Optimizing small grain forage yield, nutrient composition, and economics via strategic harvest timing

The impact of harvest timing on forage yield, nutritional composition, regrowth potential, and economic return was assessed for three awnless forage barley (Hordeum vulgare L.) (Hays, Haybet, Lavina) and oat (Avena sativa L.) varieties (Monida, Otana, Ajay) at four phenological stages (boot, heading, milk, or soft-dough) across three site years at two locations in southern Idaho, United States (Aberdeen 2021–2022, Rexburg 2021). Within a harvest timing, forage barley and oat generally had similar yield and forage nutrient compositions. At each location, forage mass increased with delayed harvests and, averaged across all varieties, yielded 9.35, 1.96, and 7.32 Mg ha⁻¹ at Aberdeen 2021, Aberdeen 2022, and Rexburg 2021, respectively, when harvested at the soft dough stage. It was unprofitable to harvest the crops at the boot or heading stages due to insufficient forage mass production. Forage nutrient composition was greatest when harvested at the boot stage producing a “premium” quality hay (crude protein >13%). Barley and oats harvested after the boot stage had poorer forage nutrient composition but were generally still classified as good quality hays (crude protein between 9% and 13%) suitable for beef/cow-calf operations (Bos taurus), dairy heifers (18–24 months), and non-lactating cows. Oat (excluding Ajay) and some barley varieties regrew after harvest at the boot or heading stage, but double harvests were typically not as profitable as a single harvest done at soft dough. This study recommends that irrigated forage barley and oats should be harvested at the soft dough stage to maximize yield and profitability.