Bioformulation of biochar as a potential inoculant carrier for sustainable agriculture

The global population is steadily increasing, projected to reach 9.7 billion by 2050. This growth places immense pressure on food production, often leading to intensive agricultural practices that rely heavily on chemical fertilizers and pesticides. While these agrochemicals boost yields, they come at a significant environmental cost, contributing to soil degradation and posing potential risks to human health . The urgent need for sustainable alternatives has driven researchers to explore innovative solutions that can enhance crop growth without harming our planet.

One such promising alternative lies in the power of nature itself: Plant Growth-Promoting Rhizobacteria (PGPR). These beneficial soil microorganisms are known for their ability to support high-yield plants and improve various aspects of plant health, from disease resistance to nutrient uptake . However, simply introducing PGPR into the soil often faces challenges. Their viability can be compromised by the complex and heterogeneous soil environment, competition from native microbes, and fluctuating environmental conditions . This is where the concept of an "inoculant carrier" becomes crucial – a material that can protect and deliver these beneficial bacteria effectively to the plant roots .

Our research, published in Environmental Technology & Innovation, looks into the potential of biochar as an ideal inoculant carrier for PGPR. Biochar is a carbon-rich material produced from the thermal decomposition of biomass, such as agricultural, animal, and municipal wastes, under limited oxygen conditions . This process, known as pyrolysis, hydrothermal carbonization, gasification, or torrefaction, transforms waste into a valuable product . What makes biochar so effective? It possesses a highly porous structure, contains naturally derived nutrients, and exhibits excellent water and nutrient retention properties, all of which create a favorable microenvironment for microbial growth and survival . Furthermore, its physicochemical properties, including surface area and pore structure, can be modified through methods like chemical oxidation/reduction and physical activation to optimize the immobilization of PGPR .

The synergistic combination of biochar and PGPR offers a powerful tool for sustainable agriculture. By immobilizing PGPR onto biochar, we can significantly improve the bacteria's resistance to environmental stresses and protect them from soil microfauna . This bioformulation leads to enhanced plant growth, observed through higher chlorophyll content, increased nodulation, and improved nutrient uptake by crops . Studies have shown that biochar-based inoculants can even reduce plant diseases, such as tomato wilt caused by Fusarium sp. . Essentially, biochar acts as a protective home and a nutrient reservoir, enabling the PGPR to thrive and exert their beneficial effects, ultimately contributing to fewer environmental hazards and promoting agricultural sustainability.

This research highlights biochar's immense potential as a renewable and environmentally friendly biofertilizer, especially in challenging agricultural environments. By understanding the intricate interplay between biochar's properties and microbial activity, we can design more effective and standardized carriers for widespread application in the field.

To learn more about this research, or if you have any questions, please feel free to contact Dr. Aaronn Avit Ajeng at aaronnavit@um.edu.my or contact@um.edu.my.