The Dirt On Soil

What is soil microbiology?

Soil microbiology is the study of the microbes in soil, their functions, and the ways they affect soil properties. It is believed that the first ancient bacteria and microbes appeared in Earth's oceans two to four billion years ago. These bacteria can fix nitrogen and multiply over time, thereby releasing oxygen into the atmosphere. This has led to the emergence of more advanced microbes, which are important because they affect soil structure and fertility. Soil microorganisms can be divided into bacteria, actinomycetes, fungi, algae and protozoa. Each group has characteristics that define them and their function in soil.

Soil scientists, environmental scientists, and others, including soil health and conservation experts, will find this material invaluable for understanding the surprisingly diverse world of soil microbiology, managing agricultural and environmental systems, and developing environmental policy.

Importance of soil microbiology.

Soils with high microbial abundance and diversity can support pathogen suppression, increase nutrient availability for crops, and enhance nutrient cycling, but may also hinder plants from finding high-quality partners for special symbiotic relationships.

Because soil microbes are concentrated around plants, including agricultural crops, the activities of soil microbes can have significant effects on soil and crop health. Some microbes are free-living and influence plants through their activities in soil and rhizosphere environments, while other microbes go one step further and form intimate symbiotic associations with plant roots. In some cases, these symbiotic partners reside inside plant tissues themselves. Below, we discuss some of the important ways that both free-living and symbiotic microorganisms influence agricultural systems.

Fertile soils require a mix of beneficial microbes and an absence or low presence of harmful microbes. A lack of enough beneficial microbes in the soil results in a chain of disruption that affects all the plants or crops growing within it. Some of these negative impacts of a soil microbiome in disrepair include:[5].

Applications of soil microbiology in agriculture and environmental management.

Microbial soil amendments can support the microbiome and increase soil microbial activity. By studying diverse agroecosystems, targeted microbial soil amendments have been developed as a tool for farmers to add into their management practices not unlike the use of fertilizer and some tillage practices.

Farming can destroy soil's Rhizobium (microbial ecosystem) by using soil amendments such as fertilizer and pesticides without compensating for their effects. By contrast, healthy soil can increase fertility in multiple ways, including supplying nutrients such as nitrogen and protecting against pests and disease, while reducing the need for water and other inputs. Some approaches may even allow agriculture in soils that were never considered viable.