Rhizodeposition

What is Rhizodeposition:

Rhizodeposition refers to the chemical process that happens in the rhizosphere, a small area of the soil that is directly changed by the release of plant root products and the microbiome. Rhizodeposition refers to the process that happens in small gaps within the soil that can contain many types of bacteria, fungi and nematodes (worm-like parasites) that can feed off the products released by the plant roots. Products released from the plant roots can be elements such as Nitrogen, Carbon, and other different proteins and sugars, these feed the plant root's microbiome. This is a form of symbiosis (mutualism) between the microorganisms and the plant that benefits from products produced by the microbes in the soil. An example of this is antibiotics that will kill harmful bacteria in the plant. The microorganisms will also provide the plant with enzymes, plant hormones and phosphates as well.

Why is Rhizodeposition important:

Rhizodeposition plays a very important role in connection with the carbon cycle. Out of all the carbon that the plant absorbs through photosynthesis around 25% of the carbon will be released through the roots of the soil, this carbon is what many of the microorganisms feed on in regards to rhizodeposition. Without this exchange of carbon, the microorganisms would not have one of the most important building blocks to life and would likely die. Similarly, the plants would significantly lack the antibiotics, hormones, enzymes and phosphates required to survive and would either die or be very weak.

Examples of Rhizodeposition:

In a study conducted on Triticum Sp. (Spelt Wheat) it was found that the Spelt Wheat was more productive in the presence of microorganisms that make up the rhizosphere than the Spelt Wheat that contained minimal microorganisms (the study notes that it is hard to maintain sterile soil). Specifically, wheat benefiting from rhizodeposition was able to grow higher faster and develop a root system that went wider and deeper. Harvest size from wheat with microorganisms was also much larger compared to wheat without/lacking microorganisms.

Bicharanloo, B., Bagheri Shirvan, M., Keitel, C., & Dijkstra, F. A. (2020). Rhizodeposition mediates the effect of nitrogen and phosphorous availability on microbial carbon use efficiency and turnover rate. Soil Biology and Biochemistry, 142, 107705. https://doi.org/10.1016/j.soilbio.2020.107705

Villarino, S. H., Pinto, P., Jackson, R. B., & Piñeiro, G. (2021). Plant rhizodeposition: A key factor for soil organic matter formation in stable fractions. Science Advances. https://doi.org/abd3176