In the heart of Italy’s Po Valley, a groundbreaking study is challenging conventional wisdom about nitrogen fertilization in maize cultivation. Researchers from the University of Padua, led by agronomist Pranay Kumar Bolla, have demonstrated that a foliar-sprayed bio-fertilizer containing nitrogen-fixing bacteria can enhance maize growth and yield, potentially reducing the need for synthetic nitrogen inputs.
The study, published in the journal *Frontiers in Agricultural Science* (formerly Frontiers in Plant Science), focused on Methylobacterium symbioticum (MS), a plant growth-promoting bacterium that colonizes leaf surfaces. “We were intrigued by the potential of these bacteria to improve nitrogen use efficiency in maize,” Bolla explains. “Our goal was to see if we could enhance crop productivity while reducing the environmental footprint of nitrogen fertilization.”
The research team conducted an open-field trial in northeastern Italy, applying MS to maize plants under varying nitrogen fertilization rates. They found that MS significantly promoted aboveground growth and delayed leaf senescence, a phenomenon known as “stay-green.” This effect was likely due to the bacterium’s ACC-deaminase activity, which helps plants cope with stress and maintain chlorophyll levels.
One of the most striking findings was the impact of MS on root electrical capacitance, a measure of root vigor. “Under the N320 + MS treatment, we saw a 54% increase in root electrical capacitance compared to the control at flowering,” Bolla reports. “This suggests that MS can enhance root growth and function, which is crucial for nutrient and water uptake.”
The study also revealed that MS-treated plants had higher aboveground nitrogen accumulation and a non-significant increase in grain protein content. While yield responses were non-linear with respect to nitrogen dose, the N300 + MS treatment showed a 12% increase in yield compared to the control.
The implications of this research are significant for the agricultural sector, particularly in the context of sustainable intensification. By enhancing nitrogen use efficiency, MS could help farmers reduce their reliance on synthetic fertilizers, cutting costs and minimizing environmental impacts. “This microbial inoculation strategy presents an environmentally-friendly and sustainable approach to maize cultivation,” Bolla asserts.
Moreover, the study opens up new avenues for research into plant growth-promoting bacteria and their role in improving crop productivity. As the world grapples with the challenges of climate change and food security, such innovations could play a pivotal role in shaping the future of agriculture.
In the words of Bolla, “This is just the beginning. There’s so much more to explore in the realm of plant-microbe interactions and their potential to revolutionize agriculture.” With further research and development, MS and similar bio-fertilizers could become valuable tools in the quest for sustainable and productive farming systems.