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III. Problems of management of arid zones in South America
In Session IV four speakers addressed the problem of arid lands management in South America, namely Dr Manuel Correia on the Nordeste of Brazil, Dr Amaro Zavaleta on Peru, Dr Rolando Braun on west-central Argentina, and Dr Juan Gastó on Chile.
Dr Correia stated that land use in semi-arid northeastern Brazil had traditionally combined extensive grazing with subsistence cropping on temporarily flooded river plains. From 1930 the introduction of mechanized irrigation farming and the improvement of transport and communications permitted the development of commercial crops, under which system the peasants became share-croppers and the land-owners provided seeds, fertilizer, and pesticides and handled the marketing of the produce.
Recurrent droughts and the natural increase of population led to government intervention aimed at controlling excessive outmigration, through agencies for drought-control, agricultural research, development, etc. The drought-control agency soon became involved in the construction of large reservoirs. This was accompanied by the expropriation of land, both upstream and downstream, for the area to be covered by the reservoirs and for that to be converted to commercial cropping, in both areas displacing peasants practicing traditional subsistence agriculture.
This policy, although apparently technically sound, had serious social consequences. Since the small peasants generally had no title to the land they had traditionally occupied, they were not entitled to compensation payments for expropriation. Their only option was to migrate to the towns and cities, where they had to live from occasional work, begging, or prostitution. Land irrigated from the newly built reservoirs was sold at prices too high for the peasants, and large enterprises, mainly from southeastern Brazil, became the main beneficiaries, acquiring large tracts of land and obtaining credit from the government and from private banks. The former smallholders, now dispossessed, were forced into working for wages. The only forms of peasant agriculture left in these areas are some cooperatives, as at Bebedouro and Petrolina, but they have not received sufficient support and consequently are not very successful.
The UN University could well support a research programme in this area, examining not only the processes of transformation from traditional to modern agriculture but also the problem of peasant participation in decision-making. Such a programme should aim to identify closely with locally perceived problems and obtain the co-operation of the local population, which might benefit from its results. It could benefit from the experience acquired by church agencies, which have been involved with the problem for many years.
The situation in the area has so far evolved along the lines of an economic model adopted by the government, under strong influence from technicians trained abroad and from advisers from more developed countries. This model has led to dispossession of the peasants and to a concentration of income in large companies. However, there is much current dissatisfaction with it, and changes should be proposed, for example concerning the role of the State and the need for greater emphasis on regional problems, such as outmigration in all its aspects, including resistance to migration; and on the role of the economist and the need to place less emphasis on purely economic analysis and more on the results of studies by social scientists. Economic-oriented planning has been looking at short-term solutions, but social and ecological problems need long-term planning. Solutions should take into account the integration of the poorer sectors of the community within the development process, taking advantage of the significant knowledge and skills that exist there.
In discussion attention was drawn to three problem areas cited by Dr Correia, namely those of migration in its broadest context, the need to embrace within the planning process the poorer sectors of the community, with their aspirations and perceived priorities, and the broad question of government policy in relation to large-scale development. It was asked whether any of these problems had been investigated by regional institutions and in what ways. For instance, had there been a multidisciplinary approach?
Dr Correia stated in reply that a number of research projects had been carried out by academic and other institutions with support from regional agencies such as Superintendencia do Desenvolvimento do Nordeste (SUDENE) and the Bank of Northeastern Brazil, or from national bodies such as Petrobas. However, although these projects had covered part of the problem he doubted whether they had conveyed a realistic vision. Rather, they had represented the viewpoint of agricultural research, separate from the social context. Contact with the local population had been almost non-existent, although certain institutions such as the Catholic Church and the F. Ebert Foundation had tried to involve local communities. A major problem was the concentration of power in the coastal cities of Brazil.
