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close this bookThe Fragile Tropics of Latin America. Sustainable Management of Changing Environments (UNU, 1995, 335 p.)
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close this folderPart 1 : The ecological outlook
close this folderEcological prospective for tropical Latin America
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View the document2 The current condition of the tropical Latin American ecosystems
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close this folderRich and poor ecosystems of Amazonia: an approach to management
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View the document2 Characterization of the oligotrophic environment
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close this folderArchaeological perspectives on the potential of Amazonia for intensive exploitation
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close this folderDistribution and interannual variability of rainfall in Brazil
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close this folderPart 2 : The Brazilian Amazon
close this folderWaters and wetlands of Brazilian Amazonia: an uncertain future
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View the documentSweet sea
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close this folderA fragile capitalism in a fragile environment: entrepreneurs and state bureaucracies in the free zone of Manaus
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close this folderPart 3 : The Peruvian Amazon
close this folderAquatic and land fauna management among the floodplain ribereños of the Peruvian Amazon
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close this folderSubsistence- and market-oriented agroforestry in the Peruvian Amazon
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close this folderLocal management of forest resources in a rural community in north-east Peru
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close this folderPart 4 : The semi-arid north-east
close this folderWhite sand soils in north-east Brazil
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close this folderChanging aspects of drought-deciduous vegetation in the semiarid region of north-east Brazil
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close this folderCharacteristics and utilization of tree species in the semi-arid woodland of north-east Brazil
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View the document2 Bioclimatic divisions of north-east Brazil and the floristic composition of the caatinga stand
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close this folderDrought, irrigation, and changes in the sertão of north-east Brazil
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View the document2 Reservoir irrigation in Paraíba
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2 Reservoir irrigation in Paraíba

Reservoirs in Para.

Reservoirs in Para. including those constructed by federal, state, and local governments, may be classified into three categories by size and type of use (table 14.1). A large reservoir has water storage capacity of over 200 million m, a medium-size reservoir ranges from 10 to 50 million m, and a smallscale reservoir holds less than 1 million m. Large reservoirs are constructed by damming up major rivers, while those of small to medium size are found around urban settlements. In addition, numerous small reservoirs of less than 1 million m of water are found in cattle fazendas.

The National Department of Works Against the Drought (Departamento Nacional de Obras Contra as Secas, DNOCS) is a federal organization for regional development of the North-East, which was established as early as the first decade of this century. DNOCS has constructed reservoirs intended as a development strategy against aridity and rural poverty. The intention is to augment agricultural production and to promote commercial agriculture in order to alleviate rural poverty and to stabilize the population in the semi-arid regions, which are characterized traditionally by extensive livestock grazing and subsistence farming (Hall, 1978).


Figure 14.1 Study area in Nortb-East Brazil. A: Boqueirarea; B. Teixeira area; C: Petrolina-Juiro area.

Up to the end of 1981, DNOCS had built 261 public dams and reservoirs in the North-East, with a total water storage capacity of 12.3 billion m. Among them, 38 are found in the state of Para, with a capacity of 2.5 billion m. In addition, 596 dams were constructed by DNOCS in the NorthEast for private water storage; their reservoir capacity amounted to 1.3 billion m. Para. has 59 such reservoirs (Ara1982). However, it has often been pointed out that these reservoirs are not necessarily utilized efficiently for local farming activities, despite the vast amount of water stored in them.

Boqueirreservoir and its vicinity

Boqueirmunico is situated on the eastern edge of the Paraiban sert in the middle Para valley. Here the caatinga vegetation predominates with jurema-preta (Mimosa hostilis Benth.), catingueira (Caesalpinia pyramidalis Tul.), and pereiro (Aspidosperma pyrifolium Mart.), as well as such xerophytic plants as facheiro (Cereus squamosus Guerke) and mandacaru (Cereus jamacaru DC). Although annual precipitation fluctuates substantially, the region receives 400 to 600 mm in an average year. The rainy season is from March through August.

The Para River was dammed up by DNOCS in 1956. Boqueirreservoir, with a water capacity of over 500 million m, belongs to the largescale category. It is variously utilized for urban consumption, electric power generation, irrigation, fishery, recreation, and flood control.

Boqueirs economy has depended traditionally on livestock grazing and rainfed cultivation of maize, beans, cotton, and palma, a cactaceous plant used for cattle feed. Cattle are the most important animals, grazed in the caatinga as well as in the stubble of crops. Beans, maize, and cotton are cropped together for three to four years after the scrub is cleared. Palma and xerophytic plants become increasingly important as fodder for cattle during the dry season. Absentee landlords are not numerous. The landholding pattern of Boqueirshows the transitional characteristics from the agreste to the sert.

