Forage yield and composition of Avena strigosa Schreb at different harvesting frecuencies and intensities
Harvesting frequency and intensity are management criteria in forage plants and their choices affect herbage yield and quality. The objectives of the study were to evaluate herbage yields of morphological components and chemical composition (crude protein, neutral detergent fiber and acid detergent fiber) of Saia oats (Avena strigosa Schreb) at three harvest frequencies (40, 50 and 60 cm sward height) and three harvest intensities (8, 14 and 20 cm residual foliage). The design was completely randomized with a factorial arrangement (3 × 3) of treatments and four replications. The factors were sward height (AD) and harvest intensity (IC). The experimental units were 36 plots of 12 m². Forage yield increased linearly (p = 0.007) with the increase in sward height (35 kg DM cm-1, R² = 0.91). Leaf blade yield decreased (-33 kg DM cm-1, R² = 0.99, p = 0.001) and pseudo stem plus stem yield increased (46 kg DM cm-1, R² = 0.98, p = 0.001) with increasing sward height. Harvest intensity did not affect foliage yield (p > 0.05); however, leaf blade yield was higher at high harvest intensity (8 cm residual herbage, p < 0.05). Crude protein (CP) showed linear decrease (p = 0.001) as sward height increased (-0.22 % cm-1, R² = 0.99), and neutral detergent fibre (NDF) was higher (51.2 %) at 60-14 and lower (41.9 %) at 40-8. Forage with higher proportion of leaf blades and lower NDF content was harvested at 40 cm sward height, in combination with moderate harvest intensities (8 and 14 cm residual foliage height).