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Irrigation and drainage
Evolution of irrigation development
The irrigation potential of Brazil is estimated at 29.3 million ha (Table 7 and Table 8). This includes only areas where irrigation can be developed and excludes the areas of high ecological value in the North (Amazon and Tocantins basin). In the cerrado areas of the Centre-west, the potential for irrigation has expanded substantially in recent years, following recent advances in soil management and irrigation techniques applicable in that region.
Irrigation started in Brazil in the last century, in Rio Grande do Sul and in the semi-arid region of the Northeast. By the end of the 1960s, the Group for Integrated Studies on Irrigation and Agricultural Development (GEIDA) was created to enlarge the overall knowledge of the natural resources. It created various programmes such as the Pluri-annual Irrigation Programme (PPI) in 1969, and the National Integration Programme (PIN) in 1970. Many opportunities were given for private investments on irrigation and drainage: (i) the National Programme for Rational Use of Flood Plains (PROVARZEAS); (ii) the Programme to Finance Irrigation Equipment (PROFIR); (iii) the conception of “entrepreneurial lots” in public irrigation projects; and (iv) the implementation of the sub-sectoral Irrigation I project. In 1984 a new period started, characterized by the establishment of important programmes such as the Northeast Irrigation Programme (PROINE) and the National Irrigation Programme (PRONI), both in 1986. In that period, the role of the government was limited to the accomplishment of large works (transmission and distribution of electrical energy and macro-drainage) while the private entrepreneurs were in charge of the other investments. In 1995, the new government started preparing the national policy on irrigation and drainage.
In 2010 the area equipped for irrigation was estimated at 5.40 million ha (ANA, 2012), which represents 8 percent of the cultivated area. In 2006 it was estimated at 4.60 million ha, representing 7 percent of the cultivated area (ANA, 2009), and the area actually irrigated was estimated at 4.45 million ha (IBGE, 2006). In 1996, 1985 and 1975 the area equipped for irrigation was 3.12 million, 1.96 million and 1.09 million ha respectively, while it accounted for 0.46 million ha in 1960 (Table 9).
In 2006, Parana river basin accounts for by far the highest area equipped for irrigation, 1.41 million ha or 26 percent of the total area equipped for irrigation in Brazil. Northeast Atlantic (western part), Paraguay, Amazon and Paraniba basins account for the lowest irrigated area (Figure 2). Three states accounted for more than 50 percent of the total irrigated area in the country: Rio Grande do Sul (22 percent), São Paulo (17 percent) and Minas Gerais (12 percent). In Rio Grande do Sul, more than 80 percent of the irrigated area was used to grow rice under a flooding system. In contrast to what happens with other crops, the demand for water by irrigated rice is concentrated in a few months during the cultivating period. In the state of São Paulo, the irrigated area is utilized mostly for the cultivation of sugarcane, coffee, oranges and grains. In Minas Gerais the main irrigated crops are grains and coffee under centre-pivot irrigation (Government Office for Science, 2010).
Surface irrigation represents 49 percent of the total area equipped for irrigation, while sprinkler and localized irrigation techniques account for 45 percent and 6 percent respectively (Figure 3).
Irrigation techniques differ within Brazil. In the South, Southeast and Centre-west, rice as well as some vegetable and orchard crops are irrigated by simple flooding or using furrow irrigation. Water is diverted from numerous small streams and conveyed to the farm-gates through earth canals. This technology, together with proper land preparation and some mechanization, yields a good return. Modern irrigation technologies, which have a higher water use efficiency and require less labour, are preferred by large farmers in the cerrados for crops such as wheat, soybean, maize, and cotton, and by the producers of vegetables and fruits near the metropolitan areas in the Northeast. These technologies, which are increasingly used in private and public irrigation schemes, range from mobile sprinkler lines to state-of-the-art modern centre-pivot and other self-propelled irrigation equipment. In the Northeast there is a strong increase in the use of localized irrigation, due to the water scarcity in the area. Over the last decades, the area with surface irrigation has decreased and that with sprinkler irrigation for grain production and localized irrigation for fruit and vegetables has increased. Total water use efficiency is estimated, on average, at 40-65 percent for surface, 60-85 percent for sprinkler and 78-97 percent for localized irrigation methods.
Irrigated agriculture can be divided into public and private schemes:
- Public schemes (6 percent of the total irrigated area in 1996) are mostly in the northeast region (67 percent). The size of the irrigation schemes varies between 42 and 22 000 ha. Most of the investments are made by the government, which then allocates plots from 4 to 8 ha to poor or landless farmers (settlers). In addition there are some medium-size plots, from 8 to 32 ha, usually for professionals (agrarian technicians) and large-size plots, from 25 to 500 ha, for enterprises. Public irrigation systems depend on water supplies that have been developed using Government (usually Federal Government) funds. In 1998, the total cost of development of public irrigation projects in the northeast was approximately US$8 600/ha for surface irrigation, US$9 650/ha for sprinkler irrigation and US$10 150/ha for localized irrigation.
