The erosion of soils due to water or wind can disrupt a network of creatures invisible to the naked eye. These organisms work together to compose a fertile and complete soil. When land is stripped of its natural vegetation, its protection against erosion results in soil losing its ability to hold water and nutrients.
As organic matter is lost, farmers or landowners may add fertilizers, pesticides, and herbicides frequently or aggressively in an attempt to bring back soil harmony. Communities of microbes are also disturbed in the process of tilling soil and during erosion events. As the soil loses its working populations of microbes, pH levels may rise or free fall. Pest infestation is much more likely and nutrient availability is heavily impacted.
Why Does Soil Matter?
The formation of soil first happens beneath the uppermost visual layer where plant growth takes place. The soil might contain several layers or horizons, each of which contributes to the structure of the uppermost layer; the topsoil. Beneath the topsoil is subsoil that can be negatively impacted by erosion, especially when pH balance reaches below the surface to make the proper balance of nutrients and gases that much harder to achieve.
The topsoil, or what geoscience refers to as the A horizon, contains a myriad of organic matter that contributes to overall soil health and productivity. Soil is composed of rock, clay, or sand as well as plant and animal tissue going through the process of decomposition. This breakdown of material contributes to a thriving microbial community working together to balance and regenerate the soil’s make-up.
What Happens in Soil Erosion?
Agricultural land can experience rates of erosion 10 times the normal rate of loss. Approximately 1,500 feet of soil loss per 1 million years can be attributed to agriculture. While that may not seem like much, consider that the normal rate from natural erosion events is 60 feet of soil loss per 1 million years. Also considering that it takes thousands of years for soil to form and populate, the loss of half the world’s topsoil is a devastating consequence and one from which nature may struggle to rebound.
What Are Soil Microbes?
Soil is a living, moving substance that is home to different types of bacteria that contribute to the soil’s composition, nutrient availability, and recycling processes. These microbes are vital to soil health and aid in the breakdown of organic material like decaying plants and animals.
Microbes help to complete biochemical processes such as transforming nitrogen to a form usable by plants. Microbes contribute to the recycling of nutrients, thereby rebuilding the soil’s structure over and over again.
Soil contains aggregates that help protect its rate of decomposition. The National Resource Conservation Society defines soil aggregates as: “Soil aggregates are groups of soil particles that bind to each other more strongly than to adjacent particles. The space between the aggregates provides pore space for retention and exchange of air and water.”
Tilling land breaks down soil aggregates to compromise soil stability. As aggregates are crushed under heavy machinery, carbon might be released and soil microbes may overfeed on a now abundant energy source. As microbes feast, their normal rate of decomposition and recycling is disrupted. Once the feeding frenzy is finished, nutrients are not replaced and microbes die out once the food supply is exhausted. The living soil then becomes vulnerable to pests, inciting producers to turn to pesticides and other chemicals to restore balance.
Are There Different Types of Soil Microbes?
Microbes are the working group that continuously renews soil’s breakdown-rebuild process. They can be divided into sub-categories:
- Micro-organism: Consists of soil bacteria, fungi, protozoa, and nematodes.
- Mesofauna: Includes mites, springtails, proturans, and pauropods.
- Macrofauna: These are in the form of earthworms and termites.
Soil microbes are generally comprised of these groups with most microbes taking on the role of decomposers. This group can consume simple carbon compounds while they break down pesticides and pollutants. Decomposers work to retain soil nutrients as well as prevent the loss of nutrients such as nitrogen. The rest might form partnerships with plants to exchange nutrients or contribute to the recycling of nitrogen and the degradation of pollutants.
As wind and water erosion strip away beneficial topsoil, biodiversity takes a hit and microbe populations suffer. Once these tiny organisms and beneficial bacteria are not in place to do their jobs, soil integrity is lost and will struggle to recover. Moreover, unhealthy soil can move and expand into other areas when it is left unprotected.
Steps to Aid Soil Recovery
Water and wind erosion can have serious effects on soil’s microbial health. As conditions for recovery continue to be assessed and evaluated, steps can be taken now to help minimize the effects of erosion on the soil’s hard-working microbial colony.
Over-tilling soil and stripping the land of its protections put soil at risk. Replacing the vegetation that aids in feeding the soil’s microbes helps to counterbalance the loss of those tiny creatures. Bare land sets the stage for wind or water erosion and altering planting techniques (strip-farming, terracing, no-till) can lessen the disturbance of the soil. Using coir geotextiles can assist soil by holding it in place, keep it from drying out, or balance soil’s pH for a thriving microbe community.
Soil health is dependent on several factors and when one or more are imbalanced there is cause for concern. When microbe activity is disrupted or if its natural decomposition cycles are altered, soil quality suffers. Resulting issues of erosion, pH imbalance, and loss of soil fertility all adversely affect the soil’s ability to continue to produce.
Once the protection of soil is as big a priority as its use to grow and produce is, human activity can turn the man-made tide to encourage a thriving microbial community. Reducing damaging practices and adding natural textiles and plants can help curb erosion and hold soil in place. Earth’s upper layer is where we build and live. Protecting that layer encourages the soil to continues to produce and recover with the help of its microbial village. Time and space are critical components for these little guys to help soils convert food to energy, aid decomposition, and regenerate earth itself.