Homogeneous groups of soils from the area dedicated to the cultivation of sugar cane in the Cauca River valley (second approximation)

The sugar sector has had a semi-detailed study of soils in the flat part of the Cauca River valley since 1980. This study was carried out by the Agustín Codazzi Geographic Institute (IGAC) in collaboration with the Regional Autonomous Corporation of the Cauca Valley (CVC) and facilitated the characterization of soils used for sugar cane production in this inter-Andean valley. However, the focus of the research on site-specific agriculture given by Cenicaña required greater precision in terms of knowledge of soil properties and created the need for detailed soil studies in order to define increasingly reliable and specific sugar cane management systems.

In the detailed soil studies carried out in 216,765 hectares of the flat part of the Cauca River valley, 238 consociations or soils corresponding to seven taxonomic orders were identified, which indicate the edaphic variability of the region and the convenience of grouping the soils with the following objectives: (a) to identify and characterize the agroclimatic areas dedicated to sugarcane production; (b) to define homogeneous groups of soils to select experimental sites; (c) to facilitate the extrapolation of research results to soils that make up the same homogeneous group and (d) to define the management of the different soil groups through successive approximations according to the agroclimatic conditions of the areas where they are located.

Of the total area devoted to sugarcane production, only 10% exhibits textural heterogeneity across the profile horizons; the remaining 90% exhibits textural homogeneity and a predominance of the very fine clayey, fine clayey, fine loamy and coarse loamy textural families. Likewise, of the total area, 47.8% is occupied by soils of the Mollisols order; 31.3% by Vertisols; 173.% by Inceptisols; 2.3% by Alfisols; 0.8% by Entisols; 0.5% by Ultisols and less than 0.01% by Histosols.

The soils identified in the Cauca River valley cultivated with sugar cane corresponded to 35 textural families with which 12 textural groups were formed. The textural groups, together with the ustic (dry), udic (humid) and aquic (periodically flooded) humidity regimes and the soil depth generated 33 homogeneous soil groups.

Homogeneous soil groups were defined concisely according to characteristics related to some of the three key factors mentioned above that can give ideas about soil fertility, its limitations and some management strategies to achieve the highest production in each of the groups.