- Private schemes (94 percent in 1996) have been developed by private individuals or companies. Private development has received technical support from the Government especially under the PROVARZEAS programme and financial assistance through targeted credit lines. It comprises many forms of irrigation ranging from small-scale to large-scale, and from simple to highly sophisticated irrigation. In 1998, investment costs of private irrigation were considerably lower than in the public sector, ranging from US$1 600/ha for surface irrigation to US$2 650/ha for sprinkler irrigation and US$3 150/ha for micro-irrigation. Generally, investment costs of private irrigation are higher in the Northeast than in the other regions due to the difficulty for accessing perennial sources of water. Average costs of operation and maintenance range from US$ 35 to 95/ha. Costs can also be broken down into off-farm investment costs (water pumps, electrical support, conveyance, roads), that vary from US$4 500/ha to US$7 000/ha, and on-farm investment costs that vary from US$650/ha for simple surface irrigation methods to US$2 500/ha for localized irrigation.
Some important irrigation areas and schemes are (ANA, 2009):
- South Atlantic and Uruguay basins: great demand of irrigation by inundation (flooded rice)
- San Francisco basin: Verde Grande basin (irrigation projects); Polo de Barreiras in the city of Barreiras (irrigated soybean production); Juazeiro and Petrolina (irrigated horticulture)
- Araguaia-Tocantins basin: Project Formoso
- Alagoas: sugarcane zone
- State of Ceara: irrigation for horticulture
Role of irrigation in agricultural production, economy and society
In 2006, the area equipped for irrigation was 4.60 million ha, the area actually irrigated 4.45 million ha and the harvested irrigated crop area covered around 5.33 million ha, meaning an irrigated cropping intensity of 120 percent (Government Office for Science, 2010). Of the total harvested irrigated crop area, 32 percent consisted of sugarcane, 21 percent of rice, 12 percent of soybeans and 11 percent of maize (Figure 4 and Table 7).
In 1997, irrigation contributed an estimated 18 percent of total crop production in weight, and some 29 percent of total farmgate value (since irrigated crops are relatively high-value).
The range of crops grown under irrigation is diverse. In addition to basic commodities and to crops such as sugarcane and coffee, high-value crops are also grown whenever markets permit, like vegetables (some of them on a semi-industrial scale) near the important urban markets of the industrial Southeast. The same markets are supplied off-season with fruits, onions, melons and other vegetables from the Northeast. Expansion of tomato paste and other vegetable processing factories in the arid zones of the Northeast has created market opportunities for large-scale and small-scale irrigators, who increasingly export their fruit and off-season vegetables to Japan, Europe and the United States of America. Yields of crops vary widely throughout the country.
There has been a great diversity of performance between the public and private irrigation sectors. Public irrigation generally tended to progress slowly and fall short of performance expectations while private irrigation, especially in recent years, has expanded fast and often given high profits. However, direct comparisons are difficult due to regional differences in irrigation needs and opportunities, the special social needs of the impoverished Northeast and the different institutional arrangements for public and private development. In 1990 FAO, World Bank and the Government of Brazil undertook a detailed study to estimate the economic efficiency of Brazil’s irrigation. On the basis of information collected, eleven different models of irrigation farming were defined to represent irrigation in Brazil. The results showed that public schemes were systematically less economically efficient than private schemes and that basic commodities (cereals, cotton, beans, soybeans) would give a much lower return than fruits and vegetables. Under these conditions, the public schemes of the Northeast, growing staple food, yielded a very low return. Net economic benefit generated per 1 000m3 of water averaged around US$20 for low-value crops and US$50-400 for high-value crops, while net economic returns per year were, on average, around US$250 for low-value crops and US$2 000/ha for high-value crops.
Women and irrigation
Several studies carried out in Brazil conclude that women have a subordinated position in agricultural family work and it is considered in many cases as “help” even if they do the same work as men (Chiappe, 2005). The involvement of women in agriculture has been underestimated in statistics.
According to the Constitution of Brazil property rights or concessions under the agrarian reform program may be allocated to men and women either individually or as joint owners. Though, women are usually excluded from land inheritance practices, especially in rural areas and beneficiaries of agrarian reforms have been, largely, men. In the first census of the agrarian reform organized by the National Institute of Colonization and Agricultural Reform (INCRA) in 1996, after 32 years of agrarian reform, only 12 percent of women had land registered under their name. Access to water is in most cases depends on land tenure; as a result, women may find themselves disadvantaged to obtain water for irrigation. In general, women in rural areas have less access than men to resources, particularly to land and water.
In agriculture areas where water is often unavailable, it is usually women who must carry water home from wells or stream (Chiappe, 2005).
At present, the government of Brazil is developing policies to promote equal opportunities for men and women in the rural areas (Portal Brasil, 2015).
Status and evolution of drainage systems
Little information is available in drainage, salinity and waterlogging in Brazil. The surface with drainage equipment is around 1.28 million ha, mostly in the areas with irrigation equipment. Within the framework of the PROVARZEAS programme in the 1980s, around 400 000 ha were drained. Average costs of drainage development in 1996 range between US$1 600 and US$1 800 per ha for open drainage, and from US$2 300 to US$2 700 per ha for subsurface drainage.