- The Mongolian experience in combating desertification and its impacts
Presented by : Dr. Tsohiogyn Adyasuren, Director General Environment Science, Monitoring and International Cooperation Department, Ministry for Nature and Environment, Mongolia

- The Chinese experience in combating desertification and its impacts
Presented by : Prof. Zhu Zhenda, Institute of Geography, Institute of Mountain Disaster and Environment and Desert Research, China

- The Benin experience in combating desertification and its impacts
Presented by : H.E. M. René Valéry Mongbe, Ambassador, Permanent Representative of Benin to the United Nations

- The Turkmenistan experience in combating desertification and its impacts
Presented by : Prof. N. Kharin, Deputy Director of Desert Institute, Turkmenistan

- The Chilean experience in combating deesertification and its impact
Presented by : Mr. Samuel Franke Campana, Corporaciòn Nacional Forestal, Chile

- The Brazilian experience in combating desertification and its impacts
Presented by : Mr. Paolo Roberto Franca, Division of Environment, Ministry of Foreign Affairs, Brazil

- The Mexican experience in combating desertification and its impacts
Presented by : Mr. Manuel Anaya, Secretaria de Desarrollo Social, Mexico

THE MONGOLIAN EXPERINECE IN COMBATING DESERTIFICATION AND ITS IMPACTS

Presented by : Dr. Tsohiogyn Adyasuren, Director General Environment
Science, Monitoring and International Cooperation Department, Ministry for Nature and Environment, Mongolia.

SOCIO-ECONOMIC ASPECTS OF DESERTIFICATION IN MONGOLIA

Geography

Mongolia lies in the northern part of Central Asia. It is situated between longitudes 87 44' and 119 50' east and latitudes 41 35' and 52 09' north. Mongolia borders on the north the Russian Federation and on the south, east and west the People's Republic of China. Mongolia is a land- locked country situated at great distances from the world oceans, i.e. 1600 km from the Pacific in the east; 5000 km from the Mediterranean in the west and 3000 km from the Arctic Ocean in the north.

Population

Density of population is a factor changing the environment and finally bringing about desertification. Total population was estimated at 2.18 million in 1991. Annual population growth in Mongolia is one of the highest in Asia with a rate estimated as 2.8 per cent.

Urbanization

Social patterns have also undergone changes, particularly the balance between rural and urban populations. (Settlements are considered towns if the number of residents exceeds 6,000.) The following Table gives data on the balance of population groups (Table 1).

Urban development in arid zones enhances the impact of man on adjacent territories. Areas of desertification are becoming ever greater around urban centers and other settlements.

Table 1 . Number of Urban and Rural Residents of Mongolia (in thousands)

Political Trends

On June 28, 1992, democratic elections were held in accordance with the new Constitution, which was adopted in the beginning of the year, to incorporate the principles of a democratic society based on a market economy. Six political parties participated and 95.6% of eligible voters took part.

For most of the last seven decades, the whole economy, from agriculture to industry, was under the control of central planners and cooperative leaders. These policies resulted in a highly distorted economy, with inefficient use of state assets, slow growth and stagnation. Now the aim of the Government of Mongolia is to transform the economy from a centrally planned to a market one.

Economy

Mongolia's economy is heavily agricultural. Live animals and animal products - meat, butter, wool, hides and furs - account for half of Mongolia's output and almost 90% of its exports. Principle imports include machinery, petroleum, textiles and building materials.

Agricultural Production

Mongolia is a country of ancient cattle rearing. This branch of the economy has the greatest impact on the environment and is one of the main causes of desertification. Table 2 below shows livestock growth from 1918 to 1990.

Table 2 : Number of Livestock (in thousands)

The years of central planning greatly stimulated the dependence of livestock numbers in the arid zone on climatic factors, e.g. recurrence of droughts and periods of hot winds. Years with above average rainfall seasons would see a drastic increment in the total number of livestock, while drought years in turn brought heavy losses of cattle. Nomadic grazing parties remained the sole means of feed procurement in dry years due to the absence of fodder production. Migration in search of feed to relatively benign regions increased the density of grazing cattle and spurred degradation of rangelands. Most productive rangelands were subjected to the heaviest anthropogenic impacts in dry years.

NATURAL FACTORS IN DESERTIFICATION

Precipitation

Precipitation is generally low, ranging from less than 50 mm per year in the extreme south (Govi Desert area) to just over 400 mm per year in areas of the North. 86 to 96 per cent of precipitation occurs in the warm season, which continues from April until October, with 66 to 78 per cent in July and August alone.

The average countrywide precipitation of 230 mm per annum translates into an average of 31.1 cubic kilometers of rainwater. Of this amount, roughly 90 per cent returns to the atmosphere through evapotranspiration at an extremely high rate compared to other regions of the world. Of the remaining 10 per cent, 63 per cent becomes surface runoff. Most of the surface flow component (95 per cent) flows out of country, while a small portion flows into lakes and basins within the country. About 36 per cent infiltrates into the soil and contributes to subsurface flow. Thus, of the total annual precipitation, only about 3 per cent infiltrates into the soil to replenish aquifers or becomes potentially available as a water resource in the form of soil moisture and ground water.

Precipitation in the whole territory of Mongolia averaged below normal from about 1944 to 1950 and above normal from 1950 to 1968.

As mentioned above, annual precipitation in the Govi Desert area is less than 50-100 mm. In some areas of the Govi, there was no precipitation for as long as 20 years. During the 1960- 1970s, there was an observed tendency of decreasing precipitation. This likely shows that the territory of Mongolia is located in the arid zones of the world where there is less precipitation. The Mongolian Govi or Central Asian Govi Desert area is one of the most arid lands in the world. In the last 20 years, precipitation dropped by 20 per cent in that area. (Figure 3). This tendency of decreasing precipitation depends on many causes, but mainly on global climate change, especially on global warming.

Temperature

The average temperature in Southeast Mongolia is +2oC to +4oC while that in Northwest Mongolia is -7oC to -5oC. The absolute minimum temperature is -45oC to - 53oC in January, and the absolute maximum +40oC to +45oC. Due to isolation from the world oceans and their moderating influences on temperatures, fluctuations in temperature are extreme, both annually and diurnally. Fluctuations can be as high as 30oC in a single day. The difference between average winter low and summer high temperatures is in excess of 50oC, as compared to a 25oC range in Eastern Europe. The annual mean air temperature increased by 0.6 to 0.8oC during the period 1940-1990. Because of increasing air temperatures, there is much more risk of ariditization, epecially in the Govi Desert area. Because of low precipitation and intensive warming in Mongolia, there is an increasing chance of dust and sand storms.

Dust and Sand Storms

Most soil degradation is caused by human activities, such as overgrazing, and overexploitation, and by the frequency of sand and dust storms. Sand and dust storms are frequent in the Govi Desert region, particularly in the Great Lakes hollow (71 to 125 times per year), in the southeast Govi Altai Mountain Range (70 to 98) and around the Arts Bogd Mountains (80 times per year) (Figure 5). Generally, in Central Asia, the number of days with dust storms is high. The number of days with dust and sand storms is increasing decade by decade. This tendency is a good indicator of desertification processes.

STATE OF DROUGHT AND LAND DEGRADATION IN MONGOLIA

Drought

Drought with a frequency of 30 per cent and more covers much of Mongolian territory in the summer season. The drought index calculated for all months in the period 1940-1992 has been estimated for affected areas on the basis of averaged values. The drought index (Si) proceeding from this calculation uses the following criteria:

weak drought 1< Si< 2

moderate drought 2< Si< 3

severe drought Si> 3

normals -1< Si< 1

wet -1> Si> -3

The frequency of drought in Southern Mongolia and in the Govi Desert region increases year by year. Research on the drought problem also demonstrates that in Mongolia, Northern China and the whole of Central Asia, there is a tendency towards increases in Si in both spring and summer seasons; in other words, there is more risk of drought in the same period.

Using AVHRR information received from NOAA in 1982-1987, we determined drought conditions in Central Asia as reflected in table 3.

Table 3: Distribution of dry and drought areas in Mongolia determined by NDVI value (%)

Land Use

The territory of Mongolia is 156,411.4 thousand hectares. About 80 per cent of Mongolian territory is farm land. The main economic sector is animal husbandry. Since Mongolian cattle use four season pastures, 97% of farm land is used for rangeland. Because of the country's economic development and urbanization, the area for settlements has increased from 74.9 to 452.0 thousand hectares. Farm-land per capita was 152 ha in 1960 but decreased by 1990 to 60 ha. Since 1990, new protected areas were created such as Han Hentii, East Mongolia, and Uvs Lake.

LAND DEGRADATION IN ARID ZONES

About 41.3 per cent (19.5 per cent in the Govi and 21.8 per cent in the Desert area) of Mongolia is affected by desertification.

Degraded Rangelands

Moving from North to South, pasture yield is decreasing. As compared with the forested steppe, the yield of the Govi arid area is 3.18 times less. There is a tendency towards desertification in part of the degraded rangeland of Mongolia. 76 per cent of Govi arid desert area shows slight desertification, 20 per cent moderate, 3 per cent severe and 1 per cent very severe. Land which is near-by rural settlements and big cities occupies 15-16 million hectares, and in those areas land is also overgrazed and soil is degrading.

