What is the use of biochar in farming ? 1. Biochar can be used as a part of the growing medium in vertical farming. 2. When biochar is a part of the growing medium, it promotes the growth of nitrogen-fixing microorganisms. 3. When biochar is a part of the growing medium, it enables the growing medium to retain water for longer time. Which of the statements given above is/are correct ?

Option (d) is correct because biochar’s high porosity and large surface area allow it to serve as a lightweight substrate for vertical farming, a protective habitat for nitrogen-fixing bacteria, and a reservoir for moisture retention. While some might overlook its biological benefits (making option 'c' tempting), biochar significantly enhances soil health by providing a stable, carbon-rich environment that fosters microbial colonization. The core concept tested is the physical and chemical properties of biochar and its multi-functional applications in sustainable agriculture.