The holy grail of organic gardeners and farmers is how to build topsoil replete with organic matter, high levels of sequestered carbon and an alphabet soup of microbes and fungi. Fall is the best time to prepare for next year’s planting. While soil fertility is an ongoing topic for gardeners and farmers, there are many methods and practices that increase soil fertility. One of the main indicators of soil heath is the amount of organic matter found in soil. The ideal soil makeup is one third clay, one third sand and one third organic matter.
“By growing trees, shrubs and other perennial plants among crops in the field, African farmers can revitalize some badly depleted soils while raising food yields.”
Scientific America-May 2016
Nitrogen fixing plants and their roots create soil structure which helps create the microbiome. The microbiome is the ecological system that creates soil. Billions of bacteria, mycorizzial fungi, nematodes and other soil organisms interact to form soil particles that glue the soil together and make a home for the roots of plants in a chorus of symbiotic relationships
This is self-explanatory and consists of gardening or farming without using tillage. The seeds are simply planted directly into the residue of the last crop.
Adding biochar to soil helps lock up more carbon. New research from Cornell University suggests biochar may be a way to scrub carbon from the atmosphere.
According to Biochar-International.org, “Carbonization is the process of converting a feedstock into biochar through reductive thermal processing. The process involves a combination of time, heat and pressure exposure factors that can vary between processors, equipment, and feedstocks.”
“There are two main processes: pyrolysis or gasification. Energy products in the form of gas or oil are produced along with the biochar. These energy products may be recoverable for another use, or may simply be burned and released as heat.”
“In addition, biochar can be made from a wide variety of biomass feedstocks. As a result, different biochar systems emerge on different scales. These systems may use production technologies that do or do not produce recoverable energy as well as biochar, and range from small household units to large bioenergy power plants”
Prairie roots create deep soil layers that are as effective as trees in sequestering carbon. These gardens and natural areas can, over time, create inches of topsoil with the perfect community of microorganisms in a stable matrix of strong roots where erosion just doesn’t happen.
A completely sheet-mulched garden is a permaculture method that creates conditions to build up soil health and volume. Sheet mulching, also known as lasagna gardening adds layers of cardboard, newspaper, compost, leaves and woodchips. This suppresses weeds, composts on site and adds organic matter.
This is another permaculture method and it is amazing. It is simply digging down into a garden site, then laying in a dense woodpile and covering it over with the soil removed from the hole. Cover the area with a straw mulch then plant or seed in vegetables. The logs slowly break down and retain moisture. A Hugelkultur bed looks like a raised bed garden and require low or no watering.
These 5 methods help attract, build and feed organisms in the soil that sequester carbon and nitrogen and create conditions that allow the recharging and restructuring of soil.
Caron Wenzel is an Environmental Educator, writer, and owner of Blazing Star Inc. a 26-year-old native plant seed nursery, soil amendment and environmental consulting business. You can visit her website at Blazing-Star.com.