Underground Jungle
When you visit the farm, you see the vegetables
and forage crops growing above ground, and it's easy to forget there's a whole
world below the earth's surface that makes these plants what they are. Plant
roots are the unsung heroes of organic farming systems. Their structures are
just as diverse as the aerial plant parts we see and have come to appreciate.
The intricacies of roots' interactions with the soil and the soil food web are
the driving force of the food we eat. Let’s take a peek at what is going on
down there.
A seed is said to germinate when the initial
root—called a radicle—breaks through the protective coating of that seed. This
baby root is feeding off the energy stored in the seed as it naturally turns
downward in search of moisture and nutrients to feed the leaves that are soon
to develop. As the spike-like root spears deeper into the ground, small root
branches begin to spread laterally to begin anchoring the plant in preparation
for the taller, leafy growth that will be exposed to the elements above the
soil. As the plant matures, the root structure develops in a pattern unique to
its genetic code.
Generally speaking, there are two basic types
of root systems: tap and fibrous. Tap roots have a dominant shaft that dives
deep into the soil, while fibrous root systems are a series of uniformly sized
structures that fan out into the soil. Tap roots not only physically penetrate
through denser sub-surface soils—even the tighter, clay soil profiles—but they
are able to bring nutrients up to the surface that otherwise would not be
available to the plant. Fibrous-type structures send their tentacles in all
directions in search of nutrients and moisture. We use these differences to our
advantage when planting cover crops and designing crop rotations. Water goes
into the roots and out the leaves, called transpiration, which is akin to the
chimney effect. The leaves then send down the nutrients they've accumulated
through photosynthesis to feed the roots.
Building the Soil Food Web
Here is where plant roots get interesting. Whenever
top growth of a plant is removed, such as when you cut the grass or when we
harvest the outer leaves of kale from a plant, an equivalent amount of root
growth dies, because there is not enough food available for all of them. When
these roots decay, they provide nutrition to the soil microbes—bacteria and
fungi—that feed on such plant material. The space where the now-dead root was
also leaves a small void in the soil for air to move deeper into the ground,
oxygenating those same microbes. There are tens of thousands of species of
bacteria and fungi, each with unique growth and feeding requirements. Some like
it hot, others cold, some wet, others dry, some high pH, others low. This cycle
of new root growth and subsequent decay is how we build soil.
The interface between roots and the soil they
live in is wildly intricate. The roots are not selfish with the nutrients they
get from up top. They exude a nutrient-dense solution back into the soil, which
further energizes the microbial flora and fauna around them. This symbiotic
relationship is best seen with a class of fungi known as mycorrhizae. These
filamentous-like fungi attach themselves to the roots, then form microscopic
threads all through the soil profile, extracting specific nutrients, like
calcium, phosphorus and magnesium. They then transfer the nutrients to the
root, which sends them to the leaves or the fruits we eat. The roots cannot do
this work on their own. Healthy soils are said to contain 20 miles of mycorrhizae
fungi in a single teaspoon. When a plant has the balance of nutrients that
match its genetic code, it can fend off disease and pestilence. This is the
genesis of organic principles.
Within
this complex, synergistic, nutrient sharing is a communication feedback loop
that is a bit counterintuitive. For example, weeds that have a relatively
higher concentration of zinc will grow in an area low in zinc. By doing so, the
mycorrhizae and root systems mine the soil for zinc and send it to
the top of the plant to be deposited on the surface of the soil at some point,
therefore correcting the zinc deficiency in the soil. We manage the types of
plants we grow to cycle those nutrients back into the working surface of the
soil.
So, you see, the roots are much more than
structural necessities. The wildly diverse and symbiotic jungle of plant
tissue, microbes and insects cohabitate to create healthy plants. Please take a
moment to consider that the produce you receive each week is just as nature
intended. With a little help from us. —Mac Stone
In Your Share:
Asparagus
Fresh Herb: Oregano
Lettuce
Spinach
Strawberries
Sugar Snap Peas
Red Russian Kale
Recipes
Lettuce Soup, from Epicurious
1 c. chopped onions,
scallions or shallots
1 garlic clove, chopped
3 T. unsalted butter
3/4 tsp. ground coriander
3/4 tsp. salt
1/4 tsp. black pepper
3/4 c. diced (1/3 in.),
peeled potato
8 c. coarsely chopped lettuce
leaves, including ribs
3 cups water or vegetable or
chicken broth
Cook onion mixture and
garlic in 2 tablespoons butter in a 4- to 5-quart heavy pot over moderately low
heat, stirring, until softened, 3 to 5 minutes. Add coriander, salt and pepper
and cook, stirring, 1 minute. Stir in potato, lettuce and water and bring to a
boil, then reduce heat and simmer, covered, until potato is very tender, about
10 minutes.
Purée soup in batches in a
blender (use caution when blending hot liquids) and transfer to a 2- to 3-quart
saucepan. Bring soup to a simmer, then whisk in remaining tablespoon butter and
salt and pepper to taste. Serves 4.
Strawberry-Avocado Salsa, adapted from Cooking Light
1 1/2 c. chopped
strawberries
1/2 c. diced, peeled, ripe
avocado
2 T. minced, seeded jalapeño
pepper
2 T. chopped fresh cilantro
2 tsp. fresh lime juice
1/4 tsp. kosher salt
Combine all in a bowl. Serve
over grilled chicken, alongside a Mexican-inspired meal or with vegetable chips
as a snack.
Sugar Snap Peas with Onions and Bacon, adapted from FoodNetwork.com
3 slices bacon, cut into
1/2-inch pieces
1 small, yellow onion,
peeled and chopped
1 lb. sugar snap peas
1/2 c. water
salt & pepper
In a medium skillet over
medium-high heat, brown chopped bacon. Using a slotted spoon, remove bacon to a
paper towel-lined plate. Add onion to the pan. Sauté onions 3 minutes or so,
until they are just tender. Add peas and water to the pan. Cover and cook 5
minutes. Uncover and allow the liquid to cook almost out of the pan. Add bacon
back to the skillet and remove pan from heat. Serves 4 as a side.
Raw
Asparagus Caesar Salad,
adapted from Serious Eats
You
can also make this recipe with the sugar snap peas in place of or in addition
to the asparagus called for here.
1 bunch asparagus, ends
trimmed and chopped into 1/2-inch pieces
1 T. mayonnaise
1 1/2 T. red wine vinegar
2 T. freshly squeezed lemon
juice, from 1 lemon
2 garlic cloves, roughly
chopped
1 tsp. Dijon mustard
1 tsp. Worcestershire sauce
1 tsp. anchovy paste (or 1
anchovy filet)
6 T. extra virgin olive oil
salt & pepper
1/2 c. shaved
Parmigiano-Reggiano
Combine mayonnaise, red wine
vinegar, lemon juice, garlic, Dijon mustard, Worcestershire sauce and anchovy
paste in a blender. Blend until smooth. Transfer to a medium bowl. Whisking
constantly, add the olive oil in a thin, steady stream until incorporated.
Season to taste with salt and pepper. In a medium bowl, toss the asparagus with
the dressing. Transfer to a serving platter and top with the
Parmigiano-Reggiano. Serves 4 as a side.
