Seedling Establishment and Forage Accumulation of ‘Ceres Tonic’ Plantain in Pure Stands and in Grass Mixtures

The evaluated species were plantain 'Ceres Tonic' (PL), annual ryegrass 'Jeanne' (RG), tall fescue (Festuca arundinacea Schreb.) 'Enforcer' (TF), and orchard grass (D. glomerata L.) 'Oasis' (OG). The trial was carried out in an area with soil apt for agriculture (typical Argiudol) with 4.6% OM and pH 5.5. Sowing was done on 4 April in 1.4 × 5 m plots and 17.5 cm between rows. Plots were allocated in a randomized complete block design (n = 3) in a factorial arrangement of four pastures (PL pure, PL+RG, PL+TF, PL+OG), and three PL sowing densities. Plantain sowing densities were 4, 8, and 12 kg seed ha-1 in pure PL plots, and 50% of these values in the mixtures (low = LD, medium = MD, and high = HD densities). Medium density is empirically recommended for this species in mixtures in the region. Grass mixture sowing densities were 30, 15, and 6 kg seed ha-1 for RG, TF, and OG, respectively. These densities are also usually suggested to achieve adequate plant densities in the first year. By considering theapplied densities and a sowing efficiency of 45%, it is possible to obtain approximately 250 pl m2. Seed germinability of the four species was 89, 96, 94, and 78% for PL, RG, TF, and OG, respectively. The trial area was fertilized before sowing with a dose equivalent to 70 kg ha-1 of diammonium phosphate. After sowing, but before seedling emergence, a dose of glyphosate, equivalent to 2 L ha-1, was applied for weed control. Plots were irrigated twice with 10 mm water before seedling emergence and 15 d after sowing because of a moisture deficit. Plantain sowing density did not interact with pasture type for plant density 2 mo after sowing, but both factors affected it (Figure 1). Total plant density was 35% higher in PL+RG and PL+TF than in PL+OG and PL plots (216 ± 58 vs. 161 ± 37 pl m-2). Grass plant density differed among mixtures and, on the average, OG was 65% lower than RG and TF (RG = 183 ± 19, TF = 171 ± 18, and OG = 107 ± 19 pl m-2). This affected plantain seedling establishment (p < 0.001), for which plant density in the PL+RG plots was only 26% of the pure plantain plot density (27 ± 3 vs. 149 ± 12 pl m-2). In the PL+TF and PL+OG plots, density was 35% (54 ± 4 vs.149 ± 12 pl m-2) of pure plantain stand density. The relative plant size of the four species in the MD plots is shown in Figure 2. The seasonal forage accumulation pattern differed among pastures (season × pasture type interaction < 0.001), and increased in all of them when plantain sowing