Irrigation in Brazil has been developed through the use of different models. Public involvement in irrigation is relatively new while private investment has traditionally been responsible for irrigation development. Private irrigation predominates in the populated South, Southeast, and Center-West regions with most of the country’s agricultural and industrial development. In the Northeast region, investments made by the public sector seek to stimulate regional development in an area prone to droughts and with serious social problems. These different approaches have resulted in diverse outcomes. Of the 120 million hectares (ha) that are potentially available for agriculture, only about 3.5 million ha are under irrigation, although estimates show that 29 million ha are suitable for this practice.
Development
Infrastructure and linkages with water resources
Although irrigation methods in Brazil may be considered modern compared to those of other countries in the region, gravity irrigation accounts for 48% of the total irrigated agricultural area (3.5 million ha), 42% use flooding (rice), and 6% use furrows or other gravity methods. Of the remaining 52%, approximately 22% use mobile sprinkler systems, 23% use mechanized sprinkling (central pivot), 1% uses perforated or gated tubes, and 6% use localized irrigation, i.e., drip and/or micro-sprinkling systems. Brazil has always been considered a country rich in water. However, Brazil's hydro-climatic regions and irrigation systems vary widely. In the South, frosty conditions in winter have limited irrigation mainly to summer flooding of lowlands for rice production. In the milder Southeast, irrigation in winter has made double-cropping possible. Winter wheat, peas, or beans are rotated with rainfed summer crops, including cotton. Local water shortage occurs in some small watersheds in the Southeast and South where irrigation development and water consumption for industry and municipal use have been relatively uncontrolled. The large size and level terrain of farms in the vast cerrado areas of the Center-West are well suited to center-pivot and self-propelled irrigation systems, which have expanded rapidly in the last few years. Much of the Northeast is semi-arid land and has severely limited water resources compared with the other regions. Most irrigation projects depend upon the few perennial rivers such as the Sao Francisco. The groundwater supply is limited so approximately 95% of irrigated lands use surface water. Water from the Sao Francisco River, the main river in the Northeast, has to be conveyed over considerable distances to irrigable land . Most of Brazil's humid tropics are in the North. Irrigation needs in that region are low, and development is limited to small areas of lowland rice.
Environmental impacts Little information is available on drainage, salinity, and waterlogging in Brazil. The natural saline areas in Brazil are quantified on average at 86 million ha, located especially in the driest areas with average precipitation below 1,000 mm/y. The area affected by salinity as a result of improper irrigation is estimated at 15,000 ha and is located mostly in the Northeast, affecting 40% of the irrigated land. The extension of the areas with natural waterlogging, called "varzeas", is 13.35 million ha.
History
Agricultural land In 1970 there were fewer than 800,000 hectares (ha) of irrigated land, used mainly as rice paddies in the state of Rio Grande do Sul, and less intensively in some public irrigation areas in the Northeast. Irrigation has really only taken off since then, with the implementation of public investment policies in infrastructure for irrigation, energy transmission and distribution, and finance for equipment and day-to-day expenses through programs such as the Northeast Irrigation Program (PROINE) and the National Irrigation Program (PRONI). Today about 3.5 million ha are under irrigation, although 29 million ha are estimated to be suitable for irrigation by the National Water Agency (ANA). Irrigation is developing through different models. In the South, Southeast, and Center-West regions, private irrigation predominates. with emphasis on planting rice and grain crops. In these areas investment depends on the return obtained from the sale of the irrigated crops. Investment in the Northeast has traditionally been focused on crops such as corn or beans, and has moved to irrigated fruit production.
… excerpt ends here. Continue reading the full article.
