Current agriculture intensifies crop cultivation to meet food demand, leading to unsustainable use of chemical fertilizers. This study investigates a few physiological and agronomic responses of common wheat following the inoculation with plant growth-promoting bacteria to reduce nitrogen inputs. A field trial was conducted in 2022–2023, in Legnago (Verona, Italy) on Triticum aestivum var. LG-Auriga comparing full (180 kg ha⁻¹) and reduced (130 kg ha⁻¹) N doses, both with and without foliar application at end tillering of the N-fixing bacterium Methylobacterium symbioticum. Biofertilization did not improve shoot growth, while it seldom increased the root length density in the arable layer. It delayed leaf senescence, prolonged photosynthetic activity, and amplified stomatal conductance and PSII efficiency under the reduced N dose. Appreciable ACC-deaminase activity of such bacterium disclosed augmented nitrogen retrieval and reduced ethylene production, explaining the ameliorated stay-green. Yield and test weight were unaffected by biofertilization, while both glutenin-to-gliadin and HMW-to-LMW ratios increased together with dough tenacity. It is concluded that Methylobacterium symbioticum can amplify nitrogen metabolism at a reduced nitrogen dose, offering a viable approach to reduce chemical fertilization under suboptimal growing conditions for achieving a more sustainable agriculture. Further research over multiple growing seasons and soil types is necessary to corroborate these preliminary observations.

Nitrogen (N) fertilization remains a critical challenge in sustainable agriculture. Plant growth-promoting bacteria offer a promising strategy to enhance nitrogen use efficiency and improve cereal crop productivity while reducing reliance on synthetic inputs. This open-field study evaluated the morpho-physiological effects of foliar application of Methylobacterium symbioticum (MS) on maize in NE Italy. Following a baseline application of liquid digestate (300 kg N ha^-¹) to all plots, four treatments were compared: N300 (digestate only, serving as the control); N300 + MS (digestate with MS); N350 (digestate with 50 kg ha^-¹ chemical N); and N320 + MS (digestate with 20 kg ha^-¹ chemical N and MS). ESEM imaging confirmed colonization of leaf surfaces by M. symbioticum. Its application significantly promoted aboveground growth and delayed leaf senescence by improving chlorophyll retention, increasing seasonal average SPAD from 46.9 in control to 49.4 (+5.3%, N300 + MS) and 48.8 (+4.1%, N320 + MS), likely mediated by the ascertained ACC-deaminase activity of MS. Root electrical capacitance showed treatment-specific effects, with the highest readings under the N320 + MS treatment (+54% vs. control at flowering). Yield responses were non-linear with respect to N dose, with N300 + MS showing a 12% (1,364 g/m²) and N320 + MS a 6% non-significant increase vs. control. MS-treated plants also exhibited a non-significant 5% increase in grain protein content, but significantly higher aboveground N accumulation. It is concluded that, this microbial inoculation strategy can enhance N use efficiency, particularly under reduced synthetic fertilization, presenting an environmentally-friendly and sustainable agricultural strategy for maize cultivation.

Conventional spring sowing of sugar beet in Europe faces increasing constraints from summer drought, high temperatures, and Cercospora beticola pressure due to climate change. This two-year field trial (2021–2022 and 2022–2023) evaluated the feasibility of autumn-sown sugar beet at a northern Mediterranean site in Legnaro (Padua, NE Italy, 45°21′ N). Nine varieties were assessed across four sowing dates in 2021 (late September to early November) and two sowing dates in 2022 (late September and late October). Measurements included overwinter survival, bolting incidence at two reproductive stages, fresh root and above-ground biomass yield at sequential harvest dates, and root soluble solids (°Brix). Post-winter mortality was negligible following September and early-October sowings, moderate after late-October sowings (17.3% in 2021; 13.2% in 2022), and extremely high after early-November sowing (81.5%). These patterns indicated that winter survival was more strongly determined by crop developmental stage before winter than by seasonal minimal temperatures recorded in two seasons (−3.6 °C and −6.3 °C, respectively). Bolting incidence showed the opposite trend, reaching near-complete or complete expression in the earliest sowings regardless of variety choice. In late-October sowings, clear varietal differences emerged. Some varieties combined low bolting incidence with high root yields, reaching 81.1–84.4 t ha⁻¹ at the final harvest (early August 2023). Root juice soluble solids were higher in the drier 2021–2022 season (exceeding 20 °Brix in several cases) than in the wetter 2022–2023 season (consistently below 17.5 °Brix), reflecting dilution effects associated with the different seasonal precipitation. In the sequential harvest series of late-October 2022 sowing, later harvest dates were generally associated with lower soluble solids. These results indicate that, within the autumn sowing window evaluated, late-October sowing combined with appropriate varietal selection provided the best balance between overwinter survival, bolting incidence, and root yield at this northern Mediterranean latitude. Future multi-site studies, including spring-sown controls, could enable direct comparison with conventional sowing practice.