Humic acid can enhance soil carbon content by stimulating plant growth and microbial activity. Humic substances promote more root exudates and fine roots, which, along with microbial decomposition, contribute carbon to the soil. When combined with manure, it’s important to manage the carbon-to-nitrogen ratio carefully. If the ratio is too low, microbes may deplete the soil’s carbon. Using humic substances helps ensure a more reliable increase in soil carbon, especially with proper tillage practices.

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