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Savoirs locaux et agriculture durable au Yémen

 | 
Frédéric Pelat
, 
Amin Al-Hakimi

IMPORTANCE OF INDIGENOUS KNOWLEGDE IN AGRICULTURE

Traditional farming systems and their role in developing and sustaining agriculture in the Republic of Yemen

Amin A. S. Al-Hakimi

Texte intégral

1Sustainable agriculture is achieved by using acquired concepts and experiences better to manage natural sources toward a state of constant and sustainable production. Farming systems developed through history to provide man’s basic needs. Through their developmental stages, agrarian systems gained by experiment and experience the knowledge to adapt to their natural circumstances of production and to preserve natural sources while achieving constant and sustainable productivity. Development of farming systems was associated with several different modes of farming and with different plant species adapted to local environmental conditions. The Yemeni farmer could determine and deal with the most important conditions necessary for sustainable agricultural production, through an ideal management of the natural resources, cultivation of various plant species, integration of crop production and animal herds, and management and disposition of rural products. Various studies identify over 150 plant species involved in the different stages of Yemeni agriculture development, and the greater number of species were still being planted at the beginning of the 1970s. Since then many species have started to disappear due to rapid changes in the farming process and progressive loss of traditional farming knowledge and systems. We will discuss in this paper the role of acquired knowledge and traditional farming systems in realizing crop diversity as a main factor for sustainable agriculture in the Republic of Yemen.

Introduction

  • 1 Shaner, W.W., P.F. Philipp P.F, and W.R. Schmehl W.R., 1982, Farming systems research and developm (...)

2A farming system is defined as the significant and constant arrangement of farming activities, the practices of which cope with the physical, biological and socio-economical environment in response to the family’s needs and adjustment to its changing resources.1 Knowledge and practices that did not improve a farming system’s perpetuation disappeared when conditions changed, farming systems developed, and population pressure increased. Nevertheless, in Yemen there are still an indefinite number of farming systems developed by traditional communities that managed well the soil, water, plant cover, and nutrient elements essential and necessary for sustainable farming. Surviving crops diversity is one of the more interesting facets of continuity in farming activity during the last few decades in Yemen. Hence our study focuses on crop diversity as an important factor for sustainable agriculture.

3Crop diversity played a most interesting and essential role for sustaining exploitation and management of such resources in traditional farming systems. Crop diversity conferred several benefits: it decreased damage and loss to blights or diseases that might destroy a single crop, and it decreased the impact of environmental effects such as extremes of temperature and moisture. Furthermore, the diversity of agricultural production permitted the replacement of one crop by another and so promoted and strengthened a continuity of production.

The tradition farming systems in Yemen

4We here mention the most important traditional systems:

  • Farming systems that spread during early periods of agriculture activity, especially from the eastern and southern plains to nearby wādī beds and to regions that receive less than 200 mm of rainfall. This farming activity encompasses crops, e.g. al-kunb, al-tahf, sesame, sorghum, and forage for animal, that can endure relatively arid conditions. In those regions water falling within a natural drainage catchment accumulates to flow onto a small area of land prepared for cultivation. When the productivity of a given field begins to decline, farmers abandon it and move to another fertile plot.
  • Oasis farming, similar to the first system but where water converges naturally to regions of low elevation. Crop diversity in this system is considerable and cultivation of perennial fruit trees and seasonable crops is predominant.
  • Terrace farming, in which constructed terraces protect agricultural soil for growing crops, and make use of water run-off. This system applies essentially to rainfed crops, and crop diversity is considerable as a result of climatic diversity.
  • Wādī farming, in which seasonal floods provide the basic source of water. There is great crop diversity there.
  • Farming in montane plains, where agriculture can draw on direct rainfall as well as ground water and local catchments. The plains generally have deep and fertile soil, and the suite of crops is generally similar across them.
  • Farming based on spate water and ground water. The land is cultivated when there is sufficient flood water, and also draws on ground water. Crop diversity is less than in the other systems because of irregular and seasonal supplies of spate water. This system exists in the hills and plain of Tihāma and in Ma’rib, Shabwa, al-Jawf, and Bayhān. Immediately after a spate al-thaf and millet are sown and the fields produce a harvest a month later ; fields may then be plowed again for planting corn, sesame, black-eyed pea, green pea, melon and pumpkin.
  • Ghayl (spring-water) farming where water flows throughout the year, supporting several types of seasonal crops and perennial fruit trees.
  • Flood farming in areas that can be cultivated once each three to five years depending on the strength and extent of water floods. In such regions, water may be ponded in mud catchments for sustaining one or two crops such as cotton, sorghum, millet, al-thaf, sesame, etc.

