ACID SULFATE SOILS OF THE CARIBBEAN REGION—THEIR OCCURRENCE, RECLAMATION, AND USE

Abstract

Acid sulfate and related soils occur extensively in the Caribbean region in areas such as the Orinoco Delta, Guyana, Suriname, and Trinidad. The aerial extent of such soils is likely to exceed 1.5 million hectares. Included in the group are peaty soils, clay soils, and clay soils with buried organic layers. Most of the soils are essentially only extensively used for grazing at present. There have been attempts at more intensive agricultural development in Guyana, for example, but without adequate measures, failure and abandonment of reclaimed areas resulted. In Trinidad, partial reclamation, consisting of drainage of an area, caused major disruptions of the agriculture which was based on a wet season rice crop with vegetables in the dry season. Most acid sulfate soils in the region have a surface layer which does not qualify as a sulfuric horizon or as sulfidic materials. These features occur primarily in sub-soils. There has been little research on reclamation and more intensive agricultural use of acid sulfate soils in the Caribbean region. In some of the soils of Guyana and Trinidad, upwards of 50 tons per hectare of ground limestone are needed initially to appreciably reduce the effects of the high acidity which develops on draining, and the frequency and rate of future applications have not been worked out. Where dilute sea water is available and its use can be controlled, repeated flooding and draining of acid sulfate soils have been used for reclamation. However, due to the degree of water control needed, this method, although technically sound, has severe constraints.