Table 4 : Extent of desertification in Mongolia (%)

Table 5 : Area occupied by sand (thousand ha)

As of 1990, the sand desert area has increased by 38.000 hectares since 1941. An estimated 60 wells and 160 cattle barns have been buried by moving dunes since 1942. This means that the process of covering the Govi pasture by sand is accelerating. The basins of rivers such as the Baidrag, the Tui Taats and the Ongi which flow from the north to the south, have decreased by 25-33 per cent, and more than 80 small rivers and springs (tributaries) have disappeared. This was the reason for the drying up of 5 lakes in the Govi desert area.

Table 6 : Number of depleted tributaries or rivers (A) and depletion of lakes (B)

The decrease of water resources in arid areas of Mongolia negatively affected the vegetation cover. Vegetation cover productivity has fallen, the cover itself has diminished and the number of plant species has fallen. Totally, more than 1 million hectares of pasture land has been degraded, and pasture yield in 1990 was 1.8 - 2 times lower than in 1960.

Degraded Cultivated Land

The total area of cultivated land in Mongolia has reached 1.36 million hectares. Table 7 shows the results of research done in 1991 on 1204.4 thousand hectares, or 90 per cent of the crop land area.

Table 7 : Degradation of cultivated land (%)

Crop land area is degrading and has lost productivity. The organic matter (humus) of the degraded crop land has decreased by 29.3-48.7 per cent. On the whole, soils in Mongolia are generally dark chestnut and chestnut, typically fine light and silty, around 20-30 cm deep with an organic matter content of 2.5-3.5 per cent and a pH of 6.0-7.0. During the last 30 years of use, 889 tons of soil was lost for every ha of moderately degraded cultivated land, and 1299 tons for every ha of severely degraded cultivated land. More than 90 per cent of crop land has been eroded by wind and water, with about 970 thousand hectares losing its organic matter by wind erosion. During this period the soil layer with organic matter in cultivated lands thinned by 7-8 cm. 110 thousand hectares of cultivated land thus were lost to crop land rotation.

The other reasons for land degradation are land use in industrial and other sectors, such as geology, mining, transportation and military, and lack of recultivation.

Deforestation

About 10 per cent of the land surface of Mongolia, equivalent to some 15.2 million hectares, is covered by various types of forest. Larch (73.6 per cent), cedar (13 per cent), pine (8 per cent) birch (5 per cent) and other species (fir, aspen, etc.) dominate the northern part of the country. Haloxylon ammodendron forests in the Govi account for 28 per cent of the forest cover. Total volume of wood is 1.2 billion cubic metres.

About 10,000 to 14,000 hectares of forests are cut annually for timber, whereas only 5,000 hectares are reforested, and another 5000 to 6000 hectares are left for natural regrowth. This results in a net loss of forest resources, further decreased by frequent forest fires and other calamities, such as insects. The total annual loss to insects is of the same order as the total lost commercially by logging.

CAUSES OF DESERTIFICATION

The natural causes of desertification include a limited humid period, low precipitation rates, great wind velocities, dust storms, extended dry and hot weather spells, depletion of ground water, higher concentration of salts; and sledging of the soil surface. Other causes are reduction in the productivity of rangelands; changes in vegetation composition and wildlife due to over-grazing; felling of Haloxylon and gallery forests, elms and poplars; road construction; eolian erosion; depletion of natural vegetation and soil cover; industrial impact on the lithogenic foundation; changes in the chemical background balance of the land; depletion of natural soil and vegetation cover; and extermination of wildlife.

Specific human activities that have led to serious and widespread desertification in Mongolia are explained below:

First, crop cultivation is an important reason for desertification, particularly soil erosion, because spring tilling coincides with the season of intensive wind. Most of the cultivated areas are devoid of trees or other wind breaks. In the Govi region, the average wind speed is 3-4 metres per second or even more, which can cause significant soil moisture loss and erosion. It is estimated that over the past 30 years, about 35,250 tons of soil have been lost for each hectare of cultivated land due to wind erosion alone. Half of all cultivated land in Mongolia is considered to be degraded to some degree. New land brought under cultivation is mostly fodder or pasture land, and a significant percentage of this is marginal and environmentally unsuitable for crop production.

Animal husbandry, especially in the arid and semi-arid regions, is an important cause of soil erosion. In all regions, grazing pressure is greater near settlements. The carrying capacity of pasture land is frequently exceeded in the areas receiving greater grazing pressure, resulting in an inferior composition of plant species and soil denudation. It is estimated that a total of 3.6 million ha. of denuded land has appeared in 62 somons (districts).

It is also estimated that nationwide there are four times as many vehicle tracks than are necessary. They have denuded and degraded about 0.7 million ha. of land. Mining and inadequate waste management are other serious factors in land degradation. An estimated 110,000 ha. have been degraded by coal and other mining. The development of strip mines, and the deposition of spoils and tailings degrade land resources. Only a minimal amount of land degraded by mining activities has been restored.

From 1941 to 1990, the desert area in Mongolia increased by 38000 ha. In addition, an estimated 160.000 ha. have undergone some degree of desertification, exhibiting loss of vegetation, an increase in sand cover and development of sand dunes.

RESPONSES

In view of the wide range of factors contributing to the desertification problem, a multifaceted approach to reversing land resource degradation trends is needed, including in depth land use planning, infrastructure development and reforestation.

Implementation of the National Plan of Action to Combat Desertification is important but, given the present situation of the country's economy, it is impossible for the Government of Mongolia to implement the Plan. Active participation of donor countries and international organizations is needed. Such support could include the following:

i. building national capacity;

ii. providing necessary equipment;

iii. marshalling financial support for combating desertification and for reforestation; and

iv. implementating an integrated program of ecosystem rehabilitation in the Govi and rangeland areas.

REFERENCES

National report of Mongolia for UNCED, 1991

ESCAP, UNEP, National Plan of Action to Combat Desertification in Mongolia, 1992.

SCNE Mongolia, Proceedings of the Symposium on Global Change and Govi Desert, Ulaanbaatar, 1991.

The First PRC-Mongolia Workshop on Climate Change in Arid and Semi-Arid

Region over the Central Asia, Beijing, 1993.

THE CHINESE EXPERIENCE IN COMBATING DESERTIFICATION AND ITS IMPACTS

Presented by : Prof. Zhu Zhenda, Institute of Geography, Institute of Mountain Disaster and Environment and Desert Research, China

Desertification is an important environmental problem in the world today. In China's situation, desertification is land degradation. It means the process by which desert-like conditions appear in former nondesert regions as a result of the destruction of the ecological equilibrium of fragile ecosystem by intensive human activities. This process causes decline of biomass productivity and reduction of arable land resources.

Desertification in China can be divided into two types: The first is desertification caused by wind action, that is wind erosion and wind deposition. It mainly occurs in Northern China and Northwestern China in landscapes characteristed by rough land surface, wind-eroded land and shifting sand dunes on the land surface. The second type of desertification is caused by water erosion. It can be found in two regions, Southeastern and Southern China's hilly region, where granite, red bed and laterite constitute the majority of surface material, and the region of dry hot valleys and limestone mountains in Southwestern China.

Desertification consistently occurs in fragile ecological environments where undue human activities destroy vegetation to a breaking point beyond which land degradation and desertification are accelerated by wind erosion in North China or water erosion in South China.

According to preliminary estimates, the total desertified area in China is 776,000 km2 or 8.08% of total land area. Desertified land caused by wind erosion occupies 344,000 km2 and desertified land caused by water erosion accounts for about 367,000 km2. There are also 65,000 km2 affected by salinization. Moreover, these desertified lands are all expanding continuously under the influence of human activities.

The expanding processes of desertification are most noticeable in the transitional zone between the farming and the grazing areas in Northern China and in the laterite and granite hill region in the Southern China. For example, the area of desertified land of the Bashang grasslands in the north part of Hebei Province has expanded from 13.4% in 1975 to 24.9% in 1987, and the area of desertified land in the grazing grasslands in the eastern part of Inner Mongolia has expanded from 18.1% in 1975 to 30.4% in 1987 (Table 1).

Table 1 : The development of desertified lands in Northern China.

Table 2 : Different causes of desertification in Northern China

Table 3 : Nature of the occurrence of desertification in Northern China

Desertified land caused by water erosion in the granite and laterite regions of Jiangxi Province has expanded from 12.9% in 1970 to 26.7% in 1980. In Guizhou Province, it is increasing at a mean rate of 9.1 km2 per year. The rocky and semi-rocky desertified land in the Wujiang River Basin reached 7,440 km2 in 1980, accounting for 8.5% of the total basin's area. Desertified land formed by water erosion in the dry hot valley of Yuanmou County in Yunnan Province makes up 40% of the total area of the county.

The landscape of desertification in arid and semi-arid regions can be divided into three types:

i. shifting sand dunes;

ii. wind-eroded land and rough surfaces; and

iii. reactivation of fixed sand dunes.

