That the soils of the Tibetan Plateau exist at all is remarkable. This vast island in the sky is, in planetary history, so new, so high and still rising skyward, so unconsolidated and prone to quake, so raked by gales and blizzards, it is a miracle that soil exists.
Yet the soils of the Tibetan Plateau sustain huge herds of migrating gazelles and antelopes, millions of yaks, sheep and goats cared for by nomadic pastoralists, and an entire Tibetan civilisation. Not only does a rich soil sustain life, the hardy grasses and sedges of the vast plateau pasture lands in turn protect the soils from the powerfully erosive forces of wind, snowstorms and intense cold. Neither permafrost below nor the sudden hailstorms from above disturb those soils, aerated by burrowing mammals, held together by the biomass of living plants, most of which is underground.
Tibetans have long known and respected the earth, and its innumerable local gods and spirits, which can cause earthquakes, landslides and floods if not treated with respect. Offerings are made daily to these local protectors, starting with a sprig of juniper put onto the morning fire to produce fragrant smoke.
The entire plateau is at an average altitude of 5000 metres in upper Tibet, in the arid west, and 4000 metres in the forested and wetter east; with the mountain ranges that enclose the plateau soaring far above. It is only on the mountain slopes that there is little or no soil, above the snowline. In Tibet the snowline is at 5000 metres, sometimes as much as 6000 metres, much higher than elsewhere, because Lhasa is no further from the equator than Shanghai, Mecca, Johannesburg, Tehran or Houston. Intense sun, intense inner continental winds, intense summer heating and winter cooling make for intensive erosion, so great that the entire yellow earths and Yellow River of northern China are the result of a Tibetan Plateau that erodes as fast as it uplifts. Yet despite these elemental forces, the soils sustain verdant alpine meadows for wild and domestic herds alike, and the millions of nomadic pastoralists who annually gather what nature provides.
Those soils regulate the flow of the great rivers of Asia, from Pakistan’s Indus, through Southeast Asia’s Mekong, to the Yangtze and Yellow of China. They absorb the summer monsoons and the icemelt from the glaciers in the snowmountain peaks, acting as a sponge that both soaks up and releases water through the year.
Across northernTibet there are no big rivers. This is a land of lakes, abodes of goddesses, slowly shrinking over recent millennia as the entire plateau becomes drier, only to start rising again very recently, due to climate change accelerating the melting of the glaciers.
Wetland soils are common, great peaty marshlands where migratory birds nest and feed, reeds grow thickly and yaks tread delicately tussock to tussock, fattening on the rich herbage. Hard ungulate hoofs seldom compact these springy soils, because the nomadic pastoralists know well that grazing must be done with a light touch, always moving the herd on well before the grass is exhausted. A mobile civilisation was guarantor of healthy soil and the protective plant cover.
Why the switch to past tense? The encroachment of modernity onto the Tibetan Plateau, over the past 65 years, has failed to understand any of the above. The modernisers, from intensively-cultivated lowland China, insisted the Tibetan Plateau could be made more productive, and that started with making the nomads build walls, of soil, of upturned sod, cutting the living turf to make fences running up and down hillsides, for “scientific management” of livestock. Further cutting into the soil was required to build highways, cities, hydro dams, power pylons, pipelines, railways, and to experiment with ploughing the grassland for crops. Herd sizes grew greatly, beyond the capacity of the soil to sustain them, while the pastoralists were allocated fixed lands, restricting their mobility, intensifying the impact of hooves and teeth on tightly fenced plots.
The result is widespread land degradation and even desertification. When the soil is stripped bare, Chinese scientists call it “black beach”, for which there is no cure, short of waiting thousands of years for soil to form naturally all over again. Bare rock is the final stage of a tragedy that need not have happened, a tragedy intensified by blaming the pastoralists themselves for recklessly overstocking and overgrazing, as if they are ignorant, unskilled herdsmen with no knowledge and no concern for the consequences of their actions. The victims of foolish policies designed in distant cities take the blame, and now must leave their ancestral lands and soils, to live in concrete peri-urban dependence on official handouts.
Scientists also declared war on the burrowing rodents of the grasslands, the pika and marmots which aerate the soil, keystone species which in turn feed many predators of the air and land. They have been poisoned en masse, blamed for soil degradation, although their population explosions are more the result than the cause of degradation.
Now China faces a major decision, whether to drown the water meadows of Dzoge, where the Chinese provinces of Qinghai, Sichuan and Gansu meet, under a torrent of water diverted from the upper Yangtze River, in a grand canal scheme intended to deliver water to northern China. The Dzoge wetland is on the great bend of the Yellow River as it rounds the sacred Amnye Machen mountain range. It is at last recovering from misguided attempts to modernise it by digging drainage ditches everywhere, drying wetland into fire-prone peatland that starves the grasses of the water they need. It was these water meadows that gave the People’s Liberation Army its worst moments, in the Long March of 1935, as soldiers, unfamiliar with the marshy soils, failed to step only on tussocks, got mired and died. Ever since, Dzoge (Ru’ergai in Chinese) has been seen as treacherous, to be tamed, initially by drying it out. Now the plan is to blast tunnels and canals across eastern Tibet, capturing several major tributaries of the Yangtze River (Dri Chu in Tibetan) to be poured into the Yellow River at Dzoge, inundating the water meadows. As the International Year of Soils ends, China’s 13th Five-Year Plan is due to begin, in 2016. It is during the Year of Soils that the decision on this megaproject will be finalised.
Tibet’s soils have sustained the barley farmers of the valleys and the pastoralists of the open grasslands for thousands of years, because the Tibetans practiced eco-agriculture, with a light touch. They understood that highland soils are readily disturbed, and once the steppe is broken, the soils quickly erode. They always moved on, not lingering. That customary wisdom has been supplanted by a modern insistence on extremes: firstly on intensive meat production that overused the land and soil; now on grazing bans to somehow conserve watersheds.
Modernist intensive land use is unsuitable for the soils and the livelihoods of Tibet; while the traditional extensive land use, spread out across the landscape, respected the upland soils and the local gods.