Effects of biochar amendment on wheat production, mycorrhizal status, soil microbial community, and properties of an Andisol in Southern Chile

Biochar (BC) production from agroforestry wastes and mycorrhizal fungi are potentially important agricultural practices for improving crops yields and increasing phosphorus (P) in volcanic soils. This study aimed to test the effect of BC application on wheat biomass and grain yield production, indigenous arbuscular mycorrhizal (AM) fungi propagules and soil microbial community and related to soil quality properties of an Andisol in Southern Chile. Biochars (BCs) were produced from oat hulls (OBC) and pine bark (PBC). Doses of 0, 5, 10, and 20 Mg ha-1 of BCs were applied on soil using wheat as the test crop. Wheat biomass (root and shoot portion) and grain yield, AM root colonization, spore, mycelium density, and glomalin content (glomalin related soil protein, EE-GRSP) were measured and related with soil quality properties such as bulk density, water-stable aggregates (WSA), and water holding capacity (WHC). The OBC had a significantly higher macronutrients content (N, P, K) than PBC. The highest dose of both BCs significantly improved shoot and root biomass and wheat grain yield. Application of 20 Mg ha-1 of OBC and PBC increased AM spore density and root colonization relative to control treatment. In the same way, the BC application significantly affects the AM mycelium density. The results showed that the application of higher BC dose changed the soil microbial community. The use of BCs in this volcanic soil is an effective strategy to increase wheat biomass, increase grain yield production, stimulate the indigenous AM fungi activity, enhance soil quality properties, and increase the sustainability levels of agricultural systems.