CM were added to the inoculants before seed inoculation.
The factors consisted of three doses of nitrogen (zero, half and full dose); seed inoculation with A. brasilense (without inoculant, liquid inoculant and peat inoculant); two doses of bioregulator (0 and 250 mL ha−1) in two growing seasons (2010 and 2011).
Still in Luiz Eduardo Magalhães, inoculation in-furrow (T10) was significantly superior to treatments with foliar spray inoculation (T8, T9) and seed inoculation with a single inoculant dose receiving full N fertilization (T4) (Fig. 1B).
Inoculation methods: CONTROL (non-inoculated); SEED (standard seed inoculation); SOIL (soil spray inoculation at the V2.5 stage); FOLIAR (leaf spray inoculation at the V2.5 stage); FURROW (inoculation in the planting furrow at sowing).
Inoculation by soil spray with one dose of inoculant in addition to full N fertilization (T16) significantly increased plant height (PH) relative to all treatments with seed inoculation and to the non-inoculated control that received 75%% N (Table 4).
The experiments consisted of five treatments: (1) non-inoculated control (NI); (2) seed inoculation (SI) with Azospirillum at sowing; (3) SI + metabolites enriched with LCOs applied at sowing; (4) leaf spray inoculation (LSI) with Azospirillum strains at V3 stage; (5) LSI + enriched metabolites at the V3 stage.
ns not significant C non-inoculated control, SI standard seed inoculation, IPF inoculation at planting in the furrow, ILS inoculation by leaf spray at the V2.5 stage, ISS inoculation by soil spray at the V2.5 stage aN: 75%90(90 kg ha−1) and 100%% (120 kg ha−1), split in equal amounts every 8 days bInoculant dose:1× (1.0 × 105 cells seeds−1 or 1.0 × 105 cells plant−1).
Root growth, as indicated by root volume (RV), responded positively to seed inoculation (SI) with 2.5 doses of inoculant and full N fertilization (T6) when compared to all treatments of inoculation in-furrow (T7 T10).
Seed inoculation resulted in increased grain yield relative to the non-inoculated control, but no further increases were observed when metabolites were added; in contrast, leaf spray inoculation only resulted in yield increases when supplemented with enriched metabolites (Table 4).
The first method consisted of seed inoculation at sowing and the second of leaf spray with the same inoculant at the V3 stage (third leave developed).
Our results have identified alternative methods of inoculation that were as effective as the standard seed inoculation that may represent an important strategy to avoid the incompatibility between inoculant bacteria and pesticides employed for seed treatment.
