We\u2019ve written previously about the positive benefits of using volcanic basalt to speed the composting process. (See \u201cCharge up your compost pile with nutrient-rich volcanic rock dust<\/a><\/em>\u201d and \u201cAdd rock dust to compost to feed your plants a balanced diet<\/a><\/em>.\u201d)<\/p>\n Rock dust serves as food for the millions of beneficial microorganisms that feed on each other and help break down organic matter. More microbial activity means more heat, and more heat leads to faster and more efficient composting.<\/p>\n Rock dust isn\u2019t just a great complement to compost, however. It is also highly effective in helping improve soil\u2019s health and fertility when combined with biochar, a solid material rich in carbon that was used as a traditional soil amendment for thousands of years. Indeed, evidence of \u201cterra preta,\u201d or \u201cblack earth,\u201d dating back to the Pre-Columbian era, is still visible in the Brazilian Amazon.<\/p>\n Like rock dust, biochar has seen a recent resurgence as more people become aware of sustainability methods from the past\u2014and understand their role in our future. When used together, they help the remineralization process by ensuring that plants have a steady supply of essential minerals and nutrients.<\/p>\n It works like this: Rock dust weather slowly, releasing essential minerals and trace elements into the soil over time where they are readily accessible to plant roots when they need them. Biochar helps keep these important minerals from leaching away too quickly by acting like a sponge whose absorbent surfaces also provide a safe place where beneficial microbes multiply and thrive.<\/p>\n