Interseeding annual warm‐season grasses into temperate pasturelands: Forage accumulation and composition

Interseeding annual warm‐season grasses into pastureland dominated by perennial cool‐season grasses may be a strategy to reduce shortage of forage. Field trials were conducted at three Nebraska (Mead, North Platte, and Sidney) and two Kansas (Hays and Mound Valley) locations in 2015–2016 (10 environments) to evaluate forage production responses to six interseeded annual warm‐season grass—corn (Zea mays L.), forage sorghum (Sorghum bicolor [L.] Moench), pearl millet (Pennisetum glaucum [L.] R. Br.), sudangrass (S. bicolor [L.] Moench ssp. drummondii [Nees ex Steud.] de Wet & Harlan), a sorghum–sudangrass hybrid (S. bicolor × S. bicolor var. sudanense), and an unseeded control—and two harvest frequency (once at 90 d and twice at 45 and 90 d after interseeding) treatments. Across environments, total forage accumulation was 146–214% and 100–102% greater in sudangrass and sorghum–sudangrass interseeded than unseeded pastures when harvested once and twice after interseeding, respectively. In smooth bromegrass (Bromus inermis Leyss.) pastures, interseeding sudangrass and sorghum–sudangrass increased forage accumulation in both years at Mead but in only one year at North Platte. In tall fescue (Lolium arundinaceum [Schreb.] Darbysh.) pastures, interseeding forage sorghum and sorghum–sudangrass increased forage accumulation by 103–211% relative to unseeded pastures. Interseeding annual warm‐season grasses presents an effective strategy to increase forage accumulation in humid pasturelands harvested once or twice after interseeding (Mead and Mound Valley). In semiarid pasturelands, forage responses to interseeding will vary from year‐to‐year depending on timing and amount of precipitation, but forage accumulation can be significant.