Rubber and the Making of Vietnam: An Ecological History, 1897–1975 (Flows, Migrations, and Exchanges)

by Michitake Aso

The focus of the concessionary rush was terres gris and terres rouges, terms which were as much political, economic, and cultural constructions as they were classifications of the physical and chemical properties of soils. These characteristics, however, played an important role in promoting terres gris and terres rouges as valuable commodities, encouraging investment, and managing the land. The first region, terres gris, was located for the most part close to Sài Gòn. These soils were sedimentary in origin and contained a high percentage of sand. This sand content meant that these soils drained well and were less exposed to malaria, as the habitats favored by Anopheles mosquitoes, carriers of malaria plasmodia, were less common. With a high silicate content, these soils also had a lower cation-exchange capacity (i.e., the ability to store positively charged nutrients such as potassium, phosphorus, etc.) than the terres rouges and were therefore more easily exhausted by the growth of plants with a high nutrient demand, such as tobacco. Often these soils were used for wet-rice agriculture, which recycled many of the essential micro- and macronutrients.