Vital Signs/Carl Bucholt
By a happy coincidence, two of my passions – vegetable
gardening and climate activism – seem to have converged. It turns out that regenerative agriculture helps improve soil health and productivity, while at the same time improving the climate by sequestering carbon in the soil. Let me explain: I’ve been growing my own vegetables for over 40 years. Every spring, I would rototill the garden, make my rows and plant. After harvest, I tilled the garden again, leaving a blank slate over the winter to be tilled and planted the next spring. We often spoke about planting a winter cover crop but never got around to it; we thought, “If it ain’t broke, don’t fix it.” Imagine my surprise when I recently learned that something was broken – the carbon content of our soil. We humans are carbon-based life forms, and so is everything else that grows on this planet, including the plants we eat. Soil needs plenty of carbon to supply all the nutrients vegetables need – but tilling depletes the carbon and adds carbon dioxide to the atmosphere. How? Tilling introduces large amounts of oxygen to the soil, increasing the decomposition of organic matter; any carbon in the soil combines with this newly introduced oxygen to create carbon dioxide. If soil is not disturbed, the carbon stays in the ground.
Keeping carbon in the soil through regenerative agriculture is one of the most effective strategies for reversing global warming. It’s estimated that 50 percent of the carbon in the earth’s soil has been released into the atmosphere in the last few centuries, approximately 80 billion tons. Turning over topsoil also destroys beneficial bacteria and microbes in the soil. Plants take carbon dioxide from the air and through photosynthesis put oxygen back into the soil to create carbon – the food that the microbial network needs to make them bio-available to plants. Healthy plants release sugars through their root systems that feed and stimulate the microbes to release trace minerals, which are transferred to the plants, thereby increasing the nutrition of our food. (In healthy soil, there are more microbes in a teaspoon of soil than there are people on the planet.)
Regenerative farmers employ cover crops (sometimes several varieties together) to add nutrients to the soil, which supports the growht of their cash crops. It’s also an herbicide-free method of suppressing weeds and minimizes or eliminates soil run-off and erosion after heavy rains. Many farmers purposely plant crops or flowers or create hedgerows to attract beneficial insects which help with pollination and keep harmful insects under control, thereby eliminating the need for pesticides. Larger farms often use managed grazing to complete the natural cycle of fertilizing the earth and stimulating plant growth. (Plants get stressed after being eaten, so they initiate a positive feedback loop with the fungi and microbes in the soil to speed re-growth.) Regenerative agriculture practices hold hope for a better environment by sequestering carbon in the soil, thereby actually reducing global warming and improving the health of our soil, thereby improving the nutrition of our food and improving human health.