Irrigated crop areas grow 3.8 times in 37 years
Three out of every four hectares irrigated by central pivots are soybean crops followed by second-crop corn
The mapping by satellite images of crops irrigated by pivots, flooding and other irrigation systems shows that these areas almost quadrupled between 1985 and 2021, from 804,000 hectares in 1985 to 3.29 million hectares in 2021. The data also show a change in the type of irrigation most used. In 1985, about 84% of the irrigated area mapped in Brazil was flooded. In 2021, this percentage had fallen to 44%. The area irrigated by central pivot, in turn, went from 8% in 1985 to 50% in 2021. As flooding is basically used in rice cultivation, the advance of pivots suggests the expansion of irrigation to other crops, notably soy: 76% of the pivot areas are planted with this legume.
The mapping of irrigation systems by satellite images is complex and the available technologies do not yet allow the identification of all irrigated areas in Brazil. For this reason, MapBiomas focuses on systems that are also mapped by other institutions, such as the National Agency for Water and Basic Sanitation (ANA), to benchmark the results. The more conservative approach does not reduce the breadth of the mapping, which was able to identify irrigated crops in the South, Southeast, Center-West and Northeast regions of Brazil.
"The data leave no doubt that many producers have embraced crop irrigation as a solution to ensure water security during cultivation," explains Bernardo Rudorff, Mapbiomas' irrigation mapping coordinator. "They also indicate that adhesion was greater by producers in the Cerrado, a biome that has a shorter rainfall cycle in certain regions for the cultivation of more than one crop," he points out.
Together, the states of Minas Gerais, Goiás and Bahia account for almost two thirds (64%) of the area mapped by central pivot irrigation in Brazil. One third of the total (31%) is in Minas Gerais, the state with the largest irrigated area over the 37 years evaluated by MapBiomas. In 2021, the irrigated area in Minas was 509,133 thousand hectares, equivalent to three times the city of São Paulo.
The five states in Brazil that presented the largest expansions of central pivot irrigation area between 1985 and 2021 were Maranhão, Goiás, Distrito Federal, Bahia and Mato Grosso. The last four presented an expansion between 51 and 53 times in 37 years. In the case of Maranhão, however, the expansion was 286 times - a clear reflection of the agrarian expansion in Matopiba.
MapBiomas identified 26 large pivot irrigation regions in the country, the largest of which is in western Bahia: about 180,000 hectares, a 14.5-fold increase over the area mapped in 1985.
Other irrigation systems were mapped only in the Brazilian semi-arid region. In this region, the Petrolina / Juazeiro pole presented the largest area in 2021, with about 70,000 hectares - a 4.5-fold increase in 37 years.
Flood irrigation is used prevalently in rice, and the largest poles with flooded rice are in the south of the country. In this region, the Quaraí / Ibicuí / Icamaquã pole in Rio Grande do Sul had the largest area, with more than 450,000 hectares - a 2-fold increase between 1985 and 2021. Outside the southern region, the Javaés / Formoso Complex, in the state of Tocantins, was the one that presented the largest growth in irrigated rice area: about 1.7 times in 37 years, reaching an area of 100 thousand hectares in 2021.