Soils and climate of Cul de Sac Valley, Haiti: A soil water and geomorphology perspective

Abstract

Soil is an important natural resource, yet for many countries, including Haiti, the only soil inventory is a general soil map at 1:250,000 scale, which is not suitable for management planning at the farm level. A soil survey for a 3,000 ha (7,400 ac) segment of Cul de Sac Valley was conducted at 1:24,000 scale. Eleven soil types and soil map units were identified. Approximately 60% of the study area consisted of soils on Floodplains, while 40% were soils on Foothills, Hills, and Dissected Alluvial Fans. The combination of the parent material, predominantly marine sediment and limestone bedrock, and spatial-temporal precipitation patterns resulted in soils dominated by calcium carbonate (CaCO3) and sodium (Na) accumulations throughout their profile. The new soil geomorphology map derived from the detailed soil map was similar to the existing general soil map and geomorphology map. It was spatially more accurate and provided better understanding of soil and climate influence on soil water movement. Cul de Sac Valley resulted from uplifting and erosion and deposition processes. This, combined with aridic to semiaridic climate conditions, resulted in cemented CaCO3 accumulation and Na rich soils. The water management for irrigation was limited by a combination of soil properties such as high gravel and steep slopes for Dissected Alluvial Fans and Hills soil geomorphic units, presence of cemented CaCO3 for Foothills, and high Na content for Lower Flat Plains. Further studies are needed for a complete and comprehensive understanding of the soil geomorphology processes and climate interactions of this complex system.