AGRICULTURAL EQUIPMENT: PLOW, HARROW, SEED DRILL. INSET: THE ACTION OF THE PLOW TO SLICE AND TWIST OVER STRIPS OF TOPSOIL.
Immediately after the cataclysm you’ll hopefully have little trouble finding abandoned tractors and fuel to run them, with trailers sporting multiple plowshares. But once available fuel dries up or lack of spare parts stills the tractor, you’ll have to revert to less intensive methods. And it won’t simply be a case of finding some oxen and harnessing them to the modern plow, as these large multiple-bladed contraptions require enormous traction to rip them through the ground. If you can’t find a traditional plow—perhaps check museums in the nearby deserted cities—you will have to construct your own. You might be able to scavenge a modern plow blade from a trailer rack and remount it singularly on a frame, but if these have all rusted away, you could construct a wooden plow plated with cast iron, or rework scavenged steel panels in a forge. The plowshare is essentially a sharpened blade that horizontally undercuts the soil and forces it up over the moldboard, shaped to carefully roll the sod slice over and lay it back onto the field upside down.
After plowing, the resultant furrows and ridges must be smoothed down to prepare a seedbed ready for sowing. The harrow is as ancient as the plow, and alternative designs differ by how deeply they penetrate and how finely they break up clods for the tilth. Modern harrows use rows of upright metal disks to cut through the ground, or springy curved metal tines that vibrate up and down as they are dragged to pulverize the ground, mechanically mimicking the action of a hand-wielded rake. You can build your own simpler designs of diamond-shaped wooden frames with spikes sticking down, or even drag a heavy tree branch across the surface if you’re really stuck. Different crops prefer particular conditions of tilth; wheat, for example, likes a fairly coarse seedbed, with clods about the size of a child’s fist, whereas barley prefers a much finer tilth. Lighter harrowing is applied after sowing to cover the seeds, and can also be used between cultivated rows to tear up weeds.
Once an appropriate tilth has been prepared, the next step is to put seeds into the ground. The original meaning of “broadcast”—coined centuries before the invention of radio or TV—is scattering seeds far and wide, tossing them from a sack as you walk back and forth across the field. You can distribute seeds relatively quickly this way, but you have little control over their exact placement, which makes weeding later difficult. But again, with a little bit of ingenuity you can improve this process immeasurably. A seed drill is a mechanical seed sower. At its simplest, a cart has a hopper full of seed on top, and a chain of gears driven by one of its wheels that slowly turns a paddle at the bottom of the hopper chute to release a single seed at regular intervals. Each seed tumbles down a narrow vertical tube to be embedded at its preferred depth in the soil. Multiply the number of paddles and tubes in parallel and you can sow several rows in one pass, and tweaking the gear chain will alter the distance between plants in each row (you’ll find the optimum to use for different crops by experience). This system is much less wasteful of seed because with the optimized spacing, the growing plants do not compete with one another; nor do you waste space with excessive gaps. Moreover, arraying your crops in neat lines, rather than dispersed haphazardly by broadcasting, allows you to more easily weed between the rows. With a little more sophistication, a seed drill can also be constructed to deposit a small dollop of liquid manure or fertilizer into the seed hole, thereby helping every sprout establish itself.
THE PLANTS WE EAT
Agriculture is all about exploiting a stage in the life cycle of the plants we’ve adopted as crops. Many plants have adapted a particular part of their structure to act as a storehouse for their captured sunlight energy, to be used either by themselves the following year or as an inheritance for the next generation, their seeds. These stores are precisely the succulent and nutritious parts that you will be familiar with on the supermarket shelves. Most of the root and stem vegetables we eat are biennials—they bloom in their second year. Their reproductive strategy is to hoard a season’s worth of accumulated energy, stashed away in a specially enlarged section, remain dormant over winter, and then capitalize on their stockpile early the following spring to produce flowers and seeds well ahead of competitors. Examples of swollen taproots include carrots, turnips, rutabagas, radishes, and beets. By cultivating these strains and harvesting the bulging portions, we’re essentially raiding the energetic savings account they’ve diligently built up over the growing season. Potatoes aren’t actually a root vegetable, and the tuber we eat is in fact a swollen section of the stem. Other plants use specialized leaves as their energy storehouse—onions, leeks, garlic, and shallots are all tight clumps of thickened leaves. Cauliflower and broccoli are actually immature flowers and will become inedible if not picked early enough. Fruits are obviously the energy repository for a plant’s seeds, such as the succulent flesh enveloping the pit of a plum; the grain of cereal crops such as wheat is also botanically a type of fruit.
