- daffodils, courtesy of Scott Liddel.
- fossil, courtesy of Karolina Przybysz.
A host of golden daffodils. The purple phlox blooming.
This winter was long and hard, but the weather has finally warmed enough. Ive been out in my pasture, sawing up dead tree limbs that crashed to the ground during a severe February ice storm. Ive stacked the logs in my woodpile, preparing for the next cycle of nature. Ive sharpened the blades of my gartenblechle, or plow/cultivator, and Im pushing it back and forth across the soil of my vegetable plot. I turn under the dried manure and compost that I had spread on the ground last fall. The dark, rich soil is moist and crumbly, its odor filling my nostrils. The tines of the plow dig deeper into the soil, turning up shiny earthworms. Once my ground is finely tilled, I mark the rows with another important garden tool a piece of string. Each end anchored to a stake, the string unwinds in my hands. I push one stake into the ground, then pace out the distance of a row. I push the other stake into the ground and tap it in place with a rubber hammer.
A perfectly straight row is now ready for my third most important garden tool the bulb planter. I sink the planter into the garden soil to create holes for my transplants. Tightly gripping the handle, I lean my weight into the tool and understand what a paradox it is to work the ground. In prehistoric times, the cultivation of a plot of land marked the shift from hunter-gatherer to grower. Agriculture allowed humans to stay in one place, build dwellings, and create a more stable culture. Humans no longer had to wander the earth in search of food. In our contemporary society, we take our food for granted and often chafe at remaining in one place. Travel has become a badge of the worldly, well-educated, and sophisticated person. But with peak oil and global warming were beginning to rethink our concept of travel and admit that were all going to have to stay home more often.
Even when Im grounded in my garden, movement is all around me the squiggly worms under my feet, the burrowing insects in the soil, and the leap of the toad out of the emerging asparagus plants. The very soil itself tells a story of travel through time and space, one more colorful or magnificent than I would ever find from an airplane window. If I could sink my bulb planter down through the many layers of soil in my garden, through layer upon layer of rock, I would hit Precambrian bedrock, one to two billion years old. Between that bedrock and my garden soil, the successive layers of rock contain fossils that document a land periodically covered by shallow seas.
Iowa, a state of destroyed prairies, is landlocked and largely treeless. I have to push my imagination to picture a landscape covered by ocean. Fossils in the Cambrian rocks, approximately 500 million years ago, depict a life limited to primitive forms: trilobites, algae, and brachiopods. About 450 million years ago, during the Ordovician Period, a warm, shallow inland sea once again covered the area. Sea sediment formed a diversity of rock types and supported the growth of algae and major invertebrate groups: corals, mollusks, and echinoderms.
When the seas retreated, erosion most likely shaped the land, removing some rock and marine sediments. But by the Devonian period, 413 to 355 million years ago, once again limestone, dolomite, and other rock types were formed from sediments of ancient seas. Vertebrate animals made their debut. Sharks and bony fish floated through the same waters as brachiopods and lower life forms. I lift my head in the garden and again I recognize the parallel. I watch the neighbors horse seemingly float across the pasture, racing with the wind at the same time that these lowly earthworms wiggle at my feet.
The Mississippian period, 355 to 310 million years ago, saw the last of the widespread ocean waters to wash across the interior of what is now the North American continent. The sediment rocks of this era, primarily limestone, contained rich quantities of fossils, particularly crinoids. The Mississippian seas finally receded and exposed a large, emergent landmass, once again open to weathering and erosion.
As I imagine this time period, I begin to glimpse the wide-open prairies to come, but without this winters ice storms and damaged limbs. Instead, Iowa had a tropical climate, more like present-day Trinidad and Tobago. Huge coal swamps covered much of southern Iowa during the Pennsylvanian period, 310 to 265 million years ago. A tropical or subtropical climate gave rise to a different set of species: scale trees, club mosses, seed ferns, cockroaches, snakes, and large amphibians. The region enjoyed a perpetual summer of warm, moist days, as shown by the lack of rings in the fossilized trees of the period.
Our tropical paradise didnt last. From the Permian to the Cretaceous periods, 265 to 130 million years ago, the warm, moist climate turned drier. Iowa was most likely above sea level, and the region is thought to have been a low arid or semi-arid plain. Again, shallow seas washed over the land, and deposits of shale, lignite, conglomerate and limestone formed the Cretaceous bedrock. Primitive coal-swamp plants were replaced by the forerunners of familiar trees that dominate today, such as magnolia, poplar, sassafras, and willow. Although dinosaur fossils have never been found in Iowa, this was the era when dinosaurs took to the land, water, and air. Fossils of gigantic flesh-eating reptiles and of giant turtles and crocodiles have been found in the state and can be traced to this period.
The toad who had taken up residence under my asparagus ferns moves toward my stand of horseradish. His thick brown body, perfectly camouflaged in my garden soil, is a time capsule from the Cretaceous period. But the Tertiary period, 65 to 2.5 million years ago, brought the biggest movement to the landscape, and ushered in a climate that is recognizable today. The North American landmass that had previously been located near the equator drifted slowly northward into its present-day location.
The climate became cooler, drier, and less stable. Humid, subtropical flora gave way to savannas and savanna-like parklands. Fossils of seeds and other plant materials, stuck in the jaws of an ancient rhinoceros, are the earliest known ancestors of todays prairie grasses. Fossils of other large mammals from the cat family to horned ruminants to camels suggest that the land was an open savanna similar to those found in Africa today.
Toward the end of the Tertiary, a huge shift began. The mean temperature of the region dropped and large masses of ice and snow moved southward from the North Pole, covering what is known today as the Midwest and the Great Plains. During the Ice Age, beginning 2.5 million years ago ending just 10,000 years ago, the temperatures warmed. The ice melted, then again moved southward over the land, over all the layers of bedrock that had been laid down since the Precambrian period. The glaciers deposited their till on top of the land, and these sediments sand, clay, and pebbles were left to weather and erode for tens of thousands of years. Undoubtedly, the till mixed with other wind-blown and water-borne particles to form what today we recognize as soil.
A year at home with my garden soil has brought me to a better awareness of the intense forces of nature moving all around me.
A year at home with my garden soil has brought me to a better awareness of the intense forces of nature moving all around me. The birds, the plants and invasive species, the very garden seeds themselves take their own routes to arrive here. The molecules of black soil, once rock, under my feet have been washed, battered, blown, ground, scraped, and scattered to their present site and size. Even the continent Im standing on was once somewhere else. And of course, the earth spins round and round on its axis, moving around the sun.
In the future, I predict that more of us will have to stay home and tend our gardens, as Voltaires Candide recommended at the end of his calamitous journey. In the face of our environmental crisis, we will have to rethink our desires to drive long distances or hop on airplanes. Our lives that have become global and international will remain so, but with more virtual travel, more virtual connections among people and places. Meanwhile, we will have a chance to lie down on our couches and contemplate Wordsworths flash upon the inward eye that is the bliss of solitude what we may have overlooked on our way to pay our long-term parking fee. We will have a chance to notice the sprightly dance of the wild from the lowly worm to the lofty bat, from the invasive parsnip to the beneficial toad. We will have a chance to experience our place on this revolving, ever-shifting planet, before it spins out of control.