The foundation of a healthy garden starts with healthy soil. An important but often overlooked attribute of healthy soil is the existence of a diverse underground food web.
According to a study published in the Journal of Applied Ecology, “Potential roles of soil fauna in improving the efficiency of rain gardens used as natural stormwater treatment systems” by Andrew S. Mehring and Lisa A. Levin: “Soil fauna commonly found within soils of rain gardens have the potential to substantially alter plant growth, water infiltration rates, and the retention and removal of pathogens, nutrients, heavy metals and other contaminants.” Invite soil fauna into your garden by ensuring the proper environment.
So, the question becomes, how do we invite soil fauna into our garden? The answer: by creating the proper underground environment. By volume, soil is 25% air, 25% water, 45% minerals and 5% organic matter. The composition may vary slightly depending on the soil type and location. Organic matter, although least in overall percentage, is necessary to support an abundance of life in the soil. It provides food, shelter, air and water for soil organisms. In addition, organic matter creates pore space, which improves water-holding capacity. It improves soil structure, thereby increasing water filtration. Send a soil sample to Rutgers Soil Testing Lab for an exact determination of the composition of your soil. If necessary, enhance your soil by adding organic matter in the form of compost, leaves, shredded mulch, or a mixture of each.
Healthy soil is a living ecosystem, teeming with life. Bacteria, fungi, protozoa, nematodes, arthropods and earthworms dominate the soil ecosystem. Each plays a vital role in maintaining soil health.
Bacteria are single-celled pioneers. Before plants can become established on a mineral substrate, the bacterial community must establish themselves first. They are both predator and prey within the soil ecosystem, controlling populations of disease-causing organisms and providing food for protozoa and nematodes. Bacteria enhance soil structure and degrade pollutants.
You’re likely to see fruiting bodies of fungi in the form of mushrooms on fallen trees and rotting logs, or colonizing thick layers of mulch. Fungi are able to decompose complex carbon compounds found in wood. Fungi grow as long strands called hyphae, which push their way through the soil, reaching several meters or more. Masses of fungal hyphae grow into mycelium which form relationships with plant roots, creating a pipeline for nutrients that are too far away plant roots to reach on their own. By adorning your garden with logs, or by adding mulch, you will be supporting fungi, as well as myriad decomposing soil organisms.
When microscopic protozoa eat bacteria, the nitrogen contained within is released into the soil, providing food for plants. Protozoa also provide a food source for nematodes, which are small, unsegmented round worms that live in small pockets of water found within the pore spaces of organic-rich soil. Nematodes are often blamed for feeding on plant roots, however, as with every ecosystem, a balance of predators and prey keep the system in check. Most nematodes are beneficial, and assist with the important job of decomposing organic matter, which adds nutrients to the soil and increases water absorption and infiltration.
You’re probably familiar with arthropods living in your garden soil and can possibly identify a few: spiders, mites, sow bugs. Their continuous movement through the soil creates soil structure and pore spaces which helps prevent compaction. Their fecal pellets contribute nutrients, which are deposited in the soil through castings. Worm burrows create tunnels for air and water; and space for plant roots to grow deeper. Water is channeled and absorbed more quickly into the soil.
Biodiversity within the underground soil ecosystem keeps your garden functioning at optimum health and able to manage stormwater more efficiently and effectively. Rototilling, chemical fertilizers and pesticides are detrimental to the organisms that create the soil food web. When planning your rain garden, bioswale or simple flower patch, remember that a foundation of healthy soil is the key to a successful project. Dig deep and renew your appreciation and understanding of your soil!
Go Green Galloway is a volunteer organization dedicated to reducing the carbon footprint of Galloway through the promotion of energy efficiency and conservation, environmental education and the implementation of sustainable practices. We always welcome new volunteer members. Contact us at firstname.lastname@example.org or call Mary at 609-742-7076. Also be sure to like our Facebook page.