Urban Agriculture And Livestock In The City Of Mexico: An Option For A Sustainable Future
H. Losada, J. Vieyra, J. Cortés, R. Pealing*, H. Martínez, M. López, L. Arias, A.Zamudio, G. Martínez.
Dr. Tito Losada
Animal Production Systems Area
Department of Biology of Reproduction
Division of Biological and Health Sciences
Universidad Autónoma Metropolitana-Iztapalapa
Av. Michoacán y La Purísima. Col. Vicentina. Iztapalapa C.P. 09340, México D.F. 1.
*Researcher from U.K. sponsored by the interchange CONACYT- British Council.
Mexico City is one of the largest urban centres in the world with an estimated population of 22 million living within a surface area of 100,000 hectares. Although the urban development of the city has been carried out following a western model, the long-standing relationship between the city's inhabitants and a cultural tradition of agricultural and animal production based on the use of the new urban spaces and the city's organic wastes has resulted in a technology nearing the concept of sustainability and which introduces the possibility for future self-sufficiency within the large urban concentrations of the capitals of the world.
Research carried out by the Autonomous Metropolitan University at Iztapalapa (UAM-I) has put forward the idea of the existence of three types of space in which agriculture and animal production occur within the city of Mexico. These have been defined as: urban, sub-urban and peri-urban. These spaces are differentiated by the origin of the population involved in agriculture (local or migrant) and the physical relationship between town and country. Characteristics of common interest to all three types of space include the use of recycled materials in construction and in the management of livestock, and the integration of all the family - father, mother and children - in the various farming activities which in some cases are sufficient on which to live, while in other cases complement the family income or provides high quality foods.
The research that has been carried out in the east of Mexico City has revealed the presence of small scale stables which act as small dairy businesses, acquiring adult Holstein cows from the mechanised stables on the outskirts of the city, milking by hand and selling milk and cheeses to the local population. In this type of system a significant proportion of the fodder for the cows (over 70%) is made up of the fruit and vegetable waste generated by the large fruit and vegetable distribution centres of the city. The type of wastes used include maize husks, lettuce, cabbage and cauliflower as well as the foliage from other vegetables such as radish and broccoli. In addition, fruit and other horticultural products deemed unsuitable for human consumption are also made available to supplement animal diets. These include carrots, beetroot, maize and Castillean squash. Our studies have found that 100 tonnes of waste per day is used in complementing the feeding system of approximately 2500 cows, producing an estimated 37,500 litres of milk per day.
Other species of animals that have found a new habitat within Mexico City include pigs and poultry. These are kept within the backyards of family homes. Our research has reported that producers keep an average of 3 pigs and 26 birds per household, but there are some individuals who manage up to 60 pigs, all kept within the family. The type of pigs and poultry reared include native breeds as well as specialised breeds originating from mechanised farming systems - Yorkshire and Hampshire breeds in the case of pigs, Rhode Island and Leghorn in that of poultry. Their nutrition is based on the use of food wastes available from the city including kitchen wastes, stale bread and tortilla, left-over tortilla dough, chicken guts, and fruit and vegetable wastes from the markets, amounting to 4000 tonnes per day.
Some of the pigs and birds are slaughtered in the house in order to prepare various dishes for special family events, but the majority are bought by the city's abatoires, slaughtered and sold to the meat retail trade. Secondary reasons for keeping backyard animals have been found to include, as a source of money in cases of unpredictable economic emergencies, egg production to meet local demand (for use in 'magic', limpias etc.) and in some cases for sport (cock fights).
In the zone south of Mexico City urban growth has been less dramatic which has allowed these spaces to retain their rural character, and consequently act as 'reservoirs' for local tourism. The systems of food production have maintained a form conventional to the rural sector of the rest of the country - with arable production representing the dominant activity, while livestock and forestry are secondary activities with long-standing relationships with arable production.
According to the results obtained from UAM-I's various strands of research, the region incorporates two models of production dating from the prehispanic era and one other brought by the Spanish colonisers - all influenced by the topography of the city. The first of these can be found in the lowland areas and includes the chinampas ('floating gardens') zone where horticultural production - ornamental plants, flowers, maize, beans, squash etc. - predominates, along with other production processes associated with the culture of the area (such as backyard livestock, kitchen gardens and cattle rearing for milk and meat). The second of the aforementioned models is situated in the upland zone dominated by terraces, where temporal crops adapted to the area are produced - maize, oats, cut fodder and of particular interest, nopal.