In sub-humid and humid regions, the main landscape is "badlands", which are formed by water erosion on weathering crusts of various rocks (granite, red beds, laterite). It resulted from slope cultivation, under which water acted on the loose weathered granite or red bed formations, caused sheet erosion, gully erosion and collapse (by both water and gravity action) and formed "badlands", i.e. dissected, inclined and deteriorated land. In the limestone region, after vegetation was destroyed or after 4-5 years of cultivation, the sloped land would lose its production capacity due to severe topsoil washout, forming rocky desertification. In the hot dry valley of Southwestern China, mud-rock-flows formed into rock and gravel mulching layers on the valley plain, especially at the mouth of debris flow gullies. Such gravel belts formed along the river in a cone, producing a gravel desertification landscape.

Since land desertification is an important degradation under fragile ecological conditions, why did it occur in the hilly and mountainous region of the humid zone with favourable water and heat conditions? This is because of the contradiction between environment resource and population pressure (population density 150 person/km2 - 250 person/km2) in these regions which led to the reclamation of mountain and hill slope) with thin soil layers. Intensive and concentrated rainfall accelerated soil loss, resulting in land resource loss, land productivity reduction and land desertification in the humid zone.

The dynamic process of land desertification in China is illustrated in Figure 1.

As a problem of land degradation, desertification control requires complex engineering that can be done only after systematic research and overall planning. First, we must improve ecological systems in arid, semi-arid, dry subhumid, and humid regions and take measures in line with local conditions to control desertification in these regions. The control of desertified land should be focused on two objectives: ecological benefits and economic results. Ecological principles of appropriate utilization should be realized. The utilization and development of desertified land areas should consist of protection and rehabilitation. In order to create better social, ecological and economic conditions, it must make rational use of land and energy, effectively control population growth in order to reduce population pressure on the land, reduce damage to vegetation, and rejuvenate the land in which desertification has taken place.

Since the founding of the People's Republic of China, the Chinese government has paid considerable attention to research on desertification control. About 12% of desertified land has been checked from expanding and 10% has been reclaimed.

Since the UN Desertification Conference in 1977, China has shifted its efforts to establishing experimental research in different types of desertified land. At the same time, it continues basic research on desertification, which has become a new branch of ecological science. Through the joint efforts of local governments, local people and scientists, many experiment sites have made remarkable process. They have succeeded in popularizing these experiments in desertification control and have won awards from governments. China has been entrusted by UNEP and ESCAP with running international seminara, training courses and symposia eleven times. China has also sent a scientific group to Mali for a cooperative study on the feasibility of Green Belt Programme.

Measures of desertification control are illustrated in Figure 2.

This model tallies with the actual situation of different desertified lands and achieves the goal of unifying ecological, economic and social benefits. The following are some successful examples:

i. Arid Zone: In the Pinchuan area of Linze County in the sandy desert, measures adopted such as establishing sandbreak forests on the fringes of oases, afforesting farmland, building shelterbelts inside the oases, planting pathy forests in interdune flat outside the oasis, erecting sand barriers on the dune surface and transplanting shrubs inside the sand barriers, have halted the spread of desertification while some abandoned lands have regained productivity and formed into new oases. In the case study region, shifting sand area has decreased from 54.6% before rehabilitation to 9.4% after, while the oasis area has increased from 8.3% to 37.8%.

ii. Arid Zone: Shapotou is an example of combatting the encroachment of shifting dunes. Along the railway, by establishment of checkerboard protection with straw and the plantation of shrubs inside the checker board, vegetation cover increased about 20-40% from 5% in the past. Sand dune hazards are under control and the railway is safely protected to pass through the Tengger Desert. For the shifting dunes on the lower terrace, as flood water is pumped, dunes are flattened, sandy soil is reclaimed and protective shelterbeds are planted, thus sandy land was turned into an artificial oasis and orchard.

iii. Semi-Arid Zone: in th rehabilitation of the shifting dune area of the Raobu meadow land in Naiman, the coverage of grass and forest increased from 10% before rehabilitation to 30% after rehabilitation, and grain output grew by 60%.

iv. Semi-Arid Zone: In the Yulin area, at the southern edge of the Muus sandy land, local people have controlled over 333,000 hectares of shifting dunes and planted trees to shield 100,000 hectares of farmland against the shifting sand. Today, 34.5% of the area's land is covered with trees and shrubs. Approximately 3,500 hectares of desertified land have been reclaimed, and average per capita grain output in the area has reached 400 kg. About 5,000 poor families have become rich by planting trees and grass and raising livestock.

v. Sub-Humid Zone: Along the ancient river course in Yucheng County, following three years of rehabilitation measures, such as levelling sandy land, establishing farmland shelterbelts and setting up water conservancy project, 79% of blown sand land has been transformed into farmland.

vi. Humid Zone: Rehabilitation of desertified land caused by water erosion in the Tangbeihe River Valley of Zingguo County, an area of severely desertified land, reached 82.4% of the whole basin. After 10 years of rehabilitation, vegetation cover has increased from 10% to 35%. Total grain yield grew by 32% and average personal income increased 7 times.

The above examples demonstrate that once measures have been adopted, land desertification in fragile ecological zones can be reversed. Land productivity can be restored and ecological environment can be improved, thus achieving better ecological, economic and social benefits. China will continue its efforts in the struggle against desertification to benefit not only its own people but also people all over the world.

THE BENIN EXPERINECE IN COMBATING DESERTIFICATION AND ITS IMPACTS

Presented by : H.E. M. René Valéry Mongbe, Ambassador, Permanent Representative of Benin to the United Nations

ANALYSIS OF DROUGHT AND DESERTIFICATION IN BENIN

Situated in West Africa, between latitudes 6o15' and 12o30'N and longitudes 1o and 3o40'E, the Republic of Benin covers an area of 112,600 km2 with a population of approximately 5 million. It is bordered on the north by the Republic of Niger and Burkina Faso, on the west by Togo, on the east by Nigeria and on the south by the Atlantic Ocean.

Typical Guinean Subequatorial to the south, the climate becomes Soudanian in the north and even Soudano-Sahelian in the extreme north-east on the frontier with Niger. Like most countries South of the Sahara, Benin has experienced several decades of climatic variation in the form of strong rainfall irregularity, which culminated in the droughts of years such as 1958, 1977, and 1983.

These climatic anomalies, together with poor exploitation and, in some cases, overexploitation of natural resources exposed the existence of a particularly fragile ecological zone. The process of degradation, commonly known as desertification, occurs notably in the northern part of the country.

MANIFESTATIONS AND CONSEQUENCES OF DROUGHT AND DESERTIFICATION

The manifestations and consequences of drought and desertification are numerous but it is most important to analyze the physical, human and socio-economic dimensions.

Physical

The dry harmattan wind, initially experienced in the central and northern parts of the country, progressed recently to the southern part with both strength and unusual duration. Sand winds, unknown in the past, also made their appearance in the central and northern zones in recent years.

From a hydrological viewpoint, drought has seriously altered water courses, lakes and lagoons to the point of drying them up. A general decline of water tables has also rendered many wells useless.

From a biogeographic viewpoint, one observes a modification of vegetation cover with the appearance of xerophile plants in forest zones. In addition, animal populations are threatened by pools and points of water drying up.

The regression of vegetation cover exposed soils to erosion, with considerable losses in arable lands and a general decline in their productivity. Measurements on eroded parcels by the National Center of Agricultural Studies during the 1983 growing season showed, on bare ground, a topsoil loss of close to 18 tons per hectare and a loss of moisture close to 23 cubic meters per hectare. The same studies showed losses in parcels with good soil cover of 1 ton per hectare of topsoil and of 3 cubic meters of moisture.

Human

Agricultural production systems (modes of appropriating and dividing land, cultivation techniques and the like) are contributing more and more to the extension of zones vulnerable to erosion. In addition, wood cutting, land reclamation, annual bush fires and overgrazing are some of the causes of deforestation observed throughout the country along roads and railroad right of ways. Such activities cause year after year a progressive disappearance of some local fuels and a considerable regression of some types of woody biomass. According to an FAO study carried out in 1978 by the project "Continuous Observation of Tropical Forest Cover" , forest cover that once occupied 11 percent of Benin now accounts for only 0.55 percent of national territory.

As a consequence of these trends, migration from rural areas has reached worrisome proportions. Migratory movements of people and animals in search of fertile land, water points and pasture have produced serious imbalances in zones which had been ecologically stable. Furthermore, transhumant pastoralists of the northern regions of the country, and those of neighboring states, periodically invade the central, and increasingly the southern, parts of Benin.

Socio-Economic

There has been an alarming general decline in production of both crops and animal products. The cereal shortage was estimated in 1983 at 50,000 tons. The loss of pasture and drying up of water points entailed longer and longer transhumance routes with considerable losses in animal weight, forcing herders to sell their animals at very low prices. Production from marine and fresh water resources also declined throughout the country during recent decades by 50 percent from 48,000 tons in 1960 to 24,000 in 1981.

This general drop in production affected other economic sectors. For example, manufacturing slowed for lack of raw materials such as palm and peanut oil. It also led to massive imports of consumption goods and foodstuffs, capital flight, deterioration of the balance of payments and increasing pressure on the budget of both the government and households.

