Date of this Version
Guretzky, J.A.; Redfearn, D.D. Seeding Rate Effects on Forage Mass and Vegetation Dynamics of Cool-Season Grass Sod Interseeded with Sorghum-Sudangrass. Agronomy 2021, 11, 2449. https://doi.org/ 10.3390/agronomy11122449
Interseeding annual warm-season grasses into perennial cool-season grasses has the potential to increase summer forage mass and nutritive value. Knowledge of how seeding rate affects annual warm-season grass establishment, forage mass, and vegetation dynamics remains limited. From 2016–2017, we conducted a field experiment evaluating the effects of seeding rates on sorghum-sudangrass (Sorghum bicolor x S. bicolor var. sudanense) density and forage mass and on the frequency of occurrence of plant species in cool-season grass sod in Lincoln, NE. The experiment had a completely randomized design consisting of six replicates of four seeding rates [0, 14, 28, and 35 kg pure live seed (PLS) ha-1] in sod mowed at a 2.5-cm height and one unseeded, non-mowed control treatment. Sorghum-sudangrass establishment increased with seeding rate from an average of 20 to 45 plants m-2 as the seeding rate increased from 14 to 35 kg PLS ha-1. Forage mass depended on a seeding rate x harvest interaction, showing positive linear and cubic responses to seeding rate in consecutive harvests at 45 and 90 d after interseeding. To increase forage mass in perennial cool-season grass sod, producers should interseed sorghum-sudangrass with at least 28 kg PLS ha-1. One-time seedings into cool-season, perennial grass sod have no residual effects on subsequent forage mass and vegetation dynamics.