Although irrigation farming was primarily undertaken on the floodplain to grow elephant grass, a type of sorghum used for cattle feed, it gradually expanded to the interfluvial areas using water pumped from the reservoir and the Para River. Irrigated acreage increased substantially in the late 1970s, when tomatoes, bell peppers, and bananas became particularly important. In 1980, the area under irrigation amounted to around 400 hectares. Boqueirreservoir, blessed with an ample quantity of water, is able to provide water for farming all the year round, and the area under irrigation is expanding.

During our field study in this area in October 1988, we identified 31 irrigation fields operated by 26 farmers (fig. 14.2). These fields are situated within two kilometres' distance from either the reservoir or the Para, River. The total area under irrigation, crop production, and the type of irrigation were investigated. We also interviewed fourteen farm households regarding land tenure, family structure, residence, previous occupation, and crop marketing methods. Landuse surveys were also conducted. Figure 14.3 shows an example of an irrigation farm on the left bank of the Para. River. In this farm, operated by a tenant farmer, tomatoes were first cultivated after clearing of the caatinga. Watermelons followed tomatoes. Then the field appears to have been rotated to either cotton or maize and beans (feij, and eventually returned to caatinga. The details of the study are elaborated elsewhere (Saito and Yagasaki, 1989).

Table 14.1 Classification of reservoirs in Para, North-East Brazil

Size Name of reservoir Construction Storage
Capacity
('000 m)
Year Agency
Large Coremas 1942 DNOCS 720,000
Mae D'Agua 1956 DNOCS 638,000
Boqueir/td> 1956 DNOCS 536,000
Engenheiro Avidos 1936 DNOCS 255,000
Medium SGono 1936 DNOCS 44,600
Sume 1962 DNOCS 36,800
Eng. Arco Verde 1936 DNOCS 35,000
Soledade 1933 DNOCS 27,058
Jatoba I 1954 DNOCS 17,520
Santa Luzia 1933 DNOCS 11,960
Taperoa 198? Canatd> ?
Small Lagoa de Meio 1955 DNOCS 6,648
Riacho de S. Antonio 1956 DNOCS 6,834
Serra Branca 1966 DNOCS 2,117
Po 1923/53 DNOCS 2,000
Bodocongo 1915 DNOCS 1,020
SFrancisco 1984 Canaup>a 9,000
Communal aes 1930~ Community  
Aes in Fazendas 1950~ Individual
Roadside aes 1970~ Community

Source: Based on Ara1982): Darns in the northeast of Brazil, DNOCS, and field observa tion.
a.Governmental project of Para.

While the produce is sold locally at the periodic market known as the feira, most crops are shipped to the public wholesale produce markets (CEASA) of large cities in Para. and Pernambuco. Boqueirao's tomatoes and bell peppers are particularly important at the wholesale market of Recife,
where they represented 12.3 per cent and 13.2 per cent respectively of the total receipt in 1987.

Table. Use of reservoirs

Use of reservoirs

Hydroelectric Irrigation Urban Individual Animal Fishing Recreation Flood

Control

Gravity Pump
O O   O   O O O O
O   O O   O     O
O O O O   O O O O
          O      
O O   O   O O O  
      O   O O    
  O       O      
          O O    
  O   O   O O   O
    O O          
      O     O   O
      O          
      O   O O    
      O   O O    
    O O   O      
      O          
    O     O      
      O O O      
        O O      
        O O O    

Irrigation farms are mobile and transient, easily shifting from one location to another. The repeated use of land causes plant diseases and declining productivity. Simple irrigation equipment and the acquisition of land by tenancy facilitate such mobility. In the fields, crops are typically rotated. After the land is rented, the caatinga cover is cleared and burned, the field is prepared, the irrigation ditch is dug, and water is secured by installing electric pumps and water pipes.

Tomatoes are generally grown for the first one to two years. The field is then planted in bell peppers, and afterwards rotated to cotton. Cotton fields eventually turn to banana fields before being abandoned and returning to caatinga. The crop rotation systems are summarized in table 14.2.

Although the production and marketing of irrigated crops have so far been successful, it is rather doubtful whether spontaneous irrigation farming has expanded employment opportunities in Boqueir


Figure 14.2 Irrigation farms around BoqueirReservoir, Para. (Based on interviews.)

Teixeira plateau

The Teixeira plateau is located in the heart of the Paraiban sert some 270 km inland from JoPessoa and overlooking the Patos basin. Due to its high elevation, ranging from 750 to 900 m above sea level, the region has relatively mild climatic conditions with rather stable precipitation. February through April is the main rainy season, when 80 per cent of the annual precipitation is received. The environment, resembling that of the brejos typically found in eastern Para is rather favourable for farming activities.

Teixeira munico is dominated by small landholdings. Cattle and goats are the main animals, but the role of livestock in the economy of Teixeira is limited (Saito and Maroyama, 1988). Maize and beans are important food crops, while sisal and cashew nuts constitute the major cash crops.


Figure 14.3 Land use of an irrigation farm on the Para River. 1: tomatoes; 2: tomatoes harvested; 3; watermelons; 4: bell peppers; S: cotton; 6: maize and beans; 7: wasteland; 8: caatinga; 9: uncultivated land; 10: corral; 11: irrigation pipes; 12: fences; 13: aveledgerow; 14: simple hut; 15: residence; 16: road. (Based on field observation.)

