolium rigidum cv. Wimmera pastures. DM yields at 74, 109, 144 or 173 days from sowing were compared with a subterranean clover/ryegrass control. Of the spp. evaluated the cereals were the most consistent both for initial production and subsequent regrowth. For the cruciferous spp. early cutting (100 days after sowing) proved detrimental to subsequent production, reducing the contribution of the sown spp. to 3% DM. Although the low proportion of the leguminous forages limited their potential production, they increased pasture quality relative to the clover/ryegrass control. DM production of wheat and rape increased with increasing sowing rate on (a) but for turnips there was a yield decline with increased sowing rate. Oats showed no response to sowing rate on (a), but increasing the sowing rate on (b) plots increased the proportion of oats in the pasture, although there was a consequent reduction in total yield. Increases in the contribution made by wheat to total yield as a result of increased sowing on (b) plots were small.