In the great cities, the reemergence after some years of begging testified eloquently to the deterioration of living conditions. To better understand the phenomena of drought and desertification, which has serious consequences, it is necessary to analyze government policies to combat desertification and mitigate drought.

LESSONS LEARNED FROM THE NATIONAL PLAN TO COMBAT DESERTIFICATION AND MITIGATE DROUGHT

Despite the extreme gravity of the phenomena descried above, various socio-economic development plans implemented until now did not emphasize measures against drought and desertification. Although some urgent actions were taken, they lacked consistent follup because they were not integrated in a global development strategy with the participation of local populations.

Considering the significance of drought and desertification, and their implications for the socio-economic development of the country, it is imperative to develop a coherent action plan, as well as adequate means of implementation and followup. This should be done in the framework of chapter 12 of Agenda 21 adopted by the UNCED Conference and the future application of the international convention on combatting desertification now being elaborated.

A NEW STRATEGY TO PROMOTE SUSTAINABLE DEVELOPMENT WHILE COMBATTING DESERTIFICATION AND MITIGATING DROUGHT

To deal with the current situation in Benin resulting from the ominous consequences of desertification described in this document, it is imperative to revitalize the Plan of Action for combatting desertification and mitigating drought adopted in 1985. This Plan of Action is not, will not be and does not have to be considered simply as a campaign to combat desertification and mitigate drought but should be considered as an essential element of the general development process and a means to eliminate poverty.

More generally, the basic objective of this Plan of Action will be to increase, respecting ecological limits, the productivity of land so as to improve the quality of life and habitat of the population by insuring it energy security, sustainable economic growth and productive employment, along with the security and stability of flows of financial resources for development. Clearly, without integrated implementation of envisaged activities, no program or plan to combat desertification and mitigate drought can give satisfactory results.

In the framework of the new strategy and thanks to the financial and technical support of our partners in development, particularly the World Bank, UNDP, GEF and UNSO, Benin implemented in 1992 and 1993 two projects namely:

i. The Management of Natural Resources Project whose components were: strengthening of the Forest and Natural Resources Directorate (elaboration of a new forest code and a forestry policy document prioritizing important actions), natural forest management, management of catchment basins, study of land-tenure regimes, management of wildlife, including measures against poaching, and training; and

ii. A project for the participatory management of natural forests and rural reforestation for the creation of carbon sinks, situated in the Soudano-Sahelian part of Benin and financed by the GEF with the technical support of the UN.

CONCLUSION

The different factors causing drought and desertification being more or less well-known, these actions could not be, and are not, considered by Benin as measures in a simple campaign to struggle against the scourges of drought and desertification. The implementation of these actions, which has already begun within the modest means of the population and the government of Benin, is perceived as being of essential importance by the authorities of Benin.

THE TURKMENISTAN EXPERINECE IN COMBATING DESERTIFICATION AND ITS IMPACTS

Presented by : Prof. N. Kharin, Deputy Director, Desert Institute, Turkmenistan

The Desert Institute of Turkmenistan has carried out an inventory of Central Asia's desertified lands, developed criteria of desertification assessment, and prepared a desertification map (scale 1:2 500 000). Almost all of Central Asia belongs to the Aral Sea basin, whose area is about 2 million square km. The Aral Basin has become an ecological disaster area. In 1960 the Aral sea encompassed 64,100 sq.km., in 1991, 34,400.

The area of the Aral Sea has contracted like a shagreen skin, giving way to saline land. Irrigated land is salinized because of incorrect land cultivation methods. Monoculture cotton prevails in oases. Ground water is polluted with pesticides, herbicides and defoliants. Toxicity of ground water is 5-10 times the minimum acceptable level. And still people drink this water!

The new independent states of Central Asia (Kazakhstan, Uzbekistan and Turkmenistan) have inherited this problem from the former USSR. It is impossible to solve it in a short span of time, however, here is just one example of solutions pertinent to Turkmenistan. The government has issued a decree on the free supply to the population of gas, electric energy and water; a plant has been built in Ashkhabad, which produces clean drinking water. The positive effect on desertification was already felt in the first year. The rural population ceased to cut the saksaul tree (Haloxylon) when in the last 100 years the area where saksaul was grown diminished by half.

We have developed the concept of an Arid Land Centre for monitoring desertification, including a data bank based on space monitoring. This Centre was established two years ago in Ashkhabad. We have also offered to the Government of Mali and the Ministry of Forests of Iran, as well as to UNEP and ESCAP, our proposals to establish another centre. The creation of a network of such centres would promote the development of a single standardised monitoring network. Finally, we have developed a methodology on assessment and mapping of desertification.

THE CHILEAN EXPERIENCE IN COMBATING DESERTIFICATION AND ITS IMPACTS

Presented by : Mr. Samuel Franke Campana, Corporaciòn Nacional Forestal, Chile

INTRODUCTION

The surface affected by desertification in Chile corresponds to 33 million hectares or approximately 50% of Chile's continental territory. The physical, chemical and biological impacts of desertification processes not only cause deforestation, loss of fertility, sedimentation of river basins and low crop yields but also have socio-economic impacts which generate poverty and rural migration. The population lives under the permanent menace of environmental degradation of its means of subsistence in a classic vicious circle where poverty, over-utilization of resources, and environmental degradation lead to more poverty.

In Chile, around 1.5 million persons in dryland areas are directly affected by desertification problems. This represents 13% of the non-urban population.

ENVIRONMENTAL SITUATION

The Social and Geographic Situation of Chile

Chile is located between parallels 19 and 55, occupying a long (4200 km) and narrow (200 km) stretch of land with a surface of 756.65 km2 and a population of 13 million people. Chile borders Peru in the North, Argentina and Bolivia in the East, the Pacific Ocean in the West and the Chilean Antarctic Ocean in the South. One half of Chilean territory consists of arid and semi-arid zones where human activity relies mainly on irregular rainfall. Climatic variations depend partly on the periodic El Nino phenomenon in the North and on the permanent influence of the cold Humbolt current on the coast in the North and the Center.

Eighty-six percent of the urban population, representing fourteen percent of the labor force, is concentrated in large cities. This urban-rural population imbalance is also refleced in per capita income patterns. The poorest agricultural communities have a per capita income around $200, twelve times less the $2400 national average. The Chilean population is around 95% mixed Indigenous-Spanish, 4% European origin, and 1% pure indigenous. The predominant religion is catholicism. National behaviour is rooted both in Spanish culture and modern processes of foreign transculturation.

Climate

On the basis of the Koppen classification, in Chile, we find the following climate types:

i. Sub-tropical arid climate (B), between latitudes 19 and 33 south, characterized by aridity and absence of forests;

ii. Warm temperate climate with sufficient humidity (Cfa,Csb) between latitudes 33 and 39 south, characterized by clear summers and humid winters towards the south;

iii. Rainy temperate climate (Ct) between latitudes 39 and 55 south, characterized by high precipitations and redued temperatures;

iv. Cold grassland climate (Bsk) between latitudes 53 and 55 south in the province of Magallanes, characterized by low temperatures and precipitation;

v. Ice and polar climate (EF) in the high parts of the Andes mountain range along all of Chilean territory; and

vi. Tundra climate (ET) in limited areas of the extreme south, characterized by very low temperatures, high precipitation and frequent snow.

The climatic regions affected by desertification are arid, warm temperate, and cold drylands. Climate data showing different combinations of temperature and humidity (LPC) indicate that hyper arid, arid and semi-arid zones represent 66% of the total surface of the country (see table 1).

Table 1 : Relation between Climatic Zones and LPC

Vegetation

Climate is the determinant factor in the distribution of vegetation with regard to both latitude and altitude.

In the arid or xeromorphic zone of the north, the Atacama desert extends for approximately 1000 km. It is one of the most arid regions of the world. Rainfall has not totalled more than 0.1 mm ,and the desert has not flourished, for 30 years. Lack of vegetation and the presence of wind favor severe and intense processes of wind erosion.

In the center north of the country, which stretches for approximately 5000 km., we find xerophitic formations of cactus and shrubs, the later due principally to over-exploitation of land, overgrazing and mining activities. This zone is highly vulnerable to processes of wind and water erosion, and to intense processes of desertification.

Towards the center of the country, we find the transitional semi-arid and sub-humid zone, a mediterranean mesomorphic phytogeographic zone. To the north of this zone, shrubs and steppe formations of the sclerophitic forest dominate with temperate forest to the south. Strong demographic pressure, continued utilization of soils for cereal production, deforestation and forest fires are the main causes of desertification.

Towards the south of the country, the hydromorphic phytogeographic zone consists of different types of forest, both deciduous and evergreen. These Chilean native forests, as well as natural rangelands in the zone, are subject to water erosion and in the extreme south of the country to wind erosion. Factors such as overgrazing, irrational utilization of natural forests and forest fires have been the main determinants of desertification processes there.

Physiography

The Andean and coastal mountain ranges are both products of major tectonic actions leaving large valleys and flat lands and allowing urban and agricultural development. The Andean range registers a high number of active and inactive volcanos. Occasional eruptions of active volcanos determine the morphology of soils in the central south of the country. Between the Andes and the Pacific Ocean, we find the parallel coastal mountain range. The geomorphological characteristics of Chilean territory include a large difference in altitude between the Andean Cordillera range with an average altitude of 4000 m and the coastal range at sea level.

