The monotony of soybean monoculture dominates the landscape in many areas of Mato Grosso and other Brazilian states. The regularity of the rains in the Cerrado biome – Brazil’s savanna – favors this harvest at the beginning of the rainy season in September or October and enables a second planting of maize or cotton before the dry season. CREDIT: Mario Osava / IPSRÃ O DE JANEIRO, May 04 (IPS) – “Precipitation is fundamental; the streams and rivers we have would not be enough for irrigation even if they were the Amazon,” Dirceu said Deceming referring to the amount of water needed for the extensive crops in midwestern Brazil.
This continental-sized country has 12 percent of the world’s freshwater, but the droughts that exacerbated poverty in the semi-arid northeast and led to water rationing in a number of major cities over the past decade have shown that rainfall – partly through forest creates mangled ecosystems – is more important.
It’s not just a question of quantity, but also of timing: “Rain at the right time” is also the key to productivity, said Dezem, president of the Rural Land Owners Union in Tapurah, a municipality in the northern state of Mato Grosso.
Here, the largest national production of soybeans, corn and cotton is concentrated in Brazil, the world’s leading producer and exporter of soybeans.
Precipitation in this region is not decreasing, said the 64-year-old farmer, who immigrated from southern Brazil in 1986 and thrives where “there was nothing before”. The reports of a decrease in rainfall “are only guesswork by people unfamiliar with the situation,” he told IPS by phone from his hometown.
Dezem based his claim on the measurements he had been taking for more than 20 years, using a rain gauge which he admits to be not very precise, but with deviations of 1,600 to 1,800 millimeters per agricultural year (September to September ) with peaks of 1500 and 1500 shows 2500.
The situation is different, however, for the electricity sector, which is also largely dependent on precipitation as rivers provide two-thirds of the country’s electricity.
The water levels in hydropower reservoirs are low, particularly in two major Brazilian regions, the Midwest and the Southeast, due to lower rainfall across the country, warned the national electricity grid operator who controls the power generation sources.
Due to the scarcity of water, thermoelectric power plants that run on fossil fuels and generate greenhouse gases as well as more expensive electricity have to be activated.
Thanks to the rainwater collected and stored in tanks, Abel Manto has managed to grow vegetable and fruit trees in an orchard in the semi-arid ecoregion on his farm in the interior of the state of Bahia in northeastern Brazil. As there are no nearby streams, the farm’s year-round production depends on the use of rainwater. CREDIT: Mario Osava / IPS Some metropolitan areas are already experiencing difficulties with water supplies. São Paulo with 22 million inhabitants suffered from severe bottlenecks from 2014 to 2016, followed by Brasília (three million inhabitants) in 2017-2018 and Curitiba (3.7 million inhabitants), where rationing measures have been carried out since 2019 with no prospect of this Year.
“The intensity and frequency of the drought has increased in all regions of Brazil since the 2000s, with the exception of the south,” reported Ana Paula Cunha, researcher at the state’s National Center for Natural Disaster Monitoring and Alerting (Cemaden). based on a study done with 13 of her colleagues using data since 1961.
The southern region benefits from being closer to Antarctica due to the cold fronts that bring rain. The southern tip of Brazil as well as the north have year-round rainfall without the dry season of other regions, Cunha told IPS from São José dos Campos, where Cemaden is based.
“Atmospheric circulation is the main mechanism for the formation of precipitation in south-central Brazil. Cold fronts and the convergence zone in the South Atlantic produce precipitation in the summer,” added climatologist José Marengo, another Cemaden researcher.
This convergence zone leads clouds from the Amazon rainforest in the northwest to the southeast through the Midwest and thus ensures precipitation also for the large-scale agriculture of Mato Grosso, which mainly takes up part of the biome of the Cerrado savannah, which also benefits from the surrounding jungle in the North and southwest.
If this system stops working, precipitation can be reduced by up to half, as in the Pantanal (on the central-western border of Brazil), which has suffered terrible fires in the past two years.
