Inoculation with plant growth-promoting bacteria mitigates the negative impacts of global warming on nutrient absorption, efficiency, and forage productivity under field conditions.

Authors

João Vitor Silva E Silva, Renato de Mello Prado, Kamilla Silva Oliveira, Eduardo Habermann, Carlos Alberto Martinez, Dilier Olivera-Viciedo, Marcos Gervasio Pereira

Published in

Plant physiology and biochemistry : PPB. Volume 238. Pages 111573. Jul 24, 2026. Epub Jul 24, 2026.

Abstract

In tropical regions, forage grasses are predominantly cultivated under rainfed conditions, where prolonged warming may impair plant nutrition, metabolism, and productivity. Although co-inoculation with Azospirillum brasilense and Pseudomonas fluorescens has been proposed as a strategy to mitigate warming stress, its effects on forage nutritional responses, soluble C-N metabolites, and soil carbon-associated fractions under long-term field conditions remain insufficiently understood. To address this gap, a field experiment was conducted in Brazil using the hybrid Urochloa brizantha × Urochloa ruziziensis cv. Mavuno in a 2 × 2 factorial design, combining two temperature conditions, ambient and elevated (+2 °C above ambient), imposed by a T-FACE system, and two inoculation treatments, with and without co-inoculation. Nutritional parameters, dry matter production, total free amino acids, proline, total soluble sugars, sucrose and soil carbon-associated fractions were evaluated across four growth cycles: autumn, winter, and spring of 2023, and summer of 2024. Under non-inoculated conditions, prolonged warming affected nutrient-use efficiency more consistently than nutrient absorption, with negative effects becoming more evident in the later growth cycles, especially for N, P, and K. Warming also altered soluble C-N metabolism, mainly affecting total free amino acids and total soluble sugars, whereas sucrose and proline showed less consistent responses across cycles. Dry matter production was maintained under warming during the less restrictive phases of the experiment, whereas biomass reductions became more evident in the later cycles. Co-inoculation increased the absorption of N, P, K, and Si, especially in the later growth cycles, and partially mitigated the adverse effects of warming on plant nutritional resilience. In addition, co-inoculation modulated the accumulation of total free amino acids and total soluble sugars under both temperatures, indicating adjustments in primary C and N metabolism in specific cycles rather than a uniform accumulation of warming-related metabolites. Warming was also associated with changes in soil carbon fractions, whereas inoculation was associated with higher carbon contents in the humic acid and humin fractions at the end of the experiment. Overall, prolonged warming reduced the nutritional and metabolic resilience of rainfed tropical pasture over time, while co-inoculation contributed to improving nutrient acquisition, adjusting soluble C-N metabolism, and supporting the maintenance of soil carbon content under field conditions.

PMID:
42531618
Bibliographic data and abstract were imported from PubMed on 31 Jul 2026.

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