Soils

Distribution of Soils

The FAO classification of soils used in the Soils Map of the World is reflected in Table 2, and Figure 1 ( Distribution Map of major soils groups) on the basis of the major soil taxonomic units expressed in per cent of national territory.

Table 2 : Soil Classification (based on FAO system)

Potential Use of Soils

Soil distribution on the basis of potential use is reflected in Table 3, which covers 75.7 million hectares of the country (excluding the Chilean Antarctic Territory).

Table 3 : Potential/Actual Soil Use in Chile

Unproductive lands

On the basis of potential soil use, arable lands are limited in area. Rangelands represents 10.7 per cent, and forest lands 44.6 per cent, of Chile while a large area of 37.5% is unproductive.

PRELIMINARY DIAGNOSIS OF DESERTIFICATION IN CHILE

Causes and Magnitude of Desertification Processes

Preliminary estimates indicate that more than 50% of Chilean territory is affected by desertification. The predominant causes are: deforestation, overgrazing, over utilization of land for agriculture, forest fires and use of land without regard to its classification and qualities. The distribution of the 33 million hectares affected by desertification processes is as follows:

Figure 2 : Preliminary map of Desertification Processes in Continental Chile.

Erosion and Loss of Natural Vegetation

While erosion processes can take place naturally, everywhere in Chile, soil degradation in arid, semi arid and sub-humid areas is due mainly to adverse human action. Strategies to combat desertification should include the formulation of soil conservation plans. While the principal objective of such plans is to deal with the causes of soil erosion, they also prevent and control the direct impacts of desertification.

Erosion processes

Erosion originates when man destroys vegetation cover. The soil is left without its water retaining capacity and particlulates are carried away by rain water. Erosion is a process of degradation which is detected only in its final phases when its intensity reaches large proportions. The economic consequences of erosion include lower crop yields, which lead to a slow and constant process of impoverishment and rural migration.

National dimension of erosion

The total area of eroded lands is around 34,490,600 ha., representing 45.5 per cent of Chilean territory (Table 4) and around 75 per cent of the productive soils of the country. Of the total area affected by erosion, 80.5 per cent suffers moderate to serious erosion, meaning that soils have lost 40 to 100 per cent of their productive layers.

Table 4 : Erosion by Regions (CIREN, 1979)

Table 5 : Intensity of Erosion

The principal causes of erosion are indicated in table 7.

Table 6 : Causes of Erosion by Region

On the basis of a study done by CIREN-CORFO (1979) at 1:5000.000 scale from LANDSAT imagery, areas under erosion are presented in table 7 by macro-region.

Table 7 : Erosion Distribution by Macro-Region

ELEMENTS OF A NATIONAL STRATEGY TO COMBAT DESERTIFICATION

Cooperation Between Private and Public Sectors

Environmental Legislation

The following are examples of current legislation of interest in combating desertification: The Forestry law DS-4363 of 1931, The Protected Species Law DS-366 of 1944, The Agriculture Protection Law DL-3557 of 1944, The Protected Areas System Law DL-SNASPE, The Forest Promotion Law DL-701 of 1974 and The Irrigation and Drainage Promotion Law 18.450 of 1985. (As a result of this legislation, an area of over 14 million hectares, or close to 20 per cent of Chilean territory, is conserved through a system of protected areas.) Other legal instruments are under consideration, for example The Environment Law.

Participation of National Communities

Environmental Education

Research and Technology Transfer

Most dryland research in Chile has been developed under governmental support, with increased intensity from the 1950s to the 1970s, through the Corporacion de Fomento de la Produccion.

One impressive programme is the reforestation of woodlots in the Pampa de Tamarugal with Prosopis tamarugo, covering around 25,000 hectares in one of the driest deserts of the world. Since the 1970s, research has also concentrated on the production of horticulture crops and high value products (grapes, nectarines, kiwis), aiming in most cases to increase exports. Another major development concerns reforestation with direct and indirect support from the Government. Finally, the Fog Condensation Project should also be highlighted. Established in the area of Chungungo in the IV Region, this project has gained worldwide recognition as a means to provide water for local agriculture and community consumption.

FORMULATION OF A NATIONAL PLAN TO COMBAT DESERTIFICATION

This plan will include the following sections

i. Diagnosis, objectives and basic approach;

ii. Proposals for combating desertification;

iii. Current projects and proposals for new projects;

iv. Launching and evaluation;

v. Selection of consultant firms and institutions to be involved;

vi. Regional and national workshops;

vii. Final elaboration and publication; and

viii. Promotion of the plan as "Greening Chile."

The plan would have the following general objectives:

i. Underline desertification as an element of national environmental policy within the economic development of the country;

ii. Develop projects to combat desertification, ensuring the participation of national organizations and society;

iii. Coordinate current actions and programmes which would support implementation of the NPACD; and

iv. Create necessary coordination mechanisms or reinforce existing ones to ensure implementation.

The Chilean Government has now ratified the Climate Convention and the Convention on Biodiversity and is also taking measures to ensure the application of Agenda 21.

THE BRAZILIAN EXPERINECE IN COMBATING DESERTIFICATION AND ITS IMPACTS

Presented by : Mr. Paolo Roberto Franca, Division of Environment, Ministry of Foreign Affairs, Brazil

The existence of desertification processes in Brazil began to be more intensely discussed in 1977. Although little progress has been made in understanding the mechanisms which control these processes, some important studies and reports were prepared in different states, with technical and financial support provided by the Northeast Development Superintendency (SUDENE) and the Ministry of Environment.

The regions most susceptible to desertification in Brazil are located in the Northeast. However, significant erosion processes, loss of the vegetal cover, and formation of sand dunes have been detected in other regions such as the State of Rio Grande do Sul, where the climate is humid or subhumid.

The Brazilian semiarid region comprises an area of approximately 900,000 square kilometers, corresponding to 54% of the Northeast region and to 11% of the Brazilian territory. The climate in the region is characterized by rains concentrated in a 3 to 5 month period and the average annual rainfall varies from 400 to 800 mm. The rainfall distribution is very irregular in space and time: in some areas, the average is 250 mm, while in others it is higher than 1,000 mm. The mean annual temperatures are high (23 to 27 degrees centigrade) and the daily thermal amplitude is 10 degrees centigrade. The mean insolation is 2,800 hours per year, the relative humidity averages 50% a year and the mean annual evaporation is 2,000 mm.

This area is basically characterized by nearly impermeable crystalline terrain and very dry sedimentary terrain, which strongly determine economically exploitable volumes of water. The soil is mostly shallow and litholic, with a topography varying from mild to very wavy and with low water- retaining capacity.

In spite of the predominance of xerophytic species, the vegetation cover is extremely diversified. The prevailing specie in the semiarid region is the one known as "caatinga". According to different local ecological factors, other types of vegetation are found, such as the "cerrado" (savanna), dry woods, and riverine forests.

The local fauna is mostly made up of small animals with nocturnal habits. On the one hand, its diversity is limited by climatic adversities; on the other, it is stimulated by the heterogeneity of the region's microhabitats. Presently, many species are threatened by extinction due to predatory and subsistence hunting, deforestation and slash-and-burn activities, which destroy areas where animals build their nests and find their food, deeply changing their ecological niche.

The population of the semiarid region (approximately 26.7 million), which corresponds to 63% of the Northeast's and 18% of Brazil's population, is mostly made up of traditional ruralists with little or no access to the market, with extreme difficulty in absorbing new technologies and with old, deeply-rooted living habits. An exception to this rule is the relative growth of rural sectors linked to large export industries or urban sectors.

As in all Brazil, the Northeast region began to be occupied from the shore. Its development was based on extractive activities (timber) and on the production of export agricultural products (sugarcane). In the 17th century, livestock activities began to be developed in the semiarid backlands (the "Sertào"), giving rise to the establishment of the first urban centres.

Presently, mixed subsistence farming and cotton cultivation (which lately has been deeply affected by the boll weevil pest) are the main activities developed in the "Sertào". In addition to climatic adversities, traditional agriculture there is facing productivity and market problems. Corn, manioc, beans, sugarcane, rice, and cotton are some of the basic products cultivated there, among which corn and beans stand out as basic items in the diet of the rural population.

Because the soil continues to lose its fertility, cattle-raising has become the main activity in many areas. Practiced on a large-scale, it leads to the concentration of land tenure and stunts the production units, favoring rural exodus. It is mainly based on the use of natural pastures which grow during the rainy season. Oxen, sheep, and goat farms are commonly found.

Since 1970, irrigated agriculture activities have been officially stimulated, particularly by the state-owned Company for the Development of the Sào Francisco River Valley (CODEVASF) and the National Department of Public Works Against Drought (DNOCS). In 1980, irrigated areas in the Northeast comprised 261,000 ha, or about 17.6% of Brazil's total irrigated areas. Presently, 750,000 ha of northeastern lands are irrigated. In spite of positive expectations with respect to irrigation, an average of about 20% of the irrigated areas are facing problems of salinization, compaction, or floods.

