Emergency seeding of cool-season annuals into perennial grass after fall drought

摘要

Spring establishment of cool-season annual grasses into poorly producing orchardgrass (Dactylis glomerata L) (OG) swards may improve forage production and nutritive value in the southeastern United States following a fall drought. A randomized complete block experiment was conducted where annual ryegrass (Lolium multiflorum Lam.) (AR) or forage oat (Avena sativa L.) (FO) was interseeded into an existing OG stand over three seeding dates with (+) or without (–) a burndown herbicide (BD) treatment andcompared with an OG monoculture (control). In 2017, after a warm and wet winter, the OG monoculture (control) was able to produce sufficient forage mass (FM) without significant reduction in nutritive value as compared with OG interseeded with AR or FO.In 2018, OG had approximately 2,600 lb acre–1 less FM than in 2017, suggesting that recurrent fall drought with unfavorable winter conditions resulted in long-term damage to the perennial sward. Meanwhile, treatments without BD did not show higher FM in the beginning of the season. Burndown treatment in general increased FM and nutritive value. An economic analysis of the study also revealed results suggesting that interseeding AR and FO in the spring is not economically viable, as it may cost up to 10 times as much as the control.