Growth Stimulation of Tropical Grass (<i>Megathyrsus maximus</i> Jacq.) by Humic Substances and <i>Herbaspirillum seropedicae</i>

This study aimed to evaluate the effect of soluble humic substances and plant-growth-promoting bacteria on the vegetative growth of Mombaça grass. A greenhouse experiment was conducted to study the effects of foliar applications of humic substances (0, 12, 24, 48, and 96 mg C L<sup>−1</sup&...

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Main Authors: Luciano P. Canellas, Natália A. Canellas, Rakiely M. Silva, Etelvino H. Novotny, Fabio L. Olivares
Format: Article
Language:English
Published: MDPI AG 2024-09-01
Series:Agronomy
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Online Access:https://www.mdpi.com/2073-4395/14/9/2006
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Summary:This study aimed to evaluate the effect of soluble humic substances and plant-growth-promoting bacteria on the vegetative growth of Mombaça grass. A greenhouse experiment was conducted to study the effects of foliar applications of humic substances (0, 12, 24, 48, and 96 mg C L<sup>−1</sup>) on the growth of Mombaça fifteen days after germination. After determining the optimal concentration range, a field trial was carried out in which humic substances at the best concentration were applied simultaneously with <i>Herbaspirillum seropedicae</i> strain UENF-H19 fifteen days after germination in three replicates. The best growth of Mombaça in the greenhouse was obtained with 48 mg C of the humic substance L<sup>−1</sup>, which promoted a shoot fresh weight 80% higher than in the control treatment. The increase was almost identical to that observed during the 50-week field experiment in plots treated with humic substances combined with <i>H. seropedicae</i>. The treated plants produced an 81% higher shoot fresh weight than the control, with no dry mass, nitrogen content, or crude protein change during the one-year evaluation period. Despite the efficiency of the selected microbial inoculants under controlled-environment experiments, the agronomical significance under field conditions remains a subject of debate and improvement. The present study demonstrates that combining <i>Herbaspirillum seropedicae</i> with humic substances (plural) could significantly increase pasture production under field conditions.
ISSN:2073-4395