As humanity gave up its nomadic lifestyle and became established in settlements, rooted to a particular locale with surrounding agricultural fields, we became utterly dependent on reliable harvests from the plants we adopted as crops. But we’ve not been content to gratefully accept the nutritious plant stores that natural selection has provided. Over many generations of selective breeding, choosing which plants to propagate on the basis of certain desirable characteristics, we’ve tuned their biology to emphasize certain qualities and diminish unwanted traits. In the process of hacking these plants’ reproductive strategies to subvert them to our own purposes, we’ve distorted their biology so much that they are now as reliant upon us for their survival as we are upon them for our own. Every crop we grow today, from the grotesquely swollen tomato to the stunted and top-heavy rice plant, is a technology in its own right, the product of ancient genetic engineers.*
THE MOST IMPORTANT CEREAL CROPS: (TOP) WHEAT, RICE, CORN (MAIZE), BARLEY; (BOTTOM) OATS, RYE, MILLET AND SORGHUM.
There is an enormous diversity of edible plant species around the planet, and even though only a tiny fraction of these have been chosen for cultivation and selectively bred over millennia by civilizations throughout history, there are still an estimated 7,000 cultivated strains. However, only a dozen species account for more than 80 percent of global crop production today, and the major civilizations of the Americas, Asia, and Europe were built on just three staple crops: corn, rice, and wheat, respectively. These three plants will be just as critical to rebooting after the apocalypse.
Corn, rice, and wheat, as well as barley, sorghum, millet, oats, and rye, are all cereal crops: varieties of grass. This dominance of cereals in our diets, coupled with the fact that much of the meat we consume comes from livestock fed by either grazing in pastures or on grain fodder, means that much of humanity subsists, either directly or indirectly, by eating grass. And it is on this hugely significant category of crops that survivors will need to focus.
While the harvesting of many crops is pretty straightforward and intuitive—potatoes dug out of the sod, onions plucked off the surface, and apples picked from the boughs—getting cereal grain out of the field and processed for the table is a little more involved. Harvesting maize is as simple as walking along the rows with a sack slung to your back and plucking the cobs off the stalks, but the grain of other cereals is more finicky to remove. The no-fuss method is simply to chop down the entire plant and recover the grain away from the field. The tools for reaping are the sickle and the scythe. The sickle is a short curved blade, sometimes serrated, on a handle, and is used to slice through the stalks as the other hand gathers them into bunches. The scythe is a larger, double-handed tool composed of a long pole with two grips and a gently curved blade, around a yard in length, projecting out at a right angle. Wielding a scythe takes more practice, but it is held with straightened arms, and the blade is swept horizontally over the ground in a steady rhythm by smoothly twisting the whole body. The fel
led stalks are tied into bundles, and these sheaves are leaned upright against one another to dry in the field, then brought inside barns before the autumn rains.
After collecting the harvest—literally reaping what you sow—the next step is to separate the grain from the rest of the plant. This is called threshing, and the simplest way is to lay the harvest out on a clean floor and beat it with a flail—a long handle with one or more shorter sticks attached at the end with leather or chain hinges. Small-scale mechanical threshers rely on exactly the same basic principle, using a spinning drum covered with pegs or wire loops that fits tightly inside a round casing to strip grain from its stalk as it passes around the gap, and sieve out the grain through a grating at the bottom.
