During the colonial period, for three centuries, Peru exported only minerals, gold and silver, which in large quantities were extracted from the numerous mining centers of the Sierra (Hualgayoc, Cerro de Pasco, Yauli, Huancavelica, Castro Virreyna, Caylloma, etc..): direct export to Spain (via Panamá), which was enriched, while Peru benefited from it very little. In the century XIX profound changes occurred in the economy of the country, both because the largest and most accessible mineral deposits began to run out, and because the production of guano became increasingly important, especially between 1840 and 1875 (in this period the export of guano was the basis of the Peruvian economy), and that of sodium nitrate. The war against Chile of 1879-1883 caused Peru to lose the nitrate provinces and caused a terrible financial crisis, which for many years paralyzed the life of the republic, which recovered very slowly. Having discovered rich deposits of copper and oil, these replaced, in the export trade, the precious metals; in the last decades, some agricultural crops (sugar cane and cotton) were rapidly developing.
According to an investigation carried out in 1929 would agrarian cultivation places 1,460,000 hectares (just over 1% of the total area), of which 1 / 3 in the coastal area and 2/3 in the Sierra. Cotton, indigenous to Peru (the species Gossypium peruvianum), is cultivated in the irrigated oases of the coastal area, but it also finds good living conditions in vast areas of Montaña, where its cultivation could develop if there were no shortage of labor and quick and easy means of transport. Production began to be remarkable at the beginning of the twentieth century, and grew rapidly from one year to the next; it was 72,500 q. in 1899-1900, of 261,000 q. on average in the period 1909-10 / 1913-14, of 534,000 q. in 1926-27, of 490,000 in 1929-30, of 507,000 in 1930-31, of 526,000 in 1932-33. The cultivation of cotton covers a total of 126,880 hectares (of which 46% in the department of Lima and 29% in that of Ica) and employs about 40,000 workers; the largest production is given by the oases of Río de Chincha, Ica, Piura, Huaura, Chancay and Cañete. Tangüis, which has very white and long fibers and gives a product that is 25 to 30% greater than that of the other varieties and constitutes about 75% of the Peruvian product; followed by the varieties Egypto, Mitafifi (with long and silky cream colored fibers), Áspero (with rough fibers, very suitable to be mixed in fabrics with wool), Semi – áspero, etc. The Tangiüs variety is acquiring more and more land at the expense of the others. Approximately 90% of Peruvian cotton production is exported.
According to topschoolsintheusa, sugar cane, grown on 78,000 hectares (75% in the departments of Lambayeque, Libertad and Lima), yielded 4,220,000 q. in 1929-30 and 3.878.000 in 1930-31 (of which 3.300.000 exported), in comparison with the 684.000 q. produced in 1895-96 and with the 2,230,000 quintals of 1913-14. Cane is also grown in the irrigated coastal oases, where it is favored by the friable sandy soil, annually enriched with guano, by the high temperatures throughout the year, by the abundant sunshine. The average production per hectare ranges from 400 to 600 quintals, while it is only 200 quintals. in Cuba and 400 in Hawaii; but in those islands the harvest is annual, while in Peru the cane reaches maturity only after 18.20 months. The oases that give the greatest product are those of Chicama, north of Trujillo, and Lambayeque. In the coastal oases, especially in those of Pacasmayo, Chiclayo and Lambayeque, rice is also grown abundantly (54,000 hectares, 47% of which in the Lambayeque department and 23% in Libertad), whose production (1,362,000 quintals in the 1931-32) is however insufficient to meet the needs of the country. On the other hand, coffee gives a small quota to exports, also cultivated in the coastal region, but above all in the eastern valleys of the Sierra (del Perené, Chanchamayo, Paucartambo), where good fruit is also obtained from cocoa (in the Perené region 200,000 cocoa trees planted). On the highlands the prevalent crops are those of wheat (142,150 ha., Of which 20% in the department of Ancash, 20% in that of Cajamarca and 15% in that of Cuzco; produced about 1 million quintals per year), corn (which is the main food of the population; 280,400 hectares, of which 25% in the department of Cajamarca and 20% in the department of Ayacucho), potatoes (285,270 hectares: 51% in the Puno department) and barley (124.800 ha.), cultivated especially in areas above 3000 m. The Amerindians cultivate coca (departments of Cuzco, Ayacucho, Huánuco, etc.) on the eastern slopes of the Sierra, suitably terraced; the harvest of the leaves, which are then largely exported to Europe for the extraction of cocaine, is done four times a year. Cocaine factories are also found in the country, and they export around 1500 kg annually. of this alkaloid, almost exclusively in Japan. Other crops to remember are those of fruit trees (52,000 hectares; pear trees in the Urubamba valley,
La Montaña is rich in precious woods, such as cedar, mahogany and rosewood, but the exploitation does not matter because it is hampered by the lack of communication routes with the coast; the little wood that is exported goes down to Iquitos, where there are sawmills, and then follows the Amazon route. The production of rubber, once very important (between 1909 and 1919 they produced an average of 27,000 quintals per year), is now insignificant for the competition of the South Asian plantations; it is still collected in the valleys of Ucayali, Huallaga, Marañón, Napo, Javary and Putumayo. Iquitos is the center of relative trade.
Other products from Montaña are tagua (or vegetable ivory), consisting of the hard seeds of a palm tree (Phytelephas), balata, a substance similar to gutta-percha, extracted from a sapotacea, copaive balsam, extracted from Copaifera, sarsaparilla, cassia , ipecacuana and other medicinal extracts.