Chinampa Agricultural System, Mexico
- Detailed Information
Sustainable farming has been practised in Mexico since pre-Columbian times by small-scale farmers (owning <25 ha of land), who represent 95% of Mexican farmers; and multi-species culture or husbandry systems (‘polycultures') have been and are a common feature among them (e.g. 60% of corn fields, 80% of bean farming). The Chinampas are polyculture systems on raised beds (‘çamellones') on the swamplands of the spring-fed southern lakes (Xochimilco and Chalco) and the central lake (Texcoco) in the central valley of Mexico -the northern lakes (Zumpango and Xaltocan ) being somewhat saline for agriculture. Chinampas are not Aztec in origin since earlier evidence is found in the ancient city of Teotihuacan, the lowland Yucatan (Maya of Sout-east Mexico), the swamps of Surinam, and in Lake Titicaca (Peru and Bolivia).
The raised beds about 2-4 m wide and 20-40 m long surrounded by canals, 0.5-0.7 m above water level, with sides reinforced by branches and willow trees (‘ahuejotes'), with a thick layer of topsoil on the beds and soil nutrients being provided by topping of fertile organic wastes from the canal and reservoir bottom. Decomposing plants and animals and eroding soil captured by the canals provide organic matter. The canals are used for aquaculture (fish, waterfowl, and newts – axolotl) and to keep out pests and livestock. The surrounding water raises the temperature of the raised beds sufficiently to mitigate frosts. Domestic animals (pigs, chicken, and ducks) are fed wastes from Chinampa crops, and animal wastes are captured by the Chinampa canals. Polycultures on Chinampa beds include corn, beans, squash and chile planted together, or a combination of cassava, corn and papaya. Fruit trees (e.g. Mexican cherry, prickly pear). Cover crops are also planted, as are a wide variety of plants such as green tomato (jitomate), chia, amaranth, chayote, and chilacayote, and edible herbs (uauhzontli, quiltonil, and quelite cenizo). Various grasses and bulrushes grown facilitate basket and mat weaving.
The greatest Aztec innovation was the use of seed germinating beds and seedling nurseries (‘almacigas') at the margins. Chinampas were managed by rituals linked to seasons in the solar calendar, and to Aztec deities for water (Tlaloc) and fertility; and by the high social status accorded to traders (‘pochteca'). Chinampas produce high crop yields such as 8-14 t/ha potato (1-4 t/ha without beds) and 3.5-6.0 t/ha maize (2.6-4.0 t/ha on flat land); and support 15-20 people per hectare per year; and covered 20,000 ha around the two southern lakes under the Aztecs, compared to about 2,300 ha today.
Goods and Services Provided
Chinampas regulate the micro-climate by retaining moisture through capillary action, trap soil and organic matter and promote nutrients cycling between compartments. They provide high yields (40-60%) of terrestrial and aquatic produce by continuous cropping and use of a rich diversity of niches, they provide food and livelihood security that minimize risk and are linked to markets, promote high biomass production by use of a rich diversity of niches, and, therefore, sustainably support high population densities. The Chinampas produce 45% of the ornamental plants for Mexico City.
Threats and Challenges
Chinampas are threatened by the fact that the complex logistics needed for their management are not provided by markets, the eagerness of small-scale farmers to lose their ‘peasant' title with its negative connotations (starving, uneducated, backward people), the desire of farmers to gain status by embracing new technologies and mechanization, the organization of the market for large-scale, capital-intensive monoculture systems, and by the lack of incentives for sustaining them.
Policy and Development Relevance
These systems may be more important for conserving agro-biodiversity and enabling farmers adapt to and cope with climate change uncertainties. They provide a challenge for full ecological-economic valuation in comparison to prevailing policies, institutions and incentives.
Agricultural policies and subsidies have hitherto favoured large-scale intensive monocultures; and their relevance for small-scale polycultures, like Chinampas, needs to be reviewed relative to coping with emerging climate threats and to agro-biodiversity conservation. Chinampas ensure food security and livelihoods to small-scale farmers, thereby alleviating poverty.
Chinampas are of global importance for conserving agro-biodiversity, ensuring food security and livelihoods, and alleviating poverty especially with emerging climate-related threats.