This threshing process leaves all the grain mixed in with the empty husks, and you must now separate the wheat from the chaff (it’s amazing how many everyday phrases derive from agriculture, the only vestigial link many of us retain from our heritage of working the land). The process is called winnowing, and your low-tech option is to simply toss the threshed material into the air on a windy day—the lighter chaff and straw are carried a short distance away on the breeze and the dense grain falls more or less straight back down. Modern machinery creates its own artificial wind using an electric fan, but relies on the same millennia-old principle.
As your post-apocalyptic society recovers and the population grows, one of the most crucial inventions for improving the efficiency of agriculture, producing maximum food with minimum human labor, and enabling a populous city-dwelling civilization is one that integrates these various processes. Combine harvesters today allow a single farmer to process twenty acres of wheat every hour—around a hundred times faster than reaping by hand with a scythe. A horizontal serrated blade mechanically replicates the action of the hand sickle, sawing side to side to cut the stalks as they are dragged over the front of the machine by a large cylinder of rotating paddle arms. The basic design hasn’t changed in almost two centuries, and the first horse-drawn mechanical reapers look surprisingly similar to their modern descendents. The combine harvester is undoubtedly one of the most important inventions of recent history, freeing so many of us from being required to work in the fields and enabling us to perform other roles in a complex society.
RUDIMENTARY MECHANICAL REAPER WITH SWEEPING ARMS (A) AND LOW, SICKLE-LIKE SERRATED BLADE (B).
NORFOLK FOUR-COURSE ROTATION
As long as you can grow grain for yourself, along with some other fruits and vegetables for the sake of nutritional balance and a more interesting diet, you’ll never starve to death. You could, of course, always hunt for meat, but keeping livestock, and sacrificing some of your arable capacity to support them, actually contributes a critical function for keeping your fields productive. As we’ve seen, without chemical fertilizers farmland would deteriorate in fertility, but animal manure allows you to return nutrients to the soil. Furthermore, there is a particular class of crops that will naturally boost soil nitrogen levels for you, the incorporation of which was a crucial step in the agricultural revolution in the seventeenth century. In the immediate post-apocalyptic world, the husbandry of plants and of animals will once again become inseparable, mutually supporting endeavors.
Throughout the Middle Ages, European farmers followed an agricultural convention of routinely leaving plots fallow—a woefully inefficient practice, as at any one time up to half of your fields would be growing no crops at all. Medieval agriculturalists recognized that their land became tired and its productivity plummeted if cereals were grown on it season after season, but they didn’t understand what caused this and could only attempt a solution by resting the ground for a year. We now understand that this drop in fertility is due to the loss of plant nutrients, which is why modern agriculture is so dependent on the liberal smearing of artificial fertilizers. This solution will be closed to you for the immediate aftermath, and you’ll need to revert to an older solution to the problem.
The key is that while most crops plunder nitrogen from the ground, some plants inject this vital nutrient back into the soil as they grow. This family of astounding plants is the legumes, which includes peas, beans, clover, alfalfa, lentils, soy, and peanuts. By plowing a crop of legumes back into the soil at the end of the season, or feeding them to livestock and using their manure to fertilize the land, vital nitrogen is captured and restored to the land. The incorporation of this fertility-pumping capability of legumes transformed agriculture and set Britain on course for the Industrial Revolution.
Varying between legumes and other crops on a plot of land will therefore maintain the productivity of the soil. But rather than simply swapping back and forth between two—from clover to wheat, say—a far better option is a crop rotation with several stages, as it also breaks the cycle of diseases and pests. These are often very specific to the plant they can attack, and so annually shifting, and not growing the same crop on a plot for several years, means that you can exert natural control without pesticides.
The Norfolk four-course rotation is the most successful of these historical systems and became widespread only in the eighteenth century, spearheading the British agricultural revolution. In the Norfolk system, succession of crops through each plot follows the order: legumes, wheat, root crops, barley.