5The convergence of several climates (e.g. temperate and tropical) and of multiple farming systems within Yemen have contributed to creating a great diversity of cultivated crops. The ancient farmer could cultivate crops such as wheat, barley, sorghum and vegetables (beans, onions, garlic). There are also many kinds of fruit crops in Yemen, such as Punica granata, Olea chrysophylla, nuts, grapes, date palm, etc., the cultivation of which goes back more than five millennia. Wild forms of many of these plants form part of Yemen’s rich and diverse natural plant cover, the domesticated forms of which include Phoenix dactylifera L. and Ficus carica, and products eaten by Queen of Sheba, e.g. Pistacia vera, Juglans regia, Prunus domesticus and Vitis vinifera.

6The existing thousands of crop species and animal races with unique genetic assets, exploited in the past or in the present, are a result not only of biological and natural evolution over more than 3000 million years but also of farmers’ selection and attention over more than 12 thousand years.

7People around the world differentiate plant species according to their usefulness for food, medicine, and clothing. In Yemen more than 150 species are exploited :

  • As food, such species as Ziziphus sp., Balanites aegyptica… etc., and leaves of al-halqa, al-halass (Cissus sp.), al-dadah (Amaranthus sp.), which were used during times of famine to secure sustenance.
  • As medicine, such species as Cassia sena L., Aloe vera, Anisotes trisulcus F. etc.
  • For commercial and industrial purposes such products as incense, gum, dyes (indigo and dyers’ roots), baskets and mats (al-jarac and al-bahsh).
  • As fragrance, such plants as henna (Lawsonia), al-wars (Flemingia congesta), Arabian jasmine.
  • As spices and in so many other purposes related by folk books and old persons, such plants as al-cinshit, al-rayhān, and al-hulba.

The significance of plant genetic resources to sustainable farming

8Plant genetic resources are kinds and diversity of plant species, whether cultivated or wild, that can be exploited directly or indirectly to produce food, drugs, industrial products, and the like. Diversity is a result of variation in basic genetic species in ways that produced specific genetic characteristics and biological viability. Local plant genetic resources are the basis for creating sustainable farming in response to the wants of producers and consumers within the local conditions of environment and production. Achieving sustainable farming relies on preserving and making use of the remaining plant genetic resources, and on genetic improvements to these resources that produce varieties more conducive to development of sustainable agriculture.

9The local varieties and the wild relatives of farming crops are the endless source of genes that can be scientifically engineered and arranged to produce varieties desirable under local agricultural conditions in order to achieve our ambitions for the future development of our country.

10The earth, including our region, has passed through a lot of climatic variations and disasters over thousands of years. But our predecessors preserved the genetic diversity of farm crops because they considered this the only basis for their lives: these crops contain the genetic diversity to adapt to the environmental conditions in which they grew and evolved. As a result of the continuity of farming and human activity, farmers could select and develop plant forms that responded to their needs and desires, plants adapted to the environmental, social and economic conditions of production and capable of giving high and better quality yields. This led to the appearance of genetic forms that differed from region to region, from village to village, or even from farmer to farmer. Such sources are invaluable because they are a result of experiences and efforts of thousands of years: they are our hidden treasures left to us to preserve, to use wisely, and to pass on to the coming generations.