Although the local residents attempted to construct a small reservoir in the late nineteenth century by damming up a small stream of the Po River, the present Po Reservoir was completed by DNOCS (then called IFOCS) in 1923. Reconstructed thirty years later, the reservoir now holds 2 million m of water. However, the reservoir alone did not promote the development of irrigation farming. The real growth took place after 1984, when the SFrancisco reservoir was built on the Po River upstream of the Po reservoir as part of the state-sponsored Cana project. This reservoir, with a capacity of 9 million m, effectively promoted irrigated farming. In 1987, a third reservoir, named So, was constructed downstream on the same river. Although these three reservoirs belong to the smallscale group in our overall classification of Para's reservoirs, they have played important roles in intensifying Teixeira's farming.

Table 14.2 Land use cycles in the sert North-East Brazil

Irrigation method Location

Years

Land use cycle (yrs) Use of caatinga Reference
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
No irrigation (rain) Caatinga/sert/td> D Caatinga(r) 30 Charcoal/ fire- wood/fence Johnson (1971)
Caatinga/Boa D Caatinga(r) DCaatinga(r) 10
Ventura MF MF Caatinga(r) DMF 15
Field/sertao MF MFA A A Caatinga(r) DMF 15 Fence/char- coal Andrade (1968)
Field/Boqueir/td> MF MFP P P P Caatinga(r) DMF 15
River Flood Vea (flood- plain) MF(r) 1 - Andrade (1968)
B(r) 1 _
R(r) 1 -
Ae and river Pump Boqueir/td> TT TT A A Banana(r) ? - Field Observation
Pump Boqueir/td> PP PP PP PP MF MF Orange(r) ? -
Pump Teixeira TT TT TT CC CC CC CC CC Caatinga(r) ? Ash
Pump Petrolina F F Grapes(r) ? -
Canal Petrolina TT TT TT F F F Tree crops ? -
Canal Petrolina TT TT F F F MF MF MF TT TT F F F MF MF 8 -
Canal Petrolina N N F F F MF MF MF N N F F F MF MF 8 -
Ground water (pumpwell)   Mossorio Grande doNorte) N Capoeira(r) DNCapoeira(r) DN Capoeira(r) 5 Ash Interview

D: clearing of caatinga; Capoeira: second growth; A: cotton; P: palma; M: maize; F: beans; B: sweet potatoes; R: rice; N: melons; T: tomatoes; P: bell peppers; C: carrots;
(r)continuous land use.


Figure 14.4 Distribution of irrigation farms in Teixeira, Para. (Based on interviews and data from the Bank of Brazil.)

In our field research, 88 farms utilizing irrigation were identified in the Texeira munico, based on our interviews and the data supplied at the branch office of Bank of Brazil (for details see Yagasaki et al., 1989). The total irrigated area amounted to 261 ha. This figure is nearly six times larger than that enumerated in the 1980 Census of Agriculture. Most irrigated fields are found around the Po and SFrancisco reservoirs, while others are dispersed, utilizing water from smaller reservoirs or rivers (fig. 14.4).

Carrots, tomatoes, and table beets are the major irrigated crops, accounting for 74 per cent, 16 per cent, and 5 per cent, respectively, of the total irrigated areas. Carrots are the most important, and are grown twice a year on wide mounds called canteiros with plenty of water and care. Figure 14.5 shows the land use of an irrigation farm on the SFrancisco reservoir, with carrots and tomatoes being the major crops. The owner plans to continue planting carrots for the next fifteen years. After tomato is harvested, the field will be planted with bell pepper and onions.

There are three types of irrigation farms, operated by ownergrowers (proprietos), renters (arrendatos), and share-croppers (meieros). Since it is difficult to purchase farmland within easy access to the reservoirs, renters and share-croppers are becoming increasingly dominant. They constitute one-half both in terms of acreage and the number of farms. Most of these farms have taken advantage of agricultural loans from the Bank of Brazil. Such agricultural credit can cover from 70 per cent to nearly 100 per cent of the necessary investments.


Figure 14.5 Land use of an irrigation farm in Teixeira, Para. 1: farm shed; 2: irrigation pipes; 3: carrots; 4: caatinga; 5: tomatoes; 6: other land use; 7: wasteland; 8: SFrancisco reservoir, 9: road. (Based on field observation.)

Carrots and tomatoes are marketed to the CEASAs in the major cities of the North-East. Carrots are particularly important in Fortaleza, Recife, and Salvador. In 1987, Fortaleza received some 2,000 tons of carrots from Teixeira, amounting to 34 per cent of the total receipt. In Recife, Teixeira's carrots accounted for 11 per cent. Teixeira is considered one of the major carrot-producing areas in the North-East. This development took place in a relatively short period of time.