Throughout my thesis research, I have been reading multiple papers by Dr. Rattan Lal, a soil scientist at Ohio State University. Dr. Lal has also been featured on the Regenerative Agriculture Podcast where he gives an interview that offers background information on the importance of soil carbon, the mechanisms by which it can be lost and gained, and how it affects the soil.
The episode acts as a guidebook for the major processes that cause soil to gain or lose carbon. Carbon can be lost through erosion, decomposition, leaching, and volatilization. It can be gained when microbes turn residues into humus. Most of my research on carbon sequestration has been on different mechanisms that prevent carbon loss from the soil–like reducing till and maintaining cover crops to reduce soil disturbance and erosion. Other regenerative practices help to accumulate carbon in soils–like the addition of compost or manure, or more extensive use of perennials that have deep roots for deposition and leave behind beneficial plant residues. Much of this information focuses on just the soil and plants but doesn’t go into detailed discussion about the important role played by soil microbes. Dr. Lal’s description of the role of microbes in humification, and the harm that can be caused by extensive pesticide use that disrupts microbial communities offers another insight into the processes that must be protected to build soil carbon and the importance of reducing pesticide use.
Dr. Lal also discussed the role that policy could play in protecting soils, while we have a Clean Air Act and a Clean Water Act in the U.S., no such policy exists for soils. Given the size of the carbon pool that soils represent and their importance in ecosystem health and supporting life across all trophic levels, it would seem intuitive to write policy aimed at their preservation and create incentives for farmers and ranchers to take up practices that build soil carbon and enhance soil health.
This podcast was a great review of some of the same soil processes I am reading and writing about in my own research, and it provided me with new ideas on the importance of soil microbes and soil policy–take a listen below!