Abstract
The chinampas agriculture is a traditional land use practice in the Valley of Mexico since Pre-Hispanic time. The chinampas soils were constructed by excavation of lake sediments that resulted in the creation of a system of islands separated by channels. The agricultural productivity of these artificial soils was high; also the land use practices included forestry, fish breeding and hunting. Nowadays, the chinampas soils are affected by excessive salinity. We studied 10 representative soil profiles in the chinampas zone of Mexico City in order to characterize their properties and origin, to provide their classification, and to evaluate soil salinization, vertical distribution of the salts and their chemical composition. The soils are characterized by a layered structure, uniform dark grey colour, irregular vertical distribution of organic carbon and clay, and high percentage of carbon. Some soils show an increase in organic matter with depth, and other profiles have maximum organic matter content in the surficial layers and in the subsoil. The dynamics of sedimentation resulted in the decrease in organic matter in the upper layers of lacustrine sediments, because of recent increase in erosion rate and consequent increase in the proportion of mineral particles in the sediments. Most probably high organic matter content in surficial layers of some soils is due to excavation and accumulation of organic-rich subsoil material in the course of digging the channels. The concentration of soluble salts in superficial horizons, expressed as electric conductivity, varies in a wide range from 5 to almost 50 dS·m<sup>-1</sup>. The salts concentrate mainly in the superficial layers of soils. The abundance of the cations of soluble salts is Na<sup>+</sup>&gt;Mg<sup>2+</sup>&gt;Ca<sup>2+</sup>&gt;K<sup>+</sup> and that of the anions is SO<sub>4</sub><sup>2-</sup>&gt;Cl<sup>-</sup>&gt;HCO<sub>3</sub><sup>-</sup>&gt;CO<sub>3</sub><sup>2-</sup>. The alkaline reaction of soils is caused by exchangeable Na rather than by free sodium carbonates. The restoration of chinampas requires a complex approach, combining soil, water and ecosystems remediation.
Highlights
Chinampas are agroecosystems developed in the lacustrine zone of the catchment of Mexico in periodically flooded or shallow areas
Some soils show an increase in organic matter with depth, and other profiles have maximum organic matter content in the surficial layers and in the subsoil
Since distinguishing horizons was difficult and it was not clear whether this discrepancy was a result of pedogenetic processes or lithological discontinuity, we preferred describing the soil by 10-cm layers
Summary
Chinampas are agroecosystems developed in the lacustrine zone of the catchment of Mexico in periodically flooded or shallow areas. These areas were used by small ethnic groups such as chichimeca, acolhua, tepaneca, otomi, some groups influenced by Toltec culture, and, later, dominated by Aztecs. These groups developed a specific culture and technology: irrigation by flooding, and formation of a series of elevated fields for agricultural production (Ezcurra 1990). Chinampas (a word of nahuatl origin: chinamitl – “straw bed”, and pan – “over”) are portions of soil material designed for capturing water. In the course of chinampas use, additional lake mud could be added, or excessive soils could be removed to construct new chinampas (Coe 1964)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
