Some research shows soil fertility and quality are improved with the addition of biochar, which is a type of charcoal made from biomass—plant or plant-based material such as grass clippings or wood chips—burned in little to no oxygen.
- As well as altering the physical and chemical properties of the soil around the rhizosphere, biochar also alters the biological dynamics of a soil through several mechanisms.
- Biochar is initially sterile and therefore has no indigenous populations of microorganisms. Instead, the physical structure of the biochar encourages colonization by various arbuscular mycorrhizal fungi, nematodes and bacteria.
- Biochar absorbs humic acid, which is used as sustenance by soil microbes, and humic acid absorbs fertilizers, preventing them from leaching out of the soil. Roots can access this stored fertilizer.
- A number of plant-enhancing microorganisms, such as Trichoderma, are boosted in soils amended with biochar.
- Trichoderma plays a role in eliciting a benefit known as systemic-induced resistance, which can result in the increase in defense mechanisms within the plant that prevents damage from insect pests and disease.
- Studies have shown a significant interaction between biochar and Fusarium oxysporum that strongly reduces disease severity.