Black Oat Production in Different Oversowing Modalities in Integrated Crop-Livestock System

The aim of this study was to evaluate the effects of corn (Zea mays L.) silage intercropped with palisade grass [Urochloa brizantha (Hochst. ex A. Rich.) R. Webster cv. Marandu] and pigeonpea [Cajanus cajan (L.) Millsp.] in summer/fall and oversowing modalities of black oat (Avena strigosa Schreb.) in winter/spring on forage mass of pasture. The experiment was conducted in a completely randomized design, with a 2×2×2 factorial treatment arrangement (n = 48/yr), combining two silage production systems (SPS): corn+palisade grass+pigeonpea (C+PG+PP) and corn+palisade grass (C+PG); two black oat oversowing modalities (BO): in line (LI) and broadcasted (BR); and two grazing cycles (GC). Grazing management, it were used 12 crossbred male lambs [BW = 27.2 ± 0.6 and 24.0 ± 0.7 kg, first and second growing season, respectively] by treatment. Animals spent the day grazing in the black oat (fixed stocking rate and rotational grazing) and in the night, they were herded into a barn. Prior to starting grazing, sixteen height measurements, using a sward stick were determined, and forage mass of pasture (FM) was determined, by cutting two representative samples (0.25 m² areas per plot at ground level). Forage samples were dried, weighed, and reported as kg of DM/ha. Data were analyzed using PROC MIXED with SPS, BO, GC and their interactions were considered as fixed effects. Paddocks (SPS×BO×GC) as random effects. In the first growing season, FM was greater for C+PG+PP (P=0.04, 814 vs. 665 kg of DM/ha), black oat oversowing LI (P=0.05, 813 vs. 667 kg of DM/ha) and in the first GC (P<0.001, 884 vs. 635 kg of DM/ha). In the second growing season, there were interactions between SPS×BO. Thus, greater FM was observed for C+PG+PP associated with LI oversowing of oat than BR (P=0.04, 2409 vs. 1947 kg of DM/ha) in this season. However, for C+PG, the FM was not altered, regardless of oat oversowing, BR or LI (P=0.04, 1803 vs. 1706 kg of DM/ha). For oversowing BR, the FM was not altered, regardless of silage production systems, C+PG+PP or C+PG (P=0.04, 1947 vs. 1804 kg of DM/ha). For LI oversowing, the FM was greater to C+PG+PP (P=0.04, 2409 vs. 1707 kg of DM/ha). In conclusion, corn intercropped with palisade grass and pigeonpea for silage in summer/fall increases the forage mass of pasture. In the winter/spring in line oversowing of black oat presents greater forage mass, than the broadcasted modality.