The local climatic restrictions were determinant in the process of occupation of the land. As a result, the first places to be more intensely occupied were in more humid ecosystems, which, in most cases, are located in mountaneous regions. Steeper slopes, in general, caused intensive erosion processes, destruction of the most exuberant vegetation cover, and silting of water resources.

Due to the unique characteristics of semiarid climates, drought, although not always predictable, will remain a likely phenomenon. Studies carried out by the Aerospatial Technological Center (CTA) based on data covering a period of 129 years show that the critical periods had a mean duration of 7 years. The drought of 1970 affected 604 out of the 1,247 existing municipalities, involving a total area of 573,469 square kilometers and 7.7 million peoples. When combined with desertification processes, the harmful effects of the climatic manifestations of drought are multiplied.

The semiarid conditions prevailing in the Brazilian Northeast are a source of natural biotic retrocession processes in long drought periods which, added to old and intense anthropenic pressures, have been forming areas of irreversible edaphic and biotic degradation. Since the 70's, the State of Piaui has been invaded by large livestock projects. Due to their devastating effect on the native vegetation cover, they led to intense erosion processes which, in turn, drastically reduced the productivity of the soil and silted the main water resources. The action of these large projects, along with mining activities, extensive cattle-raising, and slash-and-burn practices, created one of the largest continuous desertification areas in the Northeast in the region of Gilbues, which covers an area of 1,240 square kilometers and 4 municipalities.

In the State of Bahia, large areas were identified where vegetation is becoming scarce and the soil is unprotected, with signs of rapid erosion. In the State of Pernambuco, an area of 25,000 square kilometers, that is, 28% of the State's surface area, was identified. In the State of Rio Grande do Norte, unfavorable climatic conditions characterized by low rainfall (400 mm/year), mining activities for the manufacture of clayware, and the removal of the vegetation cover for fuelwood are factors acting together to make the Seridò phytogeographical region one of the most serious examples of the desertification process.

In the State of Cearà, the establishment of an economic development model exclusively based on the monoculture of cotton led to the deforestation of huge areas. This provoked the soil laminar erosion. It also created conditions for the development of pests (boll weevils) which dramatically affected crops and caused economic and social damages beyond repair. An area of 1,400 square kilometers was identified in the municipality of Iraucuba and surroundings with signs of desertification.

It should be mentioned that, except for cases related to the States of Cearà and Piaui, the data gathered on desertification processes refer basically to 1978 and 1979. In the last decade, the Federal University of Piaui, supported by SUDENE and the National Council for Scientific and Technological Development (CNP), has carried out assessment and follow-up studies on affected areas. In 1990, relying on significant funds provided by the Studies and Project Finance Agency (FINEP), the Center for Desertification Research and Control in the Northeast was created and, in partnership with the Ministry of Science and Technology, the Ministry of Environment and the Ministry of Education, the 1st Course on Desertification in the Northeast was implemented as a basis to form and consolidate other teams. The Meteorology Foundation of the State of Cearà (FUNCEME) has also been carrying out serious work to prevent and combat desertification.

According to data on the droughts of 1951, 1958 and 1970, losses in food production and cash crops in the Northeast States varied up to 67% in those years, depending on the crop and the region. More recent data show that drought reduced the cultivated area, significantly reduced the production of grains, lowered the income of producers, and increased the prices of food products in the market.

Among the economic effects of drought and soil degradation, special mention should be made of a drop in agricultural/livestock production. In addition to reducing the income of the primary sector, the lower productivity of staple crops forces food industries to import raw materials from other regions of the country, increasing production costs.

There has been a disruption of rural life and economy, with effects on employment levels in the primary sector, which has not grown at the same rate as that of the population. While employment grew by only 0.4% a year in the 70's, the population grew at a rate of 0.53% a year. This unemployment rate, due mainly to the stagnation of economic activity in the region, is one of the factors which causes rural outmigration.

This dynamic spatially displaces populations which do not find means to solve their problems in their respective regions and end up migrating. As people migrate, they also transfer income to more developed population centres. Therefore, in this case, migration reflects both structural and environmental problems. When income opportunities and access to the market are limited, there is a tendency to over exploit the soil, with negative medium-and long-term effects on the environment and consequent rural exodus and urban growth.

The rural exodus does not put an end to problems caused by drought and degradation of the environment. After leaving the countryside, the inlander ends up joining thousands of others in the slums of big cities of the country. With limited or no skills to work in urban areas, he often becomes a social burden.

Hunger and endemic diseases are other negative consequences of drought and environmental degradation. In addition to hunger and malnutrition, chronic diseases such as gastroenteritis and pneumonia, are common in rural areas of the Northeast region. Together with the low educational level of the population and the lack of adequate medical assistance, these diseases are responsible for the high child mortality rate registered in the region. In years of drought, this rate is even higher. Recent data show that in a year before the drought, 1977, the child mortality rate was 4.7% while in 1984, the year that immediately followed the drought of 1978-83, the rate increased to 6.3%.

Several bilateral and multilateral assistance programs were implemented in the Northeast with the aim of lessening the effects of drought. Among these programs, the following ones stand out:

i. Bilateral technical assistance programs with Italy, France, Spain, and Israel in the areas of irrigated agriculture, utilization of surface and underground water resources, and utilization of solar and wind energy; and

ii. Technical cooperation programs with international organizations such as FAO (technical assistance to irrigation projects and evaluation of salinization potential), ORSTOM (studies for the utilization of surface waters in small ponds), UNDP (adequate irrigation management through agrometeorological models), and ICRISAT (development of technologies and species of plants adapted to drought conditions).

International financial organizations, such as the World Bank and the Interamerican Development Bank, also have been providing support to irrigation projects, urban and rural sanitation works, ponds and dams, agro-industries and other social activities.

The Brazilian institutions in charge of executing the principle irrigation projects in the northeast region have implemented, in recent years, more than 50,000 irrigated hectares. Some of these projects are successful, such as the Petrolina-Juazeiro complex, which is producing and exporting cash crops, such as fruits and vegetables, taking advantage of ideal climate and soil conditions. Altogether, there are now about 750,000 irrigated hectares in the region, which directly or indirectly benefit a population of 3 million. Unfortunately, the area covered by these projects is still small, as it corresponds to only 12% of the region's potential irrigated areas.

Analyzing the results attained by the principle regional programs to mitigate the effects of drought, positive and negative aspects arise, as well as important conclusions, among which the following stand out:

i. In the last century, the understanding of the drought problem and the formulation and implementation of governmental policies have evolved positively;

ii. The drought issues should not be treated separately from regional development issue. The only way to diminish drought's effect on the population is to promote the socioeconomic progress of families in production units. In this regard, the development of the agricultural sector based on modern techniques, such as irrigation, is more effective than the risky and mainly rainfed traditional agriculture still practiced in the region;

iii. In spite of the positive results produced by some regional development policies, and by policies aimed at combating the effects of the drought, most of the rural population remains as vulnerable as before.

Generally speaking, the causes of desertification in Brazil are not different from those normally observed in other areas of the world. They have been almost invariably related to the inadequate use of resources and to short-term regional development models. These short-term regional development models are induced by the international economic environment which accentuate unsustainable agriculture and poverty in dryland areas. The declining prices of agricultural commodities, world trading patterns and problems related to the debt crises have a bearing on the definition of development policies.

In conclusion, we can say that desertification has reached a dramatic level in Brazil. Its expansion is responsible for the loss of considerable productive capacity.

Out of the 900,000 square kilometers of the semi-arid region, 227,000 square kilometers (24%) are affected by desertification processes. The population directly affected is approximately 2.7 million inhabitants, which correspond to 10% of the Northeast's population. The population affected by drought is 15 million people.

The loss of the productive capacity stimulates the expansion of the agricultural frontier and the migration process. The latter affects the rate of population growth in urban centers beyond their capacity to provide basic services. The negative socioeconomic impact of this situation, which degrades the quality of life, can be felt on all levels of the national life.

THE MEXIAN EXPERINECE IN COMBATING DESERTIFICATION AND ITS IMPACTS

Presented by : Mr. Manuel Anaya, Secretaria de Desarrollo Social, Mexico

INTRODUCTION

Desertification - Problem in Mexico

Desertification means dynamic processes which physically, chemically and biologically degrade ecosystems, sometimes irreversibly, and cause social, economic and political consequences. Some natural factors, like undesirable cultivation practices and increasing population pressure, have provoked the impairment and destruction of the land`s biological potential, reducing plant and animal productivity, and bringing on desert conditions.

Population and Desertification

Today, a growing national population is endangering the ecosystem`s productive capacity as indicated by the relentless spread of desertification. In Mexico population is growing at a faster rate than food production, and malnutrition is prevalent in many underdeveloped communities.

This concentration of people promotes the rapid deterioration of ecosystems due to immoderate felling, uncontrolled cutting of firewood, overgrazing, reduction of vegetation cover and exposure of top soil to wind and water erosion; thus the productivity of the ecosystem is reduced, ecological deterioration is increased and the abandonment of land is promoted. This occurs in the central part of Mexico, where desertification outpaces land reclamation.

