The Big Ratchet: How Humanity Thrives in the Face of Natural Crisis by Ruth DeFries Page A
Authors: Ruth DeFries
Ads: Link
to eatand are tame enough to do the work, it’s a way out of the energy conundrum. The caloric surplus made ancient cities viable. Animal labor was pushing societies through the bottleneck to convert the sun’s energy into edible form.
Ancient China Sidesteps the Bottlenecks
Ancient Chinese society found ingenious ways around both conundrums of settled life: how to keep soils fertile and how to supplement human labor with more energy. By the beginning of the Common Era, farming had expanded way beyond the floodplains where civilization had taken hold. Land was scarce. Without new territory to clear, the settled Chinese had little choice but to abandon slash-and-burn farming. People had concentrated in cities, magnifying the conundrums of settled life and creating a self-perpetuating cycle between the demands of a growing population and new innovations that enabled it to grow further. The system they ultimately devised led Justus von Liebig to later claim, “The Chinese are the most admirable gardeners and trainers of plants, for each of which they understand how to prepare and apply the best-adapted manure. The agriculture of their country is themost perfect in the world.”
Liebig’s notion of Chinese agriculture refers to their sophisticated mimicry of the nitrogen and phosphorus cycles to resolve the soil-fertility conundrum. By perhaps 3,000 years ago, the Chinese had figured out that clover, soya beans, and adzuki beans enriched the soil and boosted rice yields. They were calling on the services of Rhizobium bacteria that live on the roots of these legumes to break apart the bond in nitrogen gas. The leguminous plants, when plowed under or stored to apply later, helped to keep nitrogen in the soil and millions fed in the growing empire. About a millennium later, Chinese farmers were rotating crops: one season millet or another grain, the next season soya or another legume,then maybe sesame or some other oil crop. The rotations replenished nitrogen and kept yields high.
The ancient Chinese had another key strategy for feeding large numbers of people. They followed the basic principle of the planetary machinery, recycling nutrients in a continual loop from soil to plants to animals and back to the soil. They used water buffalo, oxen, goats, pigs, and all their other domesticated animals as grand recycling machines. The animals produced manure that was rich in nitrogen, phosphorus, and other nutrients. Microbes took over to recycle the nutrients in manure back into the soil so the crops could grow again. The animals ate the leftovers from the crops in the field. On it went. Collecting the manure and bringing it back to the fields kept the cycle going.
The ancient Chinese didn’t waste even the nutrients in human excrement. Their organized systems for collecting human waste from people living in cities—euphemistically termed “night-soil”—as well as all manner of food scraps and other wastes, were unrivaled. So intently did the Chinese recycle night-soil that Victor Hugo wrote in Les Misérables that “not a Chinese peasant goes to town without bringing back with him, at the two extremities of his bamboo pole, two full buckets of whatwe designate as filth.” They recycled nutrients from all kinds of sources, dredging sludge from canals, for example, and spreading it on the fields to achieve the same effect as the great rivers that depositednutrient-rich soil on the floodplains. Over the centuries they perfected these systems, with different mixtures of waste applied to different crops—ash to legumes and nutrient-rich pig andhuman waste to vegetables. Their highly organized social and political systems went hand in hand with the sophistication of their agriculture, as did the complex waterworks they used to bring water to fields. The plains prospered, withcanals to channel water. Bamboo rigs with iron drill bits could reach deep stores of waterthousands of feet below the ground. Farming was not confined to
Ancient China Sidesteps the Bottlenecks
Ancient Chinese society found ingenious ways around both conundrums of settled life: how to keep soils fertile and how to supplement human labor with more energy. By the beginning of the Common Era, farming had expanded way beyond the floodplains where civilization had taken hold. Land was scarce. Without new territory to clear, the settled Chinese had little choice but to abandon slash-and-burn farming. People had concentrated in cities, magnifying the conundrums of settled life and creating a self-perpetuating cycle between the demands of a growing population and new innovations that enabled it to grow further. The system they ultimately devised led Justus von Liebig to later claim, “The Chinese are the most admirable gardeners and trainers of plants, for each of which they understand how to prepare and apply the best-adapted manure. The agriculture of their country is themost perfect in the world.”
Liebig’s notion of Chinese agriculture refers to their sophisticated mimicry of the nitrogen and phosphorus cycles to resolve the soil-fertility conundrum. By perhaps 3,000 years ago, the Chinese had figured out that clover, soya beans, and adzuki beans enriched the soil and boosted rice yields. They were calling on the services of Rhizobium bacteria that live on the roots of these legumes to break apart the bond in nitrogen gas. The leguminous plants, when plowed under or stored to apply later, helped to keep nitrogen in the soil and millions fed in the growing empire. About a millennium later, Chinese farmers were rotating crops: one season millet or another grain, the next season soya or another legume,then maybe sesame or some other oil crop. The rotations replenished nitrogen and kept yields high.
The ancient Chinese had another key strategy for feeding large numbers of people. They followed the basic principle of the planetary machinery, recycling nutrients in a continual loop from soil to plants to animals and back to the soil. They used water buffalo, oxen, goats, pigs, and all their other domesticated animals as grand recycling machines. The animals produced manure that was rich in nitrogen, phosphorus, and other nutrients. Microbes took over to recycle the nutrients in manure back into the soil so the crops could grow again. The animals ate the leftovers from the crops in the field. On it went. Collecting the manure and bringing it back to the fields kept the cycle going.
The ancient Chinese didn’t waste even the nutrients in human excrement. Their organized systems for collecting human waste from people living in cities—euphemistically termed “night-soil”—as well as all manner of food scraps and other wastes, were unrivaled. So intently did the Chinese recycle night-soil that Victor Hugo wrote in Les Misérables that “not a Chinese peasant goes to town without bringing back with him, at the two extremities of his bamboo pole, two full buckets of whatwe designate as filth.” They recycled nutrients from all kinds of sources, dredging sludge from canals, for example, and spreading it on the fields to achieve the same effect as the great rivers that depositednutrient-rich soil on the floodplains. Over the centuries they perfected these systems, with different mixtures of waste applied to different crops—ash to legumes and nutrient-rich pig andhuman waste to vegetables. Their highly organized social and political systems went hand in hand with the sophistication of their agriculture, as did the complex waterworks they used to bring water to fields. The plains prospered, withcanals to channel water. Bamboo rigs with iron drill bits could reach deep stores of waterthousands of feet below the ground. Farming was not confined to
Similar Books