In his account of the Peruvian situation, Dr Zavaleta concentrated on the irrigated alluvial valleys of the coastal plain, emphasizing first the environmental limitations and secondly problems arising from man's use of resources. Among the topics he illustrated were:
- shortage of irrigable agricultural land and problems of urban encroachment upon it, as around Lima;
- shortage of water for irrigation, with the inadequacy of the coastal streams during the winter season, and increasing demands for urban settlements. This emphasized a need for improved methods of application of irrigation water in relation to crop needs and soil characteristics;
- waterlogging and soil salinization, particularly in the lower sectors of the alluvial valleys, in the absence of adequate drainage and aggravated by over-watering and poorly prepared lands;
- build-up of toxic elements in many soils, through the content of boron, arsenic, etc., in irrigation waters;
- deterioration of soil structure and soil-water relations through incorrect irrigation and cultivation practices;
- problems of crop disease, for example of citrus crops.
Dr Zavaleta explained that many of these problems had built up over a long period, but were also related to questions of tenure and management that had been particularly influenced by the land reform movement over the past decade. Among the topics of this kind touched on were:
- the impact of tenurial and land-management changes on irrigation systems, and particularly the failure of many co-operatives that had replaced former large undertakings to maintain adequate programmes of irrigation and management;
- inadequate agricultural extension services and credit facilities for the introduction and support of innovations and improved management practices;
- policies of depressed prices for agricultural produce, and unsatisfactory marketing systems;
- large-scale abandonment of agricultural land in the uplands, with consequent excessive outmigration, weakening of the rural communities, and disorganized expansion of the cities.
Dr Zavaleta referred only briefly to the problems of the extreme-arid inter-valley areas, which were little used, but mentioned the question of reestablishment of vegetation in the mist-fed Lomas belt, and the problem of local sand-dune stabilization using non-biological means, as well as planting where irrigation was possible.
Dr Braun pointed out that the semi-arid and arid zones of Argentina represented 60 per cent and 15 per cent respectively of the 2.8 million km2 of Argentinian territory, but supported only 15 per cent of a total population of 27 millions. There were important differences in land use and land tenure, but socioeconomic contrasts within rural communities were less marked than in other countries of Latin America.
In the Chaco-Monte and in Patagonia, water was the main factor limiting development-in the former area because of failure to manage the river systems and develop possibilities for irrigation based on surface waters, and in the latter because of the depth of the watertable. Soil erosion was another general problem, particularly in the torrential catchments of the Andean slopes and foothills, with a combination of steep slopes and excessive deforestation. Support for land development by the government and by banks had not generally been conservationist in outlook, and there had been inadequate finance for remedial management measures such as contour-banking. Little attention had been paid to reforestation of these areas. The natural vegetation had been severely depleted by wholesale rather than selective clearing, by uncontrolled burning, and by cutting for firewood, both for local needs and for export beyond the region.
Overgrazing was general in the semi-arid zone, where there was inadequate fencing and little management of forage resources, for instance to provide a surplus for inevitable dry years. The consequences had been a depletion of useful perennial shrubs, locally accompanied by invasion of species of little value, soil deterioration and erosion, and a marked decline in carrying capacity. In the uplands, transhumance dominated by goat-herding had led to severe devegetation along the migration routes which had been traditionally followed over a long period, and there was overgrazing and accelerated erosion, particularly on state lands. The maintenance of watering points was generally inadequate.
The native fauna had not generally been regarded as a resource, and adverse changes had followed the introduction of exotic species for hunting.
The problems described had generally arisen through lack of understanding of the physical and biological environment, with the result that there had been a lack of appropriate management. To this were added social and cultural factors, such as demographic pressure, poverty, and lack of education, which had hindered the provision of training and extension services.
In discussion it was pointed out that many semiarid countries, including Argentina, are important food-exporting regions, and that perhaps the role of food production should be re-examined in relation to resource management in the semi-arid zone. Another important problem was the movement into the zone of livestock from higher-rainfall areas. These were problems calling for multidisciplinary study.
Dr Braun replied that research into problems of the drylands of Argentina had been carried out by IADIZA, by the Comisión Nacional de Investigación Cientifica y Tecnológica (CONICET) through its station at Puerto Madryl in northeastern Patagonia, and by several universities. Problems investigated had included the ecological bases of rangeland improvement, and dune stabilization in areas of sand encroachment. Some studies of transhumance had been made, but he agreed that there was scope for further integrated research on a multidisciplinary basis.