The Advance of Desertification

It is estimated that overgrazing has damaged more than 60 million hectares of the National Territory and that these lands exhibit the worst deterioration. In the second place, with regard to area covered and damage inflicted, are forests, which have suffered from badly-planned felling, uncontrolled cutting of firewood and fires. In third place is dryland agriculture,which occupies around 21 million hectare and where wind and water erosion are prevalent. Finally, irrigated agriculture occupies 5.8 million hectares and poses dangers of salinity, lack of drainage, marine intrusion, over-exploitation of water resources and accelerated silt build-up in reservoirs. As a result of these processes, the rate of advancement of desertification in Mexico today is faster than the rate of recuperation of affected areas and represents a danger for the sustained production of food.

The above-mentioned land uses are not the only ones that pose risks of desertification. Desertification problems may also arise from other soil uses, such as national parks, ecological reserves, roads, mineral exploitation and human settlements.

In Table 1,some of the physical, chemical and biological processes which cause environmental deterioration are presented, and some of the problems of water, soil and plant management are analyzed. The principal desertification processes are : 1) reduction of vegetation cover, 2) wind erosion, 3) water erosion, 4) deterioration of soil structure, 5) reduction of organic matter, 6) salinity, and 7) lack of drainage.

The above facts indicate the need for adequate integrated planning for the use of water, soil, flora and fauna resources with the objective of preventing desertification, reducing ecological deterioration, assuring sustained food production and promoting better social development.

Table 1 : Physical, Chemical and Biological Processes which Cause Desertification (* Natural Causes)

ENVIRONMENTAL CHARACTERISTICS OF MEXICO

Mexico is located between 15 and 32 degrees north latitude, covers an area of about two million sq. km, and has a population of about 82 million people. It has boundaries, with the United States of America on the North, the Gulf of Mexico on the East, the Pacific Ocean on the West, and the Republic of Guatemala on the Southeast. More than two thirds of Mexican Territory is arid or semiarid, where human activity depends upon low, seasonal and variable rainfall, and the zones are vulnerable to drought and other climatic variations.

There is a significant geographic mismatch between water resources and population in Mexico; only 12% of the nation`s water is on the central plateau where 60% of the population and 50% of the basic cropland are located.

Mexico, before the Spanish Conquest, during the Viceroyalty and after the War of Independence, always appreciated the importance of water availability, the importance of controlling water flow and the creation of socioeconomic infrastructure for supporting an equilibrium between industrial, urban and agricultural systems.

Biodiversity in Mexico has its origin in 52 different types of vegetation communities. Besides differences in culture and social aspects, increased diversity, is an important factor to be considered for national development. Environmental deterioration has been induced by man`s activities, and natural cycles have been changed with the consequent degradation of many ecosystem's.

Regions of Mexico

According to Tamayo (1976), there are 37 hydrological regions. Mexico also has a variety of vegetation units and land use systems. Finally, the Department of Urban Development and Ecology (1985) proposed four ecological regions: arid, temperate, humid tropic and dry tropic.

The Principal Soils of Mexico

One of the natural resources of high significance for human life is the soil, because of its direct relationship to agricultural land use. Knowledge of this resource is indispensable for planning development in any country.

In accordance with the criteria established by FAO, three main climatic divisions have been defined in Mexico: the Low or Warm Lands, with an altitude of less than 1,500 m and a mean annual temperature higher than 20 C, covering 86% of the Mexican territory; the High or Temperate Lands, with an altitude of 1,500 to 3,000 m and a mean annual temperature ranging between 10 and 20 C, covering 13% of the country; and the Very High or Cold Lands with more than 3,000 m of altitude and less than 10 C mean temperature, covering less than 1% of the total surface of the country.

Land Use Systems

Land use systems in Mexico are highly influenced by topography and climate. With two important mountain chains running parallel to both coasts, and a volcanic axis crossing the country along the 19th parallel, a high percentage of the total area has steep slopes, limiting agricultural activities, as indicated below:

Land slope %.................................Percent of total are

0 to 10.......................................................36
10 to 25.....................................................36
More than 25.............................................28

With regards to climate, the north central and northwestern zones are arid and the southern region is humid. Desertic, arid, and semiarid areas occupy 76% of the country; 21% correspond to semi-humid and 6% to humid and very humid areas.

Land Use Systems in Mexico

POPULATION

In 1940 the population or Mexico was 19.6 million inhabitants. In 1980 it reached 66.8 million, in 1992 84 million. It is estimated that it will be 108 million by the year 2000. The highest population concentration is in the Neovolcanic Belt in the central part of Mexico where in 20% of the national territory, 60% of the total population is located.

DESERTIFICATION IN MEXICO

Desertification in Mexico was evaluated at a scale of 1:2.000,000 to analyze land degradation processes such as: water erosion, wind erosion, salinity, sodicity, lixiviation, diminishing organic matter, rusting and soil compaction. Results showed that more than 85% of the National Territory is affected by desertification at different levels from the slightest to the most severe. Land degradation processes were estimated in 16 physiographic regions.

Desertification processes in Mexico are caused by the following factors: deforestation, overgrazing, overexploitation of aquifers, erosion, salinization, diminishing organic matter content, reduction of soil depth, and contamination. These processes are related to population density. In this regard, the central part of Mexico, covering 20% of the national territory, has 60% of the total population. In the neovolcanic belt and with arid, semiarid and subhumid zones, it is the most affected area of Mexico.

Arid zones located mainly in the North of Mexico are prone to desertification processes due to: erosion, intensive systems of exploitation of natural resources, drought, poverty and low education levels.

In Mexico, arid and semi-arid zones account for 70% of the national territory. There, 14 million farmers have little possibility of working the land they were born on, and every year 900,000 move to urban areas.

About 170 million hectares of Mexican land roughly 85% of the national territory, show some degree of desertification. From 150 thousand to 200 thousand additional hectares are degraded each year.

Among the many factors which produce desertification in Mexico, political decisions made solely in the interest of urbanization and industrialization take a heavy toll.

Mexico currently farms 22 million hectares of its land, 75% under rainfed conditions. This is a potentially dangerous situation since, given the projected population of 108 million by the year 2000 and an upper limit on arable land of about 25 million hectares, the country will have an average of only 0.23 hectares per capita at its disposal. If adequate measures are not taken, famine will surely result.

IMPORTANT CONSIDERATIONS IN INTEGRATED PLANNING AND USE OF NATURAL RESOURCES

Water and Land Available for Agricultural Purposes

The correct management of water and soil represents the basic infrastructure to achieve permanent agricultural production systems. The most important limiting factor for the development of arid and semi-arid zones has been, is and will be water. The principal uses of water, in order of importance with regard to volume consumed, are: agricultural, industrial and domestic. Some countries, such as Mexico and India, use more than 80% of their water for agricultural purposes and less than 20% for industrial and domestic uses; others, such as Russia and the U.S.A., use about 40% for agriculture, 45% for industry and the remaining 15% for domestic purposes. The estimated demand for industrial purposes is 20 - 40 m3 per person/year, which is comparable to domestic consumption in developed countries.

Land Ownership and Parcel Size

Insecurity over land ownership causes socio-economic problems in agricultural and forestry production systems and, in the majority of cases, diminishes production. Other problems arise when parcel sizes are very small and have a low production capacity. This causes the farmer to seek other work and partially or totally abandon the parcel.

On many occasions, soil erosion affects various parcels and necessitates the participation of a group of farmers for its effective control before it continues and affects other parcels. The abandonment of parcels produces low-remuneration marginal areas and at the same time favors desertification processes. It would be desirable to consider each community as a production unit and make it responsible for the rational management of its natural resources. In the case of lack of food, the best land should not be dedicated to the production of highly remunerative crops and the marginal land to food production. Therefore a rational plan of action should be established to assure the production of basic food crops.

Input Availability

All land-use systems require the availability of certain inputs (e.g. credit, fertilizers, mechanization, seeds) in order to improve productivity and prevent the development of desertification. Unfortunately, the most degraded land-use systems require high investment. When such investment is not forthcoming, a vicious circle is initiated which results in ever-worsening desertification, principally in the communities with a low development capacity.

Extensive production systems with low productivity per unit of area and per unit of time are the most widespread in Mexico. Therefore, plans of action for the short and long-term are urgently needed to induce a gradual change to more intensive production systems with greater unitary yields. The technology utilized should be chosen to facilitate this transition in order to augment production and profits - part of which should be reinvested in these production systems. Security in the improvement of the standard of living for the population would motivate them to work with more enthusiasm and to stay within their communities - so reducing the massive migration to urban centers.

Mechanization Levels

In developing countries like Mexico, it is frequently found that the principal energy sources in land-use systems are man and animals, which, in the majority of cases, do not satisfy the energy demands for opportune execution of certain agricultural activities. Greater efforts should be made to develop traditional equipment and tools by means of an industry that evaluates, designs and produces the necessary tools at a local, national and international level.

STRATEGIES TO CONTROL DESERTIFICATION

International Level

The world strategy to prevent and fight against desertification is contained in the plan adopted at the World Conference on Desertification which took place in Nairobi, Kenya in 1977, and was organized by the United Nations Environmental Programme. It was agreed that each country should establish a National Plan to Combat Desertification. The integrated planning system recommended above and the control of desetification should function in parallel as they are both related to the appropriate use of water, soil, flora and fauna resources - the important heritage of present and future generations.

