4
RUDN University Soil scientist found out the difference between the contribution of bacteria and fungi in the carbon cycle in the soil

RUDN University Soil scientist found out the difference between the contribution of bacteria and fungi in the carbon cycle in the soil

The soil scientist RUDN studied how the soil microbiome affects the release of carbon dioxide. It turned out that bacteria prefer readily available hydrophilic compounds, while fungi prefer stronger hydrophobic ones. The results will help to better understand how to properly fertilize the soil and how soils can help in the fight against greenhouse gases.

Mineralization of soil organic matter is a necessary stage of the carbon cycle. Organic residues completely decompose to oxides and salts — that is, to a form available for plant nutrition. At the same time, carbon dioxide is released into the atmosphere — the main greenhouse gas that leads to global warming. The intensity of mineralization is affected by the proportion of so-called dissolved organic carbon - water-soluble organic compounds that enter the soil, for example, from plant roots. These substances are divided into hydrophilic (sugars, amino acids, carboxylic acids, etc.) and hydrophobic (lignin and lipids). It is assumed that hydrophilic compounds accelerate the mineralization of soil organic matter to a greater extent — they are more accessible to microorganisms that decompose it. However, experimental evidence for this has not yet existed.

"We sought to quantify the differences in the mineralization of hydrophilic and hydrophobic fractions of the soil, as well as to clarify the underlying mechanisms controlled by bacteria and fungi," said Doctor of Biological Sciences Yakov Kuzyakov, Head of the Center for Mathematical Modeling and Design of Sustainable Ecosystems, RUDN University.

It is possible to find out how hydrophilic and hydrophobic substances affect the rate of decomposition of soil organic matter by the volume of carbon dioxide released by the soil. Soil samples for the experiment were taken at two points in the Chinese province of Hunan - moist soil of a rice field and dry soil from a hill. The points were chosen in such a way that the microbial composition differed in them — this will allow us to find out the contribution of individual groups of microorganisms. Soil scientists added hydrophilic and hydrophobic organic residues to the samples, after marking them with a rare isotope of carbon —13C. For 40 days, the samples were stored in a dark container at a temperature of 25℃, carbon dioxide emissions were measured every few days.

On the first day, mineralization was 3.6-70 times faster for the hydrophilic fraction. Moreover, the "embedding" of the hydrophilic fraction in bacteria was 11.4-16.4 times greater than in fungi. For the hydrophobic fraction, the ratio is the opposite — their embedding in fungi is 1.5 times greater than in bacteria. This indicates that fast-growing bacteria have a greater influence on the assimilation of the hydrophilic fraction, and slow—growing fungi - hydrophobic. Decomposition of both hydrophobic and hydrophilic compounds took place faster in dry soil from high ground — there was released about 90 mg/kg-1 more carbon dioxide than from moist rice soil (49.4-54.5 mg/kg-1).

"Understanding the dependence of the carbon cycle in the soil on its composition will help in the future to develop methods for maintaining soil fertility based on biotechnology and regulation of the soil microbiome," said Doctor of Biological Sciences Yakov Kuzyakov, Head of the Center for Mathematical Modeling and Design of Sustainable Ecosystems, RUDN University.

The results are published in the journal Biology and Fertility of Soils.

Visiting Professors View all
03 Nov 2017
Michele Pagano is a graduate of the University of Pisa, a leading scientist, the author of more than 200 publications in international journals, and a participant in many international research projects
1829
International Projects View all
Similar newsletter View all
31 Mar
RUDN University awards for specific areas of science and technology based on the results of 2021

Every year, RUDN University selects the best of the best in the field of science and innovation and encourages with a special reward. Since 2009, the Academic Council of the University has been awarding one reward in natural and technical sciences and the other one in social and humanitarian sciences. Both individual researchers and groups of authors can become laureates.

46
31 Mar
International Day of Women and Girls in Science: women scientists of the RUDN talk about their path to science

“Science is the basis of all progress that facilitates the life of mankind and reduces its suffering,” — Marie Sklodowska—Curie. A symbol of a woman’s success in science. The first scientist in the world — twice winner of the Nobel Prize.

290
31 Mar
RUDN University Mathematicians Create a Model for Queue Organizing with Self-Sustained Servers

RUDN University mathematicians proposed a model for optimizing the operation of queuing systems (from computer networks to stores). Unlike analogues, the servers in it are self-sustained. They can determine when to start and stop working themselves. Such a model can be useful, for example, for online taxi services and other systems where workers choose their own operating hours.

57
Similar newsletter View all