Agriculture in Yucatan is, as elsewhere, dependent on the distribution of soils. The general pattern of the karstic plain that makes up the northern part of the peninsula consists of mounds and depressions (2-10 m difference in elevation). The mounds are bedrock outcrops containing small solution channels. The depressions are dolines formed through subsidence. In general, there are shallow black soils on the mounds and deep red soils in the depressions. The black soils are rich in organic matter, calcium, and phosphorous. The red soils have high contents of Si, Al and Fe oxides, and hematite and boehmite (Bautista & Zinck 2010:2-4). I may add that Prehispanic residential buildings tend to be found on the “mounds” (sometimes they are the mounds themselves). The depressions were usually used for agriculture.
Ethnopedology is the study of how soils and soilscapes are perceived, conceptualized and symbolized in local communities. Few researchers have compared the Maya soil nomenclature with the World Reference Base for Soil Resources (WRB). Bautista and Zinck (2010) have compared these classifications throughout the state of Yucatan.
The Maya soil classification (MSC) is based on key properties of soils in the northern Maya lowlands, such as ”relief position, rock types, size and quantity of stones, color of topsoil, depth, water dynamics, and plant-supporting processes. The MSC addresses the soil properties of surficial and subsurficial horizons, and uses plant communities as qualifier in some cases” (Bautista & Zinck 2010:1).
The northern part of the state of Yucatan may seem homogenous but when it comes to soil distribution it is very heterogeneous. Six Maya soil reference groups (MRGs) were found within a surface area covering only 1350 sqm. The soils are more homogenous in the southern part of the Yucatan state. In the Puuc region we find some of the best soils and they usually occupy large areas (Bautista & Zinck 2010:5).
Bautista and Zinck classify the soils according to the following criteria: (1) soils with limited rooting space because of rockiness and/or stoniness at shallow depth, (2) soils influenced by water and poor drainage conditions, (3) soils with color contrast between surface and subsurface horizons (such as K’an kab lu’um), (4) soils without color contrast between surface and subsurface horizons (Chak lu’um), and (5) sandy soils (Bautista & Zinck 2010:7f). Intensive milpa (swidden agriculture) is practiced only on K’an kab lu’um and Chak lu’um soils. Stony soils have greater planting distance (Bautista & Zinck 2010:10).
Bautista, Francisco and J Alfred Zinck (2010). Construction of an Yucatec Maya soil classification and composition with the WRB framework. Journal of Ethnobiology and Ethnomedicine 6 (7), 1-11.