PS11-21. Impact of Delayed Planting on Yield of Cool-Season Annual Pastures.

Abstract Late-fall drought often delays the establishment of cool-season annual forages in the southeastern United States, leading to planting beyond the recommended window and increased uncertainty about forage production. This study evaluated the impact of delayed planting dates on the yield of cool-season annual mixtures and identified mixtures that performed better under late planting. A small-plot field experiment was conducted at the Gulf Coast Research and Extension Center in Fairhope, Alabama, within an existing bahiagrass pasture using a no-till drill. Treatments were arranged in a randomized complete block design with four replications. Planting dates included October 15, November 5, December 2, December 15, and January 5, which corresponded to 30, 51, 78, 91, and 112 days after the Extension-recommended planting date of September 15. Four cool-season annual mixtures were assessed: wheat + oat + crimson clover; wheat + oat + crimson clover + annual ryegrass; rye + oat + crimson clover; and rye + oat + crimson clover + annual ryegrass. Forage was harvested monthly beginning in January using a forage harvester set to a 10-cm stubble height. As hypothesized, there was an effect of planting delay (P < 0.01), month of harvest (P < 0.01), and their interaction (P < 0.01) on dry matter yield (DMY). Delayed planting resulted in a DMY loss of 16.7 kg ha-1 d-1 by January and 20.6 kg ha-1 d-1 by February, but recovery of yield loss was seen by March (-5.7 kg ha-1 d-1). However, all forage mixtures responded similarly to delayed planting (P = 0.50). Results are interpreted to mean that late planting can substantially reduce early-season forage production potential, thereby affecting seasonal forage availability in beef production systems.