In Indian farmland, chickpeas are not only an important protein source for the country’s vegetarian population but also account for 70% of the global total production. Driven by agricultural technological advancements and policies such as the national food security program, India’s chickpea production has surged from 7.3 million tons in 2014–2015 to 14 million tons in 2021–2022. However, this crop is facing a serious threat from Sclerotinia sclerotiorum-induced sclerotinia disease (commonly known as “white mold”). Under suitable temperature and humidity conditions, it can cause a yield reduction of over 50%. The pathogen survives long-term through sclerotia in the soil, making traditional control methods difficult to completely solve.
Biochar is a porous carbon material formed by the high-temperature pyrolysis of biomass under oxygen-deficient conditions. Its abundant pores provide a “shelter” for microorganisms, and its high carbon content supplies energy for beneficial bacteria. As a widely used biocontrol fungus, Trichoderma can inhibit pathogens by competing for nutrients and secreting antimicrobial substances, while also promoting plant root development. Can biochar serve as a high-quality carrier for Trichoderma to inhibit Sclerotinia sclerotiorum while promoting crop growth?
A study published in Frontiers of Agricultural Science and Engineering (DOI: 10.15302/J-FASE-2024598) by Vipul Kumar from Lovely Professional University, India, and Rachid Lahlali from the National School of Agriculture of Meknès, Morocco, provides an answer to this question.
This study selected three common biomasses—hardwood, kitchen waste, and wheat straw—to prepare biochar, systematically compared their physicochemical properties (such as carbon-nitrogen content and pore structure), and observed the growth of Trichoderma on biochar and its inhibitory effect on Sclerotinia sclerotiorum by combining different concentrations and particle sizes. Field trials further verified the actual impact of these combinations on chickpea growth and disease.
The results showed that hardwood biochar performed excellently in multiple key indicators: it had the highest lignin and cellulose content, and its formed pore structure was more conducive to Trichoderma colonization; after 6 weeks, the number of Trichoderma on hardwood biochar reached 33.5×10⁵ CFU·g^-1, significantly higher than other types of biochar. More critically, the combination of hardwood biochar and Trichoderma exhibited a “dual effect”—it not only inhibited the growth of Sclerotinia sclerotiorum but also promoted chickpea root development, while reducing disease severity by 36.5%.
This is equivalent to creating a “livable community” for Trichoderma, enabling beneficial bacteria to more efficiently combat pathogens while improving the soil environment. Researchers noted that hardwood biochar is not only a “carrier” for Trichoderma; its inherent alkalinity and porous properties can directly inhibit the survival of Sclerotinia sclerotiorum, and the proliferation of Trichoderma further enhances this inhibitory effect. Field data showed that the treatment group applying hardwood biochar + Trichoderma had significantly increased phenolic substance content in chickpea leaves, indicating that the plants' own disease resistance was also activated.
This study clarifies the optimal parameters for biochar as a biocontrol fungus carrier: hardwood source, 4% addition concentration, and 150-µm particle size. This provides an operable technical solution for practical agricultural applications, holding promise to reduce chemical pesticide use while improving chickpea yield and quality.
DOI: 10.15302/J-FASE-2024598