From a critical new study Cornell UniversityScientists have discovered that microscopic organisms known as microbes significantly influence the amount of carbon stored in soil, a finding that has profound implications for mitigating climate change and improving the health of agricultural soils.
Microorganisms are important actors in the soil carbon cycle. The study authors determined that microbial processes are four times more critical to carbon storage than any other process, including biomatter decomposition. This finding is particularly critical because our planet’s soil contains three times more carbon than the atmosphere, acting as a crucial carbon sink in our fight against climate change.
Published in the journal Nature, the research presents an innovative technique to delve into the complexities of soil carbon dynamics. The method marries a microbial computer model with data assimilation and machine learning to closely analyze large data linked to the carbon cycle.
How was the study conducted?
At the heart of the investigation is a measure known as microbial carbon utilization. This metric reveals the amount of carbon used by microorganisms for growth and the amount used for metabolism. The carbon microbes use for growth is sequestered within their cells and ultimately in the soil.
On the other hand, the carbon used for metabolism is released as a by-product in the form of carbon dioxide, which contributes to the greenhouse effect. The team concluded that microbial growth plays a more critical role than metabolism in determining soil carbon storage.
Professor Yiqi Luo, senior author of the study, emphasized the importance of these findings: “This work reveals that microbial carbon utilization is more important than any other factor in determining soil carbon storage.”
These new insights lead agronomists to explore agricultural management practices that influence microbial carbon use efficiency, thereby increasing soil health and food security.
Future studies may aim to increase soil carbon sequestration by microbes and explore how different types of microbes and substrates (such as sugar-rich ones) affect soil carbon storage.
A new method used to evaluate soil dynamics
Although research has focused on soil carbon dynamics for two centuries, previous studies have mainly focused on the amount of carbon entering the soil through foliage and roots, and the amount lost as CO2 to the air during decomposition of organic matter. “But we are the first group to be able to assess the relative importance of microbial processes to other processes,” Luo said.
In a groundbreaking move that shows the power of digital agriculture, Luo and his team devised a new method to assimilate big data into an Earth system computer model using data assimilation and machine learning. The model revealed that carbon use efficiency of microbial colonies significantly outperformed other factors assessed, such as decomposition and carbon inputs.
An innovative process-based model and machine learning approach provides a new way to analyze other types of large data sets.
This study was funded by several institutions, including the National Science Foundation, the National Key Research and Development Program of China, and the National Natural Science Foundation of China.
More on the importance of soil
Soil is not a simple mixture of minerals and dead plant material. It is a vibrant, living ecosystem filled with life forms ranging from the visible like insects and worms to the invisible like bacteria and fungi. Among invisible organisms, microbes play a particularly crucial role.
Microorganisms are microorganisms that include bacteria, archaea, fungi, algae, viruses, and protozoa. Soil is one of the most diverse ecosystems on Earth, with microbial diversity estimated to reach one trillion species.
Microbes are an important part of the soil food web, a complex network of organisms that transfer energy and nutrients through the soil. They are involved in a wide range of processes vital to soil health and the wider ecosystem.
One of these processes is decomposition. Microbes break down dead plants and animals, turning organic matter into simpler compounds. This process recycles nutrients back into the soil, making them available for plant uptake.
An important role of microorganisms is their contribution to the carbon cycle. By decomposing organic matter, microbes convert the carbon it contains into a form that plants can use. They also help sequester carbon in the soil. When microbes consume organic matter, some of the carbon is stored in their cells. When they die, this carbon becomes part of the soil organic matter and is effectively stored in the soil.
Nitrogen fixation is another important process performed by certain soil microorganisms. Certain bacteria, especially those that live in symbiosis with leguminous plants, can take nitrogen from the air and convert it into a form that plants can use. This process is a critical part of the nitrogen cycle and helps maintain soil fertility.
Also, soil microorganisms play an important role in soil structure. Through their actions, they help create soil aggregates—small clusters of soil particles. These aggregates improve the soil’s ability to hold water and air, supporting plant growth.
However, soil microbial communities can be sensitive to changes in their environment, including changes in temperature, moisture, pH, and the introduction of chemicals or pollutants. Agricultural practices such as excessive use of chemical fertilizers or pesticides, or practices that lead to soil compaction or erosion, can harm these communities and disrupt important processes they carry out.
In summary, soil microbes are critical to soil health, plant growth, and the global carbon and nitrogen cycles. Understanding and protecting these tiny soil inhabitants is critical to sustainable agriculture and a healthy planet.
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