Influences of Geographic Environment - Ellen Churchill Semple (libby ebook reader .TXT) 📗
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Terrace tillage is rare in new countries of extensive plains, like the United States and Canada, where the level lands still suffice for the agricultural needs of the people; but in the confined mountain basins and valleys which made up the Inca's territory in ancient Peru, every available natural field was utilized for cultivation, and terraces brought the obstinate mountain sides under the dominion of the Andean peasant. They were constructed, a hundred or more in number, rising 1000 or 1500 feet above the floor of the highland valley, contracting in width as they rose, till the uppermost one was a narrow shelf only two feet broad. These were extended by communal labor year after year, with increase of population, just as to-day in Java and the neighboring islands, and became the property of the Inca. Streams from the higher slopes were conducted in canals and distributed from terrace to terrace, to irrigate and fertilize. These terraces therefore yielded the best crops of potatoes, maize and pulse. The cultivable area was further extended by floating gardens, consisting of rafts covered with earth, which floated on the surface of lakes.1278 They existed in ancient Mexico also,1279 and are used to-day in the lakes and streams of Tibet and Kashmir1280 and the rivers of overcrowded China.
Mountainous islands, born of volcanic forces or the partial submergence of coastal ranges, have steep surfaces and scant lowlands. Their inhabitants command limited area at best. Driven to agriculture by their isolation, drawn to it by the favorable oceanic climate, such islands develop terrace tillage in its most pronounced form. On the precipitous pitch of Teneriffe, every particle of alluvial soil is collected to make gardens. Long lines of camels, laden with boxes of earth, may be seen coming almost daily into the town of Santa Cruz, bringing soil for the terraces.1281 This is desperate agriculture. Irrigated terraces scar the steep slopes of many Polynesian islands.1282 They are highly developed among the Malay Battaks of Sumatra, especially for rice culture.1283 In Java, Bali and Lombok they reach a perfection hardly equalled elsewhere in the world. In Java they begin at an altitude of 1000 feet, cutting main and branch valleys into amphitheaters, and covering hundreds of square miles.1284 On the volcanic slopes of Lombok the terrace plots vary from many acres to a few square yards, according to the grade, while a complete system of irrigation uses every brook to water the terraces. Here as in Java the work began at a very early period, when it was probably introduced among the native Malays by Brahmans from India.1285 Japan, two-thirds of whose area is mountainous, has terraced its steep valley walls often up to 2000 feet or more, and utilized every patch of ground susceptible of tillage.1286
A mountain environment often occasions a forced development in the form of agriculture among peoples who otherwise still linger in a low stage of barbarism or savagery. The wild, head-hunting Igorots, inhabiting the Cordilleras of north central Luzon, have levelled the face of their mountains into a series of platforms, held by retaining walls from twenty to thirty feet high. On these they cultivate upland rice at an altitude of 5000 feet. The Igorot province of Bontoc contains valleys in which every available foot of land is terraced for rice, and which present artificial landscapes vividly recalling Japan. Labor is the heritage of each inhabitant. Every man, woman and child down to ten years of age shares in the work of providing food.1287 Africa shows parallel cases. The Angoss people, a savage negro tribe who occupy part of the Murchison Range in northern Nigeria, have mapped out all their sloping land into little terraces, sometimes only a foot or two wide. One of their peaks, 4135 feet high, has its plateau top covered with populous villages, owing to the protection of the site, and every inch of its slope cut into terraces planted with millet and guinea corn.1288 A more primitive form of this tillage is found in the country of the Marunga negroes, who occupy the steep western face of the rift valley filled by Lake Tanganyika. Here Cameron found the surface not regularly terraced, but retaining walls of loose stones disposed at intervals, which served to hold the soil in place, without greatly altering the natural slope. The scene recalled the terraced heights of Switzerland, and the people working there looked like flies on a wall.1289 In the semi-arid country of Sudanese Darfur, where only the mountain districts are well watered and thickly populated, small terraces for grain and melons cover all the slopes.1290