“The dry season seems to be drier, hotter and longer, which delays the onset of rain and increases the risk of fire,” Marengo told IPS from São José dos Campos in the southeastern state of São Paulo.
“Forests in general, in addition to protecting the soil and rivers, are a source of moisture for rainfall in their region and the neighboring regions,” he emphasized.
The area with the highest soybean production in Brazil is highlighted in yellow next to corn and cotton in the biome of the Cerrado savannah in the center of the northern state of Mato Grosso. Regular rainfall between September and April and flat land favor the cultivation of soy by farmers who have immigrated from the south since the 1970s. The area produces 28 percent of the soy in Brazil, the world’s largest producer and exporter. MAP: Francisco Marcuzzo, Thiago Guimarães Faria and Murilo Raphael Dias CardosoThe Amazon forest recycles an enormous amount of water, generating three-quarters of the local rainfall and “transporting moisture, the so-called flying rivers, to the La Plata Basin” and south-central Brazil, stated he.
The Atlantic Forest, a wooded strip along the Brazilian coast that is hundreds of kilometers wide in some places, transports moisture from the ocean inland, particularly in the south and southeast where the forest is more extensive. In the northeast, the forests occupy few coastal areas and it is the trade winds that carry the ocean clouds inland.
“The destruction of the Atlantic Forest on the coast contributed to a warmer climate and less rainfall in the northeast,” said Cunha. Most of the region – 61 percent – has a semi-arid climate with rainfall between 200 and 800 millimeters per year.
The caatinga, the biome found exclusively in the semi-arid region with low, twisted vegetation and few leaves, has also been severely degraded, resulting in less rain and higher temperatures, said the researcher, a physicist with a PhD in meteorology.
She said it is important to take into account that higher temperatures worsen the water deficit by causing more water loss through evapotranspiration (evaporation plus plant transpiration). In other words, the drought intensifies with the heat.
“Removing the vegetation has no immediate effect on the climate, it takes time, it has a cumulative effect. But it does affect the climate and changing the climate affects the vegetation,” in a vicious circle that the “Changes in” explains local microclimate, “with growing differences between neighborhoods, as observed by locals, Cunha observed.
Silos and warehouses in the town of Lucas do Rio Verde, one of the soybean capitals in Mato Grosso, a state in northern Brazil, reflect the strength of local agriculture, which leads the country’s soybean, corn and cotton production. CREDIT: Mario Osava / IPS “Forests help maintain the water cycle, produce more rainfall and contain local temperatures. Coastal vegetation cover was a mechanism to maintain inland moisture flow, but has been thinned,” she complained.
This process can be seen in the differences between the rainy forests along the coast, where the original vegetation was preserved, and a transition zone with less rain and less lush forests before reaching the semi-arid “sertão”.
Environmental damage is reflected in the progression of desertification in some areas, but semi-arid conditions and eventual droughts are due to the circulation of the ocean atmosphere, which is influenced by both Atlantic and Pacific climatic phenomena such as El Niño and La Niña, Cunha said.
With mostly intermittent and few perennial rivers, rain is vital in the semi-arid northeast. Collecting rainwater in household tanks and otherwise has become a massive micro-infrastructure in rural areas, mitigating the damage from the longest drought in the region from 2012 to 2017.
In the soy growing region of Mato Grosso, rainfall is more of an economic factor.
“It varies a lot. It rains a lot one year, less the next, but the average stays the same. This year, for example, the rain was a little late. It was possible to plant on September 20th, but we met withheld until October, “said Dezem, the landowner.
The life cycle there follows the rains. From January 10th to February 25th, soybeans are harvested and maize is planted at the same time, since “90 days of moisture are required for a full harvest” and in April the amount of rainfall decreases before the dry season from May to August.
Timely rainfall and flat land, which are conducive to mechanization, form the basic requirements for large-scale production, which lured farmers from the south into today’s breadbasket in Brazil.
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