Artificial humic substances improve microbial activity for binding CO2

Chunyu Tang,Yuelei Li,Jingpeng Song,Markus Antonietti,Fan Yang

doi:10.1016/j.isci.2021.102647

Chunyu Tang, Yuelei Li + Show 3 more

Open Access

https://doi.org/10.1016/j.isci.2021.102647

Copy DOI

Abstract

SummaryHumic 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.

Highlights

Humic substance (HS) is the product of humification, the second largest process after photosynthesis in the aspect of terrestrial carbon cycle (Hedges and Oades, 1997), and is considered by most to be a resistant substance, which is converted from living organic matter by chemical-microbiological functions (Lehmann and Kleber, 2015)
Originally, we specially compared the results through principal-component analysis (PCA) to intuitively understand the effects of different HA and FA contents on soil carbon sequestration and nutrient availability (Figure S1)
PCA results visually revealed which index of soil property changes and allowed visualizing the relationship between the increase of total organic carbon (TOC) and dissolved organic carbon (DOC) and agriculture effect, total exchangeable base (TEB), and microbial effect in different treatments and cultivation period

Summary

Introduction

Humic substance (HS) is the product of humification, the second largest process after photosynthesis in the aspect of terrestrial carbon cycle (Hedges and Oades, 1997), and is considered by most to be a resistant substance, which is converted from living organic matter by chemical-microbiological functions (Lehmann and Kleber, 2015). Important for the present discussion, HS is the most promising carbon sink to mitigate atmospheric CO2. HS, as a vital component of soil organic matter, is one of the most important players in the global carbon cycle (Shan et al, 2010), and a change of its content on global farming areas has the potential to cure the climate crisis completely. Few studies have looked at the variation of bacterial communities involved in fixing CO2 under the condition of HS, especially those involved in the Calvin cycle

Methods

Results

Conclusion