PSVII-12 Effect of planting method on forage production of annual ryegrass and stocker performance

摘要

Different planting methods are alternatives for early grazing and/or extend the grazing season of winter pastures. The objective was to evaluate different planting methods on forage and animal performance. In three consecutive years, ryegrass cv. ‘Marshall’ was conventionally planted (33 kg seed/ha), and no-till and broadcast planted on a bermudagrass stand on nine 1.33 ha pastures (3 replicates/treatment). Urea was split applied at a rate of 40 units of N/ha on d 40 after planting and on d 40 after grazing started. Each pasture was continually stocked with five steers (245 ± 12 kg initial BW). Grazing started when ryegrass was at least 25 cm tall and 1,600 kg DM/ha. In the conventional planted pastures, steers were moved out (to a ryegrass pasture) when ground was too soft, returning to experimental pastures when grazing conditions were appropriate. Forage production was greater (P < 0.05) for conventional and no-till (2,800 and 2,389 kg DM/ha) than for broadcast pastures (1,770 kg DM/ha). Planting method and yr affected (P < 0.03) start of grazing. Conventional and no-till planting started 51 and 49 d earlier than broadcasted. In 2 yr, rainfall delayed by 17 d the start of grazing in the conventional planted pastures. Grazing days was greater (P < 0.01) for no-till (95 d) than conventional and broadcast planting (61 and 49 d, respectively). While on experimental pastures, ADG was similar (P = 0.08) between treatments. Due to the difference in grazing days, production per ha was greater (P < 0.01) for no-till (450 kg/ha) than for broadcast and conventional (199 and 241 kg/ha, respectively). No-tilled pastures offered better grazing environment while broadcast pastures had the disadvantages of slow germination and less forage production. Greater number of grazing days on no-tilled pastures allowed for better animal performance and dilution of input costs.