During the Nairobi Conference, short and long-term principles and measures were established for the prevention of and fight against desertification. It was considered a problem for humanity, therefore, the success of the fight would depend upon the organized and enthusiastic actions of the communities which are responsible for the use of natural resources. The Action Plan should be integrated and measures should consider appropriate technological levels for production systems, as well as ecological, social and economic conditions.

To date, Mexico and the U.S.A. have made an agreement to improve the management of arid and semi-arid lands and to control desertification. They have shown concern as the phenomenon of ecological deterioration represents a growing threat to the economic and political well-being of the inhabitants of both countries. This agrees with the approach of Agenda 21.

Elements of a Plan to Combat Desertification

Some actions to help fight against desertification are the following: 1) selection of appropriate technology, 2) establishment of a Plan, and 3) setting-up of pilot areas.

It is crucially important to count on the support of the local population, as the objective is not only to fight against desertification and promote economic growth, but is also related to the morale of the people, especially in the most seriously affected areas where misery, unemployment and under-development are present.

Technology and Desertification

Desertification is a phenomenon promoted by man and caused by exceeding the potential limits of desertification which exist for various land-uses. Any land-use by man signifies a potential danger for the system; selection of appropriate technology tends to minimize this danger and increase productivity.

Desertification is often caused by the need for man to subsist and many other times by the desire to overexploit natural resources. Technology represents a link between natural and social systems and may or may not result in the optimum management of natural resources. There are many examples of the correct and incorrect application of technology and cases where the wrong application of technology has been responsible for many environmental problems, of which desetification is only one.

Technology can be considered as simple, intermediate or advanced, depending on the established reference framework, although simplicity is not necessarily related to traditional or primitive technology. Appropriate technology can be, from the point of view of its complexity, simple, intermediate or advanced, and therefore a particular technology may be appropriate under certain specific conditions and inappropriate under others.

To date there exists a great variety of technologies generated by empirical and scientific know-how; it could be said that in general there is no limit to technological solutions to the problems of desertification. In the majority of cases, the factors inhibiting efforts to combat desertification are social, economic and political.

The selection and application of technologies to fight against desertification in Mexico will depend upon the education and motivation of the local population, the availability of well-trained technical personnel, levels of investment and the time dedicated to the recuperation of specific areas under the process of deterioration.

Three basic principles should be taken into account to determine the most efficient technologies.

First, the logical sequence to begin to fight against desertification is to give priority to the least deteriorated production systems. This is especially important in those situations where economic limitations are severe, since limited investment could produce satisfactory benefits over short-term periods which could then be reinvested to increase productivity gradually. Also, the extra profits could be used to recuperate other more severely damaged areas.

The second principle refers to the consideration of intermediate technology concepts, always given that this is possible. Frequently developing communities are associated with reduced industrial capacity, a lack of health centers in good condition, low credit availability and poor technological development, all of which hinder the introduction of more advanced and complex technologies. Some characteristics of appropriate or transitional intermediate technology are the following: 1) a high sense of social justice, 2) adaptability to social and human group behavior, 3) capacity for successful technological combinations complemented by old and modern know-how and experience, 4) low cost, 5) slight negative effects on ecosystem, 6) more efficient use of local manpower, and 7) generation of gradual growth which is more realistic for the social and economic systems of a locality.

Thirdly, traditional technologies developed by communities, as well as other life systems, should be considered before the establishment of new land-use systems, as these have been proved over long periods of trial and error and represent proven bases for the management of natural resources. Frequently this local experience provides the starting point for the fight against desertification and the generation of development. Furthermore, when traditional technology is complemented by that of an intermediate and modern character, the capacity exists for a creative and gradual change from an extensive, low-yield system to one of intensive production.

It is important to emphasize that technology per se is not sufficient to control desertification. It is also necessary to count on an adequate basic infrastructure and, even more important, to achieve the enthusiasm of the people and their decision to participate in the process.

Principles for a Plan of Action to Control Desertification

A plan is one way to organize action for the control of desertification and is related to the planning of the following: prevention, reorientation, systemization and evaluation. A plan can comprise various action programs and the area considered can be at national, state, local, or municipal levels.

The components of a plan are the following: 1) diagnosis, 2) prognosis, 3) objectives, 4) levels of application, 5) levels of coordination, 6) plan of implementation, and 7) evaluation.

1. Diagnosis. This refers to the evaluation of that which has happened in the past. It should consider the availability of water, soil, flora and fauna, the socio-economic framework, which shows the current conditions and capacities of the population, and the legal and administrative framework which defines the legal and organizational bases for the fight against desertification. This evaluation should consider indicators of desertification which could be grouped as follows: a) physical and biological, and b) socio-economic. Current methodologies are very diverse and are related to the use of satellite imagery, aerial photography, land survey backup, and mathematical models. The scale at which each of these methodologies is applied plays an important role. The diagnosis is a very significant component and on this depends, to a great extent, the success of the plan to prevent and combat desertification.

2. Prognosis. In this component, general and specific trends will be analyzed with the idea of forecasting the advance of desertification. Also some preventive and corrective propositions could be considered.

3. Objectives. These can be both general and specific and refer to what needs to be done in the short, medium and long term, as well as state working hypotheses.

4. Application level. This refers to how the plan will be carried out according to available instruments, such as policies, strategies, legislation and methodologies to employ. The control of desertification could be achieved by utilizing a massive application of science and appropriate technology. Extension programs to facilitate the introduction of technologies could be strengthened.

5. Coordination with other planning levels. Coordination and organization are essential ingredients for the harmony of short, medium and long-term actions. Currently, there are numerous programs for the fight against desertification in which the participation of the public and private sectors, of communities, and of technicians, is observed. Nevertheless, it is necessary to improve organization and coordination considerably.

6. Operation. The organized participation of communities, technicians and private and public sectors will be sought. Negotiations will be carried out at municipal, state and federal level with the idea of covering the various levels of operation and execution.

7. Evaluation. This will give a continuity to the plan with the object of carrying out periodic evaluations which allow the reorientation and refinement of actions against desertification.

Mexican Experience in Pilot Projects

The establishment of pilot areas to combat desertification serves three objectives: 1) research, 2) demonstration, and 3) training at various levels. Pilot areas contribute to finding viable strategies which help to impede ecological deterioration and maintain the productivity of ecosystems. An evaluation should always be carried out in order to assess the advantages of the trial and, above all, for economic, social and ecological reasons.

Another important aspect is the setting of pilot areas; these areas should be representative of the most important ecological and socio-economic conditions. Pilot areas should not be as small as an experimental field, nor so large that they cannot be controlled easily.

Enthusiastic participation of the community and the public and private sectors will be indispensable for the achievement of objectives. Properly chosen pilot areas will serve as the base for the establishment of programs on a larger scale, which will be an important part of a global pattern to control the process of desertification.

In Mexico there is an interesting experience with this, as several pilot areas have been selected in regions with varying ecological and socio-economic characteristics and which form part of the states of Sonora, Coahuila, Zacatecas, Guanajuato, Mexico, Oaxaca and Tabasco.

In each one of the selected states, a regional reference framework was established, taking as a basis the municipality in which the proposed pilot plant would be located. The regional reference framework includes the following: 1) physical characterization of the area, 2) socio-economic aspects, and 3) production systems.

Once the regional framework is analyzed, the specific area is selected through field trips and, with the support of the local people from participating institutions, the following points are considered:

i. That the chosen area, where possible, be a hydrographic basin, for the purposes of measuring the incoming and outgoing water and the sediment losses which occur in the zone, considering the basin as a production system and as an ecological unit;

ii. That the chosen area present various land-use systems so that an evaluation can be carried out for each one of them regarding their impact on the degradation of the resources, as well as their recuperation potential; and

iii. That their ecological conditions be representative of the region in which they are located so that results may be extrapolated.

The phases of the pilot project area are: 1) elaboration of the reference framework, 2) diagnosis of the problem, 3) detection of preventive and corrective measures, 4) presentation and approval of investment projects, 5) carrying out of works, research and training at various levels, and 6) evaluation.

Complementary Strategies to Attack Encroaching Desertification and Drought

i. Establishing long and short-term programs in forest zones, pasture lands, rainfed and irrigated farmlands, and areas under nomadic cultivation. (Other land use systems are roads, national parks, human settlements and mines);

ii. Employing the watershed as an ecological, hydrological and production unit for concerted action by communities, technicians and institutions;

iii. Promoting a national, state and municipal technological information network to allow the effective exchange of experiences from diverse social, economical and ecological backgrounds; and

iv. Promoting collaboration between scientists and technicians from all areas of study, as well as national and local planning to fight desertification through a Scientific and Interdisciplinary Consultive Committee on Desertification Control.

CONCLUSION

By the year 2000, there will be 108 million human beings in Mexico, each and every one will require food and acceptable living conditions. So, real social and economic development will be the only way to prevent and combat desertification. However, if natural resources continue to be squandered, Mexican territory will soon be nothing more than a lifeless desert incapable of providing for basic needs. The battle against nature and man himself is an uphill one; yet, all is not lost and hope of victory remains through joint efforts to save our children from a future of misery, poverty, famine and death.

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