Previous Soil Surveys

The earliest soil survey known for the area is the pioneering reconnaissance of the Canal Zone and its environs by Bennett (1926 & 1929).  He mapped the whole of BCI as the Frijoles red clay, with a topographic subdivision for the central plateau.   He admitted that the separation of the moderately fertile red clays derived from intermediate lithologies in Panama was problematic.  He noted that the clastic sedimentary formations contain much volcanic material and that their soils – the Gatun clays – are morphologically similar to the Frijoles clays, as are the Arraijan clays derived from calcareous sedimentaries.

BCI is covered by a soil survey of the Canal area (Catapan, 1970) for the Comision de Reforma Agraria (CRA) of the Ministerio de Desarollo Agropecuaria (MIDA).  The general map (1:100 000) shows the whole of BCI as ‘Red Mountain Soils’, where ‘mountain’ presumably means upland and non-alluvial rather than montane.  BCI is also covered by 1:20 000 soils maps from the same study.  These are held at the Comision’s office in Santiago, and were made readily available by MIDA staff for inspection and copying.  We have lodged hard copies of the Catapan 1:20 000 sheets covering BCI with STRI and the University of Potsdam.

The Catapan maps appear to be based mainly on the interpretation of aerial photography of unknown scale and dating from the mid-1960’s, with limited field checking. The mapping units are parametric compilations that incorporate: topsoil and subsoil diagnostic horizon designations according to the USDA Seventh Approximation (Soil Survey Staff, 1960); profile drainage; textual class; depth class; parent material group; slope gradient class; erosion class; stoniness class; and an evaluation of the land’s potential capability using a system similar the eight class hierarchy then employed by USDA (Klingebiel & Montgomery, 1961). The Catapan mapping units are therefore of land sensu lato, rather than just soils.

The boundaries generally accord with our findings, and clearly separate the dipslope plateau from the more rugged Bohio scarp terrain, the sedimentary, and volcanic lowlands. Other similarities include the recognition of the subsoils on the Bohio scarplands as cambic, compared to the oxic subsoils elsewhere.  Differences from our mapping and characterisation include their omission of smectitic mineralogy and impeded drainage on the Caimito marine facies, designation of the Bohio scarpland soils as having worse drainage than the rest of the island, and differentiation of umbric (dark) topsoils on the plateau compared with ochric (lighter coloured and less organic) topsoils elsewhere.

Other pedospatial data

Although not primarily pedological, investigations in several disciplines have collected data that contribute to understanding of the soil cover of BCI.  The soils interest was tangential and primary soils data were zero/slight in many studies.

Those with more substantial soils data or discussions are summarised in Table 3.1. The list is incomplete and we welcome information on omissions and errors.

Previous data on soil cover of BCI