11Some in advanced countries protest against and object to genetic engineering of crop species and to agro-business farming more generally, because of unacceptable risks to health and environment. Since such crops are not created in traditional ways, a lot of international and regional genetic banks have been established in which to collect plant genetic resources or to preserve these resources in place. The attributes of those resources have been studied and every resource given an identity that can used by researchers and plant growers to produce types useful for sustainable production.

12Research centers, government authorities and universities in Yemen have begun to take an interest in this approach, but the current low capacity does not match hopes for the future. Yemen’s genetic resources are, regrettably, vulnerable to attrition and loss, owing to recent developments in our society. FAO estimates indicate that since the early 20th century, human beings have lost about 75% of the genetic variability of farming crops, and have heavily impacted the natural diversity of plant cover in some areas, especially where plants occupy a narrow ecological niche or are endemic species.

13As plant varieties disappear, so too disappear the genetic composition of these plants. These genotypes would contribute to the creation of plant types suitable to local environments and to different conditions of production; they would also contribute to the creation of plant types suitable to intensified and more stable production. It is impossible to regain these varieties, even if the genetic engineering uses all its available methods.

14Before the early 1970s, farming in the Republic of Yemen had relied on local cultivars with unique genetic attributes, the result of long evolutionary histories. But under the justification of development and in the interest of enhanced food production, farmers and those responsible for managing the farm work have replaced many local cultivars with imported types, thereby replacing a large store of genetic variability with a narrow genetic range often ill-suited to local environmental conditions. So we have to concern ourselves with these types of plants if we are to increase productivity and adjust to climatic and environmental changes. Over the long term this loss of genetic richness threatens the existence of human beings themselves, for as biological variety lessens compensation for lost genetic forms becomes less possible.

Causes of deterioration and loss of genetic resources

15The leading cause of declining genetic diversity is the deleterious effect—whether directly or indirectly, intentional or unintended—of human activities:

  • New varieties produced by international and local research centers and commercial companies are replacing traditional local varieties. The companies that make new varieties compete in the global market by introducing genetically altered strains with enhanced productivity. Farmers in their turn adopt the new strains for their higher yields and enhanced income potential without considering such potential longer-term risks as the failure of new strains to thrive under local conditions. As a result, seed stocks need to be replaced from time to time. Moreover, new seed stocks sometimes introduce blights that may seriously affect other crops. As a result, some improved and imported crops, fruit-trees, forest-trees and new breeds of animals may replace, completely or partially, local varieties and breeds adapted to local environments over thousands of years.
    In the past twenty years, many fruit and forest trees, varieties of wheat, barley and other cereals, and different kinds of vegetables have been introduced to the Republic of Yemen. These new forms have displaced local forms, causing a decline in genetic diversity. This loss is today continuing, as the responsible authorities are generally ignorant of the scientific and practical complexities of this issue. The producers of modern varieties seek a profitable product suitable to as wide a range of environments as possible. Such products require annual replacement of seed stocks, heavy manuring or fertilizing of fields, frequent watering, and aggressive measures against crop pests and diseases. So their unintended consequences include environmental pollution, exhaustion of water resources, and deterioration of soils. New varieties may also introduce new pests that prove extremely difficult to eliminate (e.g. the red palm worm introduced from Pakistan that is destroying at a rapid rate date palms in Gulf countries). In sum, increased productivity and profitability over the short-term is exchanged for long-term degradation of the productive process as a whole.
  • Changing from traditional small-holding agriculture to commercial farming requires systems of monoculture, i.e. a single crop grown over a large area. This new system of production in turn requires the farmer to abandon many kinds of crops traditionally cultivated in a given region, resulting in the loss of local genetic resources. Furthermore, local varieties have a high immunity to local plant diseases whereas the new system leaves the farmer more vulnerable to blights and plant diseases.
  • Without protective intervention, human pressures and environmental exhaustion causes rapid extinction, sharp reduction or displacement of many elements of the wild plant cover and pasturelands. The increased farming load in most regions of Yemen has heavily impacted valuable plant cover.
  • Intense exploitation without conservation measures causes a decline and eventual extinction of many wild plant resources. The multiple uses of Juniperus sp—wood for fuel, foliage for grazing, products from its roots—has resulted in an enormous deterioration of its numbers. Searching for the roots of the hulba plant has led to the destruction of plant cover across huge areas; other examples of species experiencing excessive exploitation include Thymus vulgaris, Cissus rotundifolia, Savadora persica, Dracaene cinnabari, D. serrulata, and the gathering of gum-plants (al-kandar gum) Boswellia sacra, Flemingia congesta, aloes, al-karīra, al-halqa, Indigofera, Cichorium endivios, Breonadia salicina, Adina microcephala, Olea africana, Cordica africana, C.abysinica, and Ehretia cymosa T.
  • Non-indigenous plants, once introduced to Yemen, compete with and often displace local vegetation; examples including the qāt tree, Alhagi maurorum, wild daffodil, and red fig. Some of these new plants also deteriorate the soil.
  • Human disturbances alter the environment promote growth of many kinds of plants such as Balanites aegyptiaca, Acacia mellifera V., and Hyphaene thebaica L.
  • Import of manufactured substitutions for local products made from organic raw materials, e.g. cloth, thread, mats, and baskets, result in neglect of the plants that had been the basis for such industries.
  • Small-holders who maintain some genetic diversity (local crop races) are exposed to increasing pressures of poverty and deprivation, and in response accept new imported species and adopt practices that degrade both land and productivity. One result of this trend is extinction of local crop races. It is very important to work hard to preserve such plants in protected areas, preferably in the same or similar places. Several other social and economic factors induce the extinction of agricultural species, among these factors being the spread of qāt farming, emigration, abandonment of farmsteads, rapid growth of population growth and of food requirements, the search for profitable crops and easy marketing. The environmental conditions of periodic drought, flood events, expansion of desert conditions, exhaustion of ground water resources, and deterioration of soil and terraces simply reinforce this trend.

Effect of technology in agriculture development

16Agricultural development undoubtedly benefits from the valuable contributions of traditional knowledge just as much as it does from new farming methods and techniques. In the optimum combination of traditional and innovative approaches, new techniques are melded with traditional farming systems in ways and at rates that do not damage the natural sources and sustainability of traditional farming. The recent interest in studying farming systems, in order to integrate traditional and innovative concepts, is a response to the need to create sustainable farming.

17Modern techniques for improving agriculture can achieve many advantages for farmers in under-developed countries just as they do for the farmers of developed countries. Provided research takes into account the local farmers’ needs, genetic engineering (e.g.) can facilitate the acquisition of genetic resources that have immunity from blights and diseases and that can endure environmental change.

Conclusion

18The basic force of folk agricultural systems is latent in its functional incorporation of different farming styles, e.g. using land to produce food, hay or fodder, or fuel wood, in a balance that achieves sustainable production rates while also maintaining water, soil, and soil fertility. The ideal use of different biological resources, e.g. raising different kinds of animals and making use of the wide range of available crops, fodder, herbs, trees, fallow plantings, and plant cover to inhibit erosion; encouragement of plant cover to help retain soil moist, maintain congenial temperature and control weeds; construction of houses and villages on land that cannot be farmed ; the system of barrages in valleys to protect farming lands from floods—these are all examples of traditional practices in the management and conservation of agricultural lands that can still instruct us. Such practices preserve farm lands that we inherited from past generations.

Notes

1 Shaner, W.W., P.F. Philipp P.F, and W.R. Schmehl W.R., 1982, Farming systems research and development: guidelines for developing countries, Boulder CO.

Auteur

Faculty of Agriculture, Sana’a University

© Centre français de recherche de la péninsule Arabique, 2003

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