Growing Green: Soil, Our Lives Depend On It

The cover crop is mowed, well, mostly. When the 1949 well-loved, but very temperamental tractor decides it’s in the mood to turn over, the last patch will be finished. Recently, a neighbor took a look at the growing cover crop, and offered to mow the “weeds” for me. Granted, there are plenty of weeds thriving among the cover crop, but most of what’s growing (or was growing), was planted there intentionally. We chose a mix of vetch, rye grass and bell beans as our winter cover crop. Mowing the cover crop has me thinking about soil, but really all aspects of growing food relate back to the health of the soil.

The word dirt creates an image of an undesirable substance that was accidentally tracked through the house, or simply a medium used to anchor the roots of vegetables and flowers in the garden. Soil on the other hand, speaks to an incredibly complex living and breathing ecosystem, chock full of organisms, minerals and nutrients. Soil is the living skin that covers the earth. I recently saw a children’s lesson on the importance of soil. A teacher explains to the students that the earth is covered in topsoil that contains all the living and nonliving things plants need to grow. Once this topsoil is scraped off or depleted of life, it will no longer be able to grow food. She uses an apple as a visual, explaining that topsoil is like the skin of the apple, and proportionately as thick. I thought this was a great lesson to help young students begin to develop a respect for soil. This apple skin that covers our earth and allows us to survive, is only a foot or so deep. It would take more than five generations for one inch of topsoil to form. If you haven’t seen “Dirt! The Movie,” it’s definitely worth watching. Narrated by Jaime Lee Curtis, the film explores all aspects of soil, and the world within and around it.

One would think that as producers and consumers, we would do everything in our power to preserve this precious apple skin. Unfortunately, the increasing industrialization of our food system, with practices including intensively working the soil with heavy equipment, growing just one or very limited crops without rotating the crops to help restore the soil health, over irrigation, application of inorganic fertilizer, chemical pest control and genetic manipulation of crop plants (also know as GMOs), have led to the destruction of this precious topsoil.

In short, we are peeling away our apple skin, that which cannot be regenerated for over 500 years, at rocket speed. Simply driving down my street after a recent rainstorm and gazing up at strawberry fields on a sloping hillside provided a snapshot of deep crevices between the rows in which the topsoil had been washed away down the hillside. This is likely the product of a degraded soil, which as a result of intensive pesticide application, lacks the organic matter—and therefore structure—to prevent it from being washed away. As early as 1990, the World Resources Institute reported poor agricultural practices contributing to the degradation of 38 percent of the cropland worldwide, with more recent reports of as much as 75 percent in some areas.    

One widely recognized practice that helps to protect the soil rather than destroy it, is the practice of planting a cover crop. Cover crop (also referred to as green manure), is any crop that is grown for the purpose of feeding soil organisms (thereby increasing your soil fertility), rather then being harvested to sell or feed to livestock. Often cover crops are grown between seasons, for example planted in November and then mowed before seeds are dropped in the spring. I enjoy driving around Watsonville in the winter, and looking at the variety of different cover crops being grown. By growing cover crops, and then turning them into the soil, we are stimulating microbial activity, capturing, releasing and recycling nutrients, naturally suppressing weed growth and helping to prevent erosion. As we are harvesting food, and taking away nutrients from the soil, cover crops are one way of returning some of what we take away.

Now that the cover crop is about to drop thousands of seeds, (which we hope to avoid), and it’s time to get the summer crops planted, the tricky piece is timing with the weather. We want to mow the cover crop down and disc the soil to prepare for the mouth-watering summer planting of a wide range of veggies and fruits. However, driving a tractor (or even walking) on wet soil will collapse the airspaces, causing compaction, and ultimately harming the soil. So, we are currently waiting for that critical window, where the soil is dry enough to work so we can turn in the dried down bell beans, vetch and oats, feeding the hardworking critters, and strengthening the structure of the soil. Fingers crossed the tractor starts when that window arrives...