As we have seen, growing legumes is intended to build up the soil’s fertility for the rest of the cycle. Clover and alfalfa grow well in the British climate, but in other regions you might be better off with soy or peanuts. At the end of the season, if you’re not harvesting any part of the plant for human consumption, the entire crop can be grazed by livestock or simply plowed back into the ground as green manure. The year after the legume course you want to plant a crop of wheat to capitalize on the soil fertility and produce your staple cereal for human consumption.
Don’t leave the field fallow the following year, but plant a crop of a root vegetable such as turnip, rutabaga, or mangold wurzel (field beet). One of the main purposes for leaving a field fallow in the Middle Ages—to plow and harrow it in spring but leave it unplanted for a year—was to kill off weeds in preparation for the next season. But with a root vegetable, you can plant a crop and still be able to rip out weeds between the rows. This course will yield you another crop, but rather than intending all of it for your own consumption—unless the crop is potatoes—you can use it to feed the animals. Your livestock will fatten up more quickly and will also produce more manure that you can spread back onto the field to preserve its fertility. By feeding your livestock a purpose-grown fodder, rather than simply letting them forage and browse grass for themselves, you also free up pastureland, which can now be used to cultivate even more crops.
Indeed, the adoption of the humble turnip and other root crops for fodder heralded a revolution in medieval agriculture. Not only are these more effective than grazing for fattening up livestock over the summer, but they also provide a reliable energy-rich feed throughout the winter. Before their introduction, every late autumn medieval Europe witnessed the mass slaughter of livestock, as there was simply insufficient food to keep the animals from starving before spring. Turnip, as well as other fodder crops like rutabaga, kale, and kohlrabi, are biennial plants, which means they can be left in the ground over winter and plucked out to feed cattle when needed. Used to supplement the energy-poor roughage of hays and silage (fermented grass), these nutritious fodder crops support large herds of livestock through winter, continuing not only the supply of fresh meat, but also providing fresh milk and other dairy products. These are a vital source of vitamin D over the dark winter months when your skin cannot synthesize it from sunlight.
The last phase in the rotation is the planting of barley, which you can again use to feed your livestock—but remember to keep back a portion for brewing beer (as we’ll cover in the next chapter). After the barley course, the rotation loops back to the beginning with the cultivation of legumes to restore the fertility of the soil and make it re
ady for the nitrogen-hungry cereal crop. So the rotation system is a harmonic coupling of the requirements and products of both plants and animals, it naturally combats pests and pathogens, and it allows the recycling of nutrients back into the soil. This particular system of crops won’t work universally, and you’ll need to find a set suited to your local soils and climate.* But the two key principles of the rotation system will ensure that you can reliably feed yourself and maintain soil productivity without exogenous chemical fertilizers after the apocalypse: alternate legumes with cereals, and grow root crops not for your own consumption, but specifically for your livestock. Reverting to small-scale methods, five acres of land will be enough to support a group of up to ten people: wheat for bread, barley for beer, a diverse range of fruits and veggies, as well as cattle, pigs, sheep, and chickens for meat, milk, eggs, and other products.
MANURE
Spreading animal manure helps fertilize the fields, but could you exploit human waste in the same way for post-apocalyptic farming? The challenge of agriculture without modern artificial fertilizers is how to turn feces back into food (crap into crop) as efficiently as possible, and ideally you would be able to close the loop on human consumption and ensure that precious nitrogen is not lost.
At the time when the open gutters in the streets of European cities were overflowing, Chinese cities were diligently collecting their waste, not with underground sewage pipes but with buckets and carts, and spreading it on surrounding fields. Each of us produces roughly 100 pounds of feces, and around ten times as much urine, every year—waste that contains enough nitrogen, phosphorus, and potassium to fertilize crops to yield around 450 pounds of cereals.
The Knowledge: How to Rebuild Our World From Scratch Page 7