Dr Gastó began his review of the Chilean drylands with brief accounts of the main regional environments and their limitations; he then summarized the major problems for management, and finally discussed the traditional solutions, together with alternatives raised by recent research.
He mentioned that the total area of the drylands of Chile was about 30 million ha and that they included the following environments:
-the high steppes of the Cordillera, consisting mainly of shrubsteppe of low productivity used for grazing of camelids, but including 10,000 ha of high saline meadows of greater value;
-the interfluvial sectors of the Atacama Desert, virtually rainless and unproductive. They included the Tamaruga Pampa in the north, with valuable groundwater resources (4 cumecs) that were practically untapped; otherwise there were the salares and the coastal fog-desert;
-the littoral terraces, which had good soils and which in the south received enough rain for productive land use;
-the Serranías, or steep Andean slopes, which supported an unproductive cactaceae and which had low rainfall (15 - 100 mm per yr), but which were subject to extreme erosion;
-the coastal hill ranges, which in the south offered good winter grazing and which were capable of improvement. Problems included high sulphur content and low phosphorus and nitrogen content of soils;
-the planezes of the Patagonian Andean slopes, which had valuable tussock grasslands but were little utilized;
-the cross-valleys of the coastal desert, which were the main productive areas, being under irrigation, but where there was much wastage of water.
The fundamental environmental problem was the low and irregular precipitation, with frequent drought, but there was a lack of appropriate adjustment to this climatic regime and to the changing needs of agriculture. For example, there was a poor response to seasonality in the use of the land, as in the failure to store the seasonal surplus in the southern part of the drylands. Where shifting cultivation occurred in conjunction with the grazing of livestock, it had destroyed the rangelands, whilst the cropping was unproductive. The main non-environmental problems were organizational weaknesses, such as a lack of planning in farming, and a lack of infrastructure, such as adequate fencing and watering points.
Dr. Gastó listed some possible solutions, together with their drawbacks in some cases:
- extension of irrigation. Water is limiting, but could be used more efficiently than at present;
- cloud seeding is ruled out by absence of clouds of suitable type;
- management of micro-watersheds is possible in the far south, but has limited effectiveness in areas of winter rainfall;
- adjustment of land use to the growth patterns and potential of the existing vegetation, and its transformation to improved productivity through management, is the favoured option in the rangelands;
- replacement of the natural vegetation would be too expensive in relation to the returns, particularly in areas with less than 300 mm rainfall, where experiments have shown it to be less effective than working through the existing plant successions;
- increased application of fertilizers has possibilities in irrigated areas and in regions with more than 300 mm rainfall, which have shown response to the addition of nitrogen and phosphorus;
- conservation of forage, including transport of surplus harvest from wetter to drier areas, and storage for bad years;
- animal improvement through breeding, perhaps without change of species presently used, and concentrating on the breeding of store cattle in the dry areas, which are climatically suitable and relatively disease-free;
- adjustment of stocking rates to the proved carrying-capacity of rangelands;
-adjustment of season of grazing and intensity of stocking as a counter against invasion by woody shrubs;
- afforestation of deforested areas;
- improved systems of crop-rotations, especially in areas of Mediterranean-type climate;
- extension of soil conservation practices.
Considering the implementation of such transformations, Dr Gastó suggested some basic questions that had to be answered; for example:
|What?||The soil and the native vegetation.|
|Where?||In the better areas, namely the subhumid zone and the irrigable tracts.|
|How?||Through gradual transformation of the existing vegetation, which would be possible through intermediate technology without the use of heavy machinery.|
|When?||This must depend on priorities in investment.|
The answer to the question "Who will pay?" presumably lay in the answers to other questions, such as "Who has the means?", "Who will be involved?", and "Who will benefit?".
Dr Schneider commented that the chosen solution must also depend on social and economic factors, such as land tenure and accessibility to services. One must work within the existing social framework, perhaps offering alternatives from which the local community might choose. Because of this, different areas in the same environmental setting may require different treatment. Generally, the proposed transformations will involve considerable social and economic changes, which will require external help.
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