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close this bookThe Fragile Tropics of Latin America. Sustainable Management of Changing Environments (UNU, 1995, 335 p.)
close this folderPart 4 : The semi-arid north-east
close this folderDrought, irrigation, and changes in the sertão of north-east Brazil
View the document(introduction...)
View the document1 Introduction
View the document2 Reservoir irrigation in Paraíba
View the document3 Middle São Francisco valley
View the document4 Consequences of irrigation agriculture
View the documentAcknowledgement
View the documentReferences

4 Consequences of irrigation agriculture

During the 1980s the sertexperienced a substantial transformation where irrigation water became available. In this paper we have observed two types of irrigation farming. Small-scale spontaneous irrigation farming is practised around reservoirs constructed on small rivers in Boqueirand Teixeira. After the caatinga vegetation is cleared and burned, the field is irrigated by pumping up water. Although such fields are limited in area and tend to shift after several years of cultivation, this type of intensive farming plays a significant role in the metropolitan markets of the North-East.

On the other hand, large-scale transformations are taking place in the middle SFrancisco Valley. With the influx of capital, manpower and technology, and with governmental planning and support, the PetrolinaJuiro area has emerged as a productive farming region known as "New California." It produces fruits such as melons, grapes, and mangoes, as well as tomato pulp, cotton, wine, sugar, and alcohol for the national and international markets. The region is a contemporary frontier of Brazil.

If sufficient and regular supply of water is secured, the dry tropical environment has great merits for farming free from plant diseases. Besides, abundant sunshine throughout the year promotes uninterrupted plant growth. The unexploited soils are fertile enough. The construction of better roads and the development of trucking have improved the serts access to the coastal North-East as well as to the south-eastern metropolises.

Although intensive farming in our study areas has only a short history of development, taking place during the last decade, various consequences are already observed. More time is needed to evaluate critically the total consequences of irrigation farming in the sert but it is worth while mentioning some effects that we observed in the field.

Irrigation farming has introduced a new land-use system. The longterm, extensive use of land was replaced by the repeated cultivation system. Plant diseases have started to appear and soil productivity has begun to decline. Thus, the yield per unit area is decreasing. Consequently some fields have already been abandoned. In order to cultivate continuously, pesticides and fertilizers are increasingly applied. In addition, effective crop rotation systems need to be introduced. In the spontaneous irrigation areas around the reservoirs in Boqueirand Teixeira, the system of crop rotation depends on the farmers' empirical knowledge, taking into consideration the ecological responses of crops to the soil conditions. For example, tomatoes are a typical short-term crop, and carrots and bananas long-term crops.

In the industrial farms of the middle SFrancisco Valley, on the other hand, careful study of the soil and of market conditions decides the rotation system. It can be practised only with substantial aid of pesticides and fertilizers. Beans and crotalaria are also used in the crop rotation as cleaning crops. Tree crops are introduced and are becoming increasingly important.

Repeated application of irrigation water and excess use of pesticides and fertilizers often cause salinization of the soil. In the spontaneous farming regions of Boqueirand Teixeira, farms are mobile and fields are abandoned after several years of cultivation. In the Petrolina-Juiro area, the fields are permanent and more intensively utilized. This is because the producers own the land and invest substantial capital in it. Crops are more carefully rotated and drainage ditches are often observed in the fields to remove accumulated salt.

Social and economic consequences are also substantial in the middle SFrancisco Valley. Irrigation farming and agro-industries have created a sharp increase in job opportunities in both field and factory. This has caused a rapid increase in the population of Petrolina and Juiro and their urban centres have grown rapidly. There are numerous seasonal workers who find work in the fields during the busy harvesting season. Manufacturers of irrigation equipment have also been attracted to the region. Brazil's two major manufacturers have branch offices here, and one company has built a factory to supply irrigation equipment for the entire North-East, as well as for largescale developments in the cerrado region. The twin cities of Petrolina and Juiro with the landscape and atmosphere of the frontier's boom towns, are the most important inland centres of the North-East.

Concentration of land has also taken place in the process of agricultural development in the middle SFrancisco Valley. Early public irrigation projects, such as Bebedouro and Mandacaru, aimed to settle small farmers by giving them titles to the land. However, CODEVASF's recent development policy appears to promote largescale industrial farms (see table 14.3). In addition, turnover of land ownership appears to be frequent. Developed parcelas in irrigation projects are sold and purchased, while large farms and undeveloped land covered with caatinga are also on the market. Thus, land ownership is easily concentrated in the Petrolina-Juiro area. The largest industrial farm owns 15,000 ha.

In the small-scale spontaneous developments of Boqueirand Teixeira, on the other hand, the traditional system of land tenure persists and increased concentration is less apparent. In Boqueirwhere irrigation farming is undertaken by renting land and ample uncleared caatinga still exists, purchasing land decreases mobility and productivity. In Teixeira, where half of the irrigation farms are tenant-operated, the area accessible to the reservoir water is already extensively used and landowners are not willing to sell their properties. Under these conditions, it is difficult to accumulate farmland. Besides, large-scale industrial farms appear to have little interest in these areas.

Our observations clearly suggest that irrigation farming has largely modified the traditional landscape and land use of the sert Has it, then, transformed fundamentally its traditional social and economic structure? Is irrigation agriculture a successful strategy for the economic development of the North-East? Is the new farming system ecologically and economically viable in the long run? Do these farming regions become development centres for the diffusion of the intensive cultivation system? We do not yet have complete answers to these questions. Continued observation of the changes currently taking place in the sert is required to this end.