This same region is also important for its forestry products - firewood, wild mushrooms, resins and timber for the construction of houses and furniture. Other farming systems important in the terraced model of production include natural pastures and cultivated meadows used in the rearing of sheep, for which there is a regional demand (being used in the preparation of barbacoa or steam-cooked meat, stimulated by the increasing importance of tourism in the city). Also included within the upland model are family kitchen gardens and backyard livestock which constitute a form of production associated with the local culture in which the population live alongside the animals that are used for agricultural activities on the terraces. A third, transitional zone is made up of the small valleys that bisect the mountains, in which irrigated agriculture for the production of quality fodder (alfalfa) predominates, along with that of maize.
An analysis of the studied animal and agricultural production systems reveals a close relationship between the different spaces and systems, with the waste products of one system providing a source of energy and nitrogen for another, establishing a good basis for the development of a sustainable alternative for large cities. This interaction is well exemplified by the small-scale milk production of the urban dairies. The organic wastes produced from these stables potentially represent a source of contamination, but are used instead in the production of nopal in the terraced zone in the south of the city - a crop of good productivity with minimal water requirements and able to grow in eroded and/or poor quality soils, and with natural limitations for mechanisation. The excreta from the dairy stables represent a 'connecting agent' which has allowed the producers from both systems to maintain production despite the problems presented by their agricultural medium.
The nopal (Opuntia ficus indica) of Milpa Alta is a plant native to Mexico which was first domesticated by the early populations of Mexico, selected for its production of edible leaves. In fact it is possible to consider this perennial crop to be the most important in the zone, with an area of approximately 6000 hectares and a production in excess of 200,000 tonnes (per year), 75% of which is consumed within Mexico City,and the rest being used in the neighbouring states with a small quantity being exported to the United States and Japan. In all the nopal plantations the use of cattle manure as a source of organic matter and fertiliser is intensive, with a reported use of an average of 600 tonnes of fresh excreta per hectare per year - allowing a weekly harvest of leaves for sale. The producers have indicated that collateral effects of the manure include its properties as a source of water and heat during the dry and cold seasons.
A common issue which has confronted these new forms of agricultural production within the environment of Mexico City is that of the divergence between what the producers do and how the authorities feel agriculture should develop. The differences between the two has created a dichotomy, apparently without solution but rather has brought about a loss in natural materials and resources and incomes which could have been used for the common welfare of everyone.
Interviews with the local authorities carried out by the research team of UAM-I have identified the existence of a series of problems associated with the stables and backyards caused by complaints form neighbouring residents. These complaints relate to the presence of flies and rats which accompany the handling of animal excreta and feed stuffs, the blocking of drains, the excessive use of water and the absence of hygiene employed in the management of the animals and their products (principally milk). If there is any truth to these claims, the evidence suggests that there exist factors which both favour and inhibit their presence, such as the amount of time the neighbourhood has shared the urban space with the animals, and also the external pressures of construction companies looking for land suitable for housing developments.
One possibility that has been put forward on several occasions by Mexico City's authorities to solve the problem of the stables and neighbourhood relations, has been the suggestion of removing the stables from their urban context and relocating them in areas peripheral to the metropolis. Despite heavy investments by Mexico City's government the results to date have been negative, as is demonstrated by the discouragement of dairy activities, sale of animals and in the final instance, the irretrievable loss of an agricultural system. An analysis of the effects of aforementioned suggestion of relocating dairy production has overwhelmingly indicated the creation of new problems for the producers, allied with difficulties in obtaining feed to support production, increasing costs of transporting feed, serious difficulties linked to the market for milk and its derivatives, for young animals and for waste which promote the role of intermediaries. All these factors lower significantly the profitability of these production systems.
According to this situation it is clear that whatever the current government proposal, it must take into account the fact that these urban animal production systems were created under conditions particular to the metropolis, and consequently must be validated as forms of production which correspond to the concept of urban agriculture and be promoted by the authorities within this context. Not to approach the issue in this way is to generate further problems. For example, the suppression of the dairy stables would inevitably effect the producers of nopal and other crops in the south of Mexico City, who faced with an absence of fresh manure would use instead inorganic fertilisers, thereby promoting pollution.