What is your gardening style?
The way we garden can determine whether we increase or decrease greenhouse gases such as carbon dioxide. Carbon has been on my mind lately after the release of the alarming 2021 report “Climate Change 2021, The Basis of Physical Science” by the United Nations Intergovernmental Panel on Climate Change.
Forests and grasslands, which existed before today’s extensive logging and development, constantly returned organic matter to the soil as they grew, reproduced, died and regenerated.
Our ancestors fertilized with litter straw and manure, but in most of today’s agriculture the soil is plowed and planted, with chemical fertilizers and pesticides added, but little organic matter is returned to the ground.
When organic matter in the soil, such as roots and leaves, dead insects, compost and mulch that we add are broken down by microorganisms, the remaining material becomes humus, which is, among other things, the base. carbon storage in the soil. Humus is black largely because of its carbon content. So you can get an idea of how much carbon is stored in your soil based on how dark it is.
Humus, which is stable and resistant to decomposition, contains around 60 percent carbon, which can remain intact in the soil for hundreds or even thousands of years, until it finally decomposes completely and returns carbon to the air. Deforestation and poor farming (and gardening) practices over the past century have depleted soil carbon in the earth by up to 50 percent.
Return of carbon to the soil
According to the IPCC report, carbon dioxide levels in the atmosphere are higher than they have been for hundreds of thousands, if not millions of years. Returning carbon to the soil is one of the remedies.
In a previous article, I have recommended home landscapes as a good place to sequester carbon, but what about home gardens? A vegetable garden is not a very stable environment. We constantly plow and dig, change crops, and pull up plants and weeds. It is a problem. When we disturb the soil, we release carbon that is stored there. When exposed to air, carbon combines with oxygen and becomes carbon dioxide.
We can help return some of the missing carbon to the soil for storage by adding organic matter to our gardens. Leaf and straw mulches, compost and cover crops replenish the organic matter needed to create humus, nourish plants and store carbon.
Another way to help reverse destructive carbon depletion is no-till gardening. You can start a no-till garden from scratch or switch from traditional gardening to no-till over several years.
The bed without digging can start with cardboard
Direct seeding, sometimes called no-dig, is an easy way to create a raised garden on sod or other permeable surface. It does not require any digging, leaving the carbon reserves intact.
Start by laying one or two layers of cardboard over the footprint of your raised bed, and several feet beyond if you want mulched walkways around the bed. If the soil is particularly compacted, it is advisable to loosen it using a pitchfork or a garden fork, or even a lawn aerator, before laying the cardboard.
An optional layer of compost on the surface under the cardboard will initiate the production of the necessary soil life. When the cardboard is lowered and the raised bed has been built or placed on top, drill holes in several places through the cardboard so that water does not pool to drown the roots once the soil in the garden. has been added. Wet the cardboard well.
If a raised bed is more than 8 inches deep, a good option is to add sticks, leaves, and other garden debris such as banana leaves and stems first. This provides immediate material for decomposition and reduces the cost of filling the bed.
Fill the top six to eight inches with your choice of compost and garden soil, add a little mulch to retain moisture and suppress weeds, then plant seeds and seedlings. Simply move the mulch to the side where you want to plant.
Cardboard kills weeds and grass
The cardboard will kill the weeds and grass underneath, adding them to the soil as organic matter. Over the next six months to a year, the cardboard (also organics) will also decompose, worms and microorganisms will soften the soil below, and you will soon have a deep and fertile garden soil on the way to becoming. humus.
At this point, it is a good idea to plant root vegetables such as carrots, beets, turnips and daikon radishes to loosen and further aerate the soil and allow the carbon stores to blend deeper into the soil. Earth.
Once your raised bed is established, you can garden the traditional way or continue with no-till methods to conserve carbon stores and continue to feed your plants with organic matter. In raised beds or gardening in native soil, direct seeding involves cutting your healthy vegetable and cover crops to the surface of the soil and dropping them in place to serve as mulch, and planting crops. cover or new vegetable crops among fallen and decaying plants.
Cover crops prevent bare soil
Microorganisms, including the vast networks of fungi necessary for plant survival, are not disturbed. No-till gardening creates a more stable garden environment, reduces the release of carbon, conserves moisture, discourages weeds, prevents erosion and leaching, and provides a constant supply of slow-release nutrients to crops during that mulched plants decompose.
It works best when cover crops are planted between vegetable growing seasons so the soil is never bare. Pioneer plants (weeds) will soon take root where the soil is bare.
The transition from traditional gardening to direct seeding requires a period of several seasons of weeding and management. But eventually, if the crops are rotated, the cover crops are thick enough and diverse enough, and new weeds are not allowed to sow, weeds, pests and diseases will be discouraged and less care will be required.
It’s a great way to garden. For more information on direct seeding and a similar process called leaf composting, see the page UF / IFAS No-Dig Garden Beds Website.
When you’re ready to take the next step, advocate for regenerative farming practices, which address the same issues nationally and globally. Southern Sustainable Agriculture Research and Education, which is a grants and outreach program of the United States Department of Agriculture’s National Institute of Food and Agriculture (NIFA), has more information on regenerative agriculture (https://southern.sare.org/).
For more information on climate change, see the United Nations IPCC report on un.org/en/climatechange/reports.
Janis Piotrowski is a Florida Master Naturalist, Certified Permaculture Designer, and volunteer Master Gardener with UF / IFAS Extension Leon County, an equal opportunity institution. She hosts a blog on gardening and sustainable living in North Florida at https://northfloridavegheadz.blogspot.com. For any gardening questions, email the extension office at [email protected]
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