Mountain agriculture is necessarily laborious. The paucity of arable land precludes the possibility of letting fields lie fallow. These, to prevent exhaustion, must be constantly and abundantly fertilized, all the more as conditions of excessive subærial denudation found in the steep slope and usual heavy rainfall of mountains, as well as possible glacial scouring of the land in the past, have greatly attenuated the layer of soil called upon to support plant life. The Swiss or Tyrolese farmer cherishes his manure pile as at once source and badge of his wealth. After harvest it is carted or carried in baskets not only to the terraces, but also to the wide alluvial fan that grows his oats and rye, to his meadows and hay fields. Both in Mexico and Peru the soil received a dressing of poudrette. Manuring was most extensive where population was densest, as in the isolated mountain valleys opening out upon the desert coast of Peru. Every kind of organic refuse was utilized, and fish was buried with the kernels of maize as a fertilizer. The deposits of guano found on the headlands and off-shore islands were used from the remotest times. Different guano beds were assigned to the several provinces, and the breeding places of the birds were protected by law.1291 Ashes and decayed wood were employed for the same purpose, or plants were dug into the soil, while human manure was in Mexico a marketable commodity as in China.1292
In all mountain regions where population has begun to press upon the meager limits of subsistence, level land and soil are at a premium. In ancient Peru space was begrudged for the dead.1293 Cities covered considerable space on the roomy intermontane plateaus; but in the narrow lateral valleys, houses and temples were built on rocks, in order to reserve every fertile spot for agriculture.1294 The traveler notices the same thing throughout the Alps. Compact villages cling to the mountain sides, leaving the alluvial hem of the stream or level glacial terrace free for the much needed fields. Only in broad longitudinal valleys, like that of Andermatt, do the settlements complacently spread out their skirts, or on wide alluvial fans where transverse valleys debouch upon the plains. The mountaineers of the Crimea construct their houses against the precipices, excavating into their face and building up the front, with stones, and thus reserve the gentler slopes for vineyards and gardens.1295 In the Kangra, Kumaon, and Garhwal districts of the British Himalayas, the large Indian villages of the plains give place to small hamlets or detached homesteads, scattered here and there wherever occasional patches of soil on a hillside or in a narrow valley offer hope of sustenance. These hamlets or dwellings are located on the sides of the mountains, because level spots which can be irrigated must be reserved for rice fields.1296 The high site is also freer from malaria.
In the high Himalayan province of Ladak or Western Tibet, this principle of land economy reaches a climax. All settlement is on the perpendicular. The abrupt mountain sides are honey-combed with tombs, villages and Buddhist lamaseries in the detached localities where population occurs. A pleasure walk through one of these Tibetan towns means a climb by steep flights of steps hewn out of the rock, varied by a saunter up ladders, where the sheer face of a cliff must be surmounted to reach the houses on a ledge above.1297 Pictures of these recall forcibly the cliff-dwellings of the Pueblo Indians. Even the important market city of Leh covers the lower slope of the mountain at an altitude of 11,500 feet, and from its height overlooks the cultivated fields in the sandy valley bed below, made fertile by irrigating streams from debouching cañons.1298 The Ladak villages always shun the plains. The desire to economize level arable land does not alone dictate this choice of sites, however; the motive of protection against inundation, when the snows melt and the streams swell, and also, to some degree, against hostile attack, is an additional factor. In the mountainous parts of overcrowded China, again, the food problem is the dominant motive. In the rugged highland province of Shensi, a village of several hundred people covers only a few acres, and rises in closely packed tiers of houses against the mountain side.1299 In the wilder, half-conquered parts of Sze Chuan the villages crown the lower peaks, cling to the base of the mountains, or are perched on ledges of rock overlooking the gorges. Among the steep cliffs bordering the upper Yangtze, occupied chiefly by the timid, displaced Mantze aborigines, at an altitude of 10,000 feet, small platforms resting on beams projecting from the sheer mountain face support minute houses, whose backs burrow into the cliff behind. The small children are tied to the door post, to keep them from falling into the millet field below. The house is accessible only by bolts driven into the cliff. Above and below is the farm—small patches of tilled soil, often not larger than a bath towel, to which the cultivator lowers himself by a rope.1300 Here life hovers on the brink of death and despair.
Paucity of arable land in mountain regions leads to the utilization of the untillable slopes for stock grazing. This industry is always a valuable ally to mountain agriculture on account of the manure which it yields; but in high altitudes, where the steepness or rockiness of the soil, cold and the brevity of the growing season restrict or eliminate cereal crops, it becomes the dominant occupation of the
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