underwrites much of the funding for expensive genetic studies.
Modified genes from commercially bred bentgrass, a turf used on golf courses, have been confirmed in native Oregon grasses, miles from the source. Assurances from the aquaculture industry that genetically supercharged salmon won’t breed with wild North American stock, because they’re raised in cages, are belied by thriving salmon populations in estuaries in Chile—a country that had no salmon until breeders were imported from Norway.
Not even supercomputers can predict how man-made genes already loosed upon the Earth will react in a near infinity of possible eco-niches. Some will be roundly trounced by competition toughened over eons by evolution. It’s a fair bet, though, that others will pounce on an opportunity to adapt, and evolve themselves.
5. Beyond the Farm
Rothamsted research scientist Paul Poulton stands in November drizzle, knee-deep in holly, surrounded by what will be around after human cultivation ceases. Born just a few miles up the road, lanky Paul Poulton is as rooted to this land as any crop. He started working here right out of school, and now his hair has whitened. For more than 30 years, he’s tended experiments that began before he was born. He’d like to think they will continue on long after he himself turns to bone dust and compost. But one day, he knows, the wild green profusion beneath his muddy irrigation boots will be the only Rothamsted experiment that will still matter.
It is also the only one that has required no management. In 1882, it occurred to Lawes and Gilbert to fence off a half-acre of Broadbalk—the winter-wheat field that had variously received inorganic phosphate, nitrogen, potassium, magnesium, and sodium—and leave the grain unharvested, just to see what would happen. The following year, a new crop of self-seeded wheat appeared. The year after that, the same thing occurred, though by now invading hogweed and creeping woundwort were competing for the soil.
By 1886, only three stunted, barely recognizable wheat stalks germinated. A serious incursion of bentgrass had also appeared, as well as a scattering of yellow wildflowers, including orchid-like meadow peas. The next year, wheat—that robust Middle Eastern cereal grown here even before the Romans arrived—had been entirely vanquished by these returning natives.
Around that time, Lawes and Gilbert abandoned Geescroft, a parcel about half a mile away, consisting of slightly more than three acres. From the 1840s to the 1870s, it had been planted in beans, but after 30 years, it was clear that even with chemical boosts, growing beans continuously without rotation was a failure. For a few seasons, Geescroft was seeded in red clover. Then, like Broadbalk, it was fenced off to fend for itself.
For at least two centuries before Rothamsted’s experiments began, Broadbalk had received dressings of local chalk, but low-lying Geescroft, hard to cultivate without digging drainage, apparently hadn’t. In the decades following abandonment, Geesecroft turned increasingly acidic. At Broadbalk, which was buffered by years of heavy liming, pH had barely lowered. Complex plants like chickweed and stinging nettle were showing up there, and within 10 years filbert, hawthorn, ash, and oak seedlings were establishing themselves.
Geescroft, however, remained mainly a prairie of cocksfoot, red and meadow fescue, bentgrass, and tufted hair grass. Thirty years would pass before woody species began shading its open spaces. Broadbalk, meanwhile, grew tall and dense. By 1915 it added 10 more tree types, including field maple and elm, plus thickets of blackberry and a dark green carpet of English ivy.
As the 20th century progressed, the two parcels continued their separate metamorphoses from farmland to woodland, the differences between them amplifying as they matured, echoing their distinct agricultural histories. They became known as the Broadbalk and Geescroft Wildernesses—a seemingly pretentious term for land totaling less than four acres, yet perhaps fitting in a country with less than 1 percent of its original forests remaining.
In 1938, willows sprouted around Broadbalk, but later they were replaced by gooseberry and English yew. “Here in Geescroft;” says Paul Poulton, unsnagging his rain parka from a bush bright with berries, “there was none of this. Suddenly, 40 years ago, holly started coming in. Now we’re overgrown. No idea why.”
Some of the holly bushes are the size of trees. Unlike Broadbalk, where ivy swirls up the trunk of every hawthorn and flows over the forest floor, there is no ground cover, save for brambles. The grasses and herbaceous weeds that first colonized Geescroft’s fallowed field are completely gone, shaded out by oaks, which prefer acidic soil. Due to overplanting of nitrogen-fixing legumes, and also to nitrogen fertilizers and decades of acid rain, Geesecroft is a classic example of exhausted soil, acidified and leached, with only a few species predominating.
Even so, a forest of mainly oak, brambles, and holly is not a barren place. It is life that, in time, will beget more.
The difference at Broadbalk—which has just one oak—is two centuries of chalk lime, which retains phosphates. “But eventually,” says Poulton, “it will wash out.” When it does, there will be no recovery, because once the calcium buffer is gone, it can’t return naturally unless men with shovels return to spread it. “Someday,” he says, almost in a whisper, his thin face scanning his life’s work, “all this farmland will go back to woody scrub. All the grass will disappear.”
Without us, it will take no more than a century. Rinsed of its lime, Broadbalk Wilderness will be Geescroft revisited. Like arboreal Adams and Eves, their seeds will cross on the winds until these two remnant woodlands merge and spread, taking all the former fields of Rothamsted back to their unfarmed origins.
In the mid-20th century, the length of commercialized wheat stalks shortened nearly by half even as the number of grains they bore multiplied. They were engineered crops, developed during the so-called Green Revolution to eliminate world hunger. Their phenomenal yields fed millions who otherwise might not have eaten, and thus also contributed to expanding the populations of countries like India and Mexico. Designed through forced crossbreeding and random mixes of amino acids—tricks that preceded gene splicing—their success and survival depend on calibrated cocktails of fertilizers, herbicides, and pesticides to protect these laboratory-bred life-forms from perils that lurk outside, in reality.
In a world without people, none will last in the wild even the four years during which wheat hung on in the Broadbalk Wilderness after Lawes and Gilbert abandoned it to the elements. Some are sterile hybrids, or they spawn offspring so defective that farmers must purchase new seed each year—a boon for seed companies. The fields where they are destined to die out, which are now most of the grain fields in the world, will be left deeply soured by nitrogen and sulfur, and will remain badly leached and acidic until new soil is built. That will require decades of acid-tolerant trees rooting and growing, then hundreds of years more of leaf litter and decaying wood broken down and excreted as humus by microbes that can tolerate the thin legacy of industrial agriculture.
Beneath these soils, and periodically disinterred by ambitious root systems, will lie three centuries’ worth of various heavy metals and an alphabet soup of POPs, substances truly new under the sun and soil. Some engineered compounds like PAHs, too heavy to blow away to the Arctic, may end up molecularly bound in soil pores too tiny for digesting microbes to enter, and remain there forever.
IN 1996, LONDON journalist Laura Spinney, writing in
Like the entire Earth, the posthuman fate of Britain teeters on the balance of these two visions: a return to temperate foliage, or a lurch into a tropical, super-heated future—or, ironically, into a semblance of something last seen in England’s southwestern moors, where Conan Doyle’s Baskerville hound once wailed into chill mist.
Dartmoor, the highest point in southern England, resembles a 900-square-mile baldpate with occasional
