Forage production and nutritional quality at different development stages of black oat

The present study evaluated the agronomic productive and qualitative traits of black oat (Avena strigosa) forage harvested at different developmental stages for haylage production. This was a 2 x 3 factorial randomized complete block design consisting of six treatments, two stages of development of the crop (vegetative and full vegetative) associated with three harvest seasons, with four replications: T1 - vegetative stage, first cut, when light interception reached values between 90 and 95 %; T2 - vegetative stage with harvest seven days after the first cut; T3 - vegetative stage with harvest fourteen days after the first cut; T4 - full vegetative stage, second cut, when again the light interception reached values between 90 and 95 %; T5 - full vegetative stage with harvest seven days after the second cut; and T6 - full vegetative stage with harvest fourteen days after the second cut. The first cut at the vegetative stage of black oat generated a larger dry biomass production with 2.478 kg ha-1 and a greater participation of green leaves compared to the second cut at the full vegetative stage, as well as the in situ degradability of green leaves and the stem was higher in the first cut. The delay of 7 or 14 days from the ideal harvest time of the black oat forage reduced the nutritional quality. The first cut at the vegetative stage resulted in higher dry biomass production, greater participation of green leaves in the dry matter and better digestibility of green leaves and stem compared to the second cut at the full vegetative stage.