Abstract
Humic substances (HS) are an indicator of fertile soils, but more and more soils keep losing there humic matter. This is mostly due to anthropogenic over-cultivation. Artificial humic acid (A-HA) and artificial fulvic acid were synthesized from agricultural litter, with high similarity to natural HS extracted from soil. These samples were added to black soils, and soil activity and nutrients availability were analyzed. The results demonstrate that the content of dissolved organic matter and total organic carbon (TOC) largely increased. The increase in TOC 28 days after addition of A-HA was 21.4 g/kg. This was much higher than the amount of the added A-HA carbon, which was 0.3 g/kg. As a "secondary" benefit, nutrient availability is increased, promoting the growth of plants. Using high-throughput sequencing we revealed that A-HA strongly supports the growth of photosynthetic Rubrivivax gelatinosus, which induced the carbon sequestration. Thus, application of artificial HS shows potential for biologically amplified carbon sequestration within black soils.