Agro: heat and drought reduce soybean productivity – 7/6/2023 – Market

Increased temperatures and droughts in the Brazilian cerrado reduce soybean productivity, concludes a study by Ipam (Amazon Environmental Research Institute), published in the specialized magazine International Journal of Agricultural Sustainability, in January of this year.

Scientists have calculated that every time the temperature in the cerrado rose 1°C above the historical average (1980 to 2018), soybean productivity fell by 6%.

“It doesn’t seem like much”, says Daniel Silva, who led the research at Ipam and is doing his doctorate at the University of Texas, in the United States. He says that the El Niño droughts in 2015 and 2016 raised temperatures above 3°C in areas of the cerrado, causing productivity losses of 18%, without analyzing factors such as soil management, irrigation, pests, etc.

For Silva, as El Niño returns in 2023, it could pose risks to soy.

Brazil currently produces 40% of the world’s soybeans, surpassing the United States (30%). More than half of the cultivated area in the country (57%) is covered by grain —the equivalent of 40 million soccer fields—according to the IBGE (Brazilian Institute of Geography and Statistics) and the USDA (United States Department of Agriculture).

As regions with favorable soils and climates become scarcer in the center-south of the country, soybean crops expand to hotter and drier areas of the cerrado, such as the region known as Matopiba (Maranhão, Tocantins, Piauí and Bahia).

Ongoing climate changes bring uncertainties to production, especially in soy expansion areas, according to specialists.

“It’s a shot in the foot [expandir a produção nessas áreas]”, says biologist Mercedes Bustamante, professor at UnB (University of Brasilia) and current president of Capes (Coordination for the Improvement of Higher Education Personnel).

The search from IPAM also showed that productivity began to drop when average annual temperatures exceeded 21°C, indicating that the northern portion of the cerrado could become unsuitable for agriculture, if climate projections are confirmed.

The INPE (National Institute for Space Research) estimated an average annual temperature increase of 2°C in Matopiba until 2046.

The latest report by the IPCC (Intergovernmental Panel on Climate Change) projected that temperatures in the central regions of Brazil will continue to rise above the global average, according to Bustamante, who was a member of the IPCC until 2022.

There is also a global trend of “dramatic increase” in droughts caused by global warming until 2100, impacting agricultural land, points out a North American survey of May this year, published in the prestigious scientific journal of the Nature group.

In Brazil, extreme droughts extended across almost the entire territory between 2011 and 2019, especially in the Northeast and Southeast, breaking 60-year records, according to a study by Cemaden/MCTI (National Center for Monitoring and Alerts of Natural Disasters), published in 2019.

Short-term climate change concerns more producers

Although scientific research demonstrates agricultural losses caused by climate change, farmers do not see the phenomenon as a significant threat and are more concerned with climate fluctuations in the short term, according to the Ipam survey, which interviewed 90 soy producers in Matopiba.

In total, the largest share (33%) considers that annual climate variation is the main barrier to increasing production. Then come access to credit (17%) and logistics (15%).

The majority (39%) said that changes occur by natural oscillations. Deforestation ranked third (13%) and global warming fifth (11%).

Deforestation makes the cerrado drier and hotter, showed research by UnB, published in 2022. According to the authors, exposed soils retain less moisture and affect the water cycle. A 10% reduction in water recycled to the atmosphere and an increase of 0.9°C in the average temperature in the biome was detected.

Another Brazilian study this year, conducted by researchers from the UnB in partnership with other universities, predicted a 34% reduction in the flow of rivers in the cerrado by 2050, “strongly affecting agriculture, electricity, biodiversity and water supply”.

For Ipam researchers, there is a belief that investments in capital and technology will circumvent climatic barriers, as occurred in the agricultural conquest in the cerrado. The acidic and infertile soils of the Cerrado did not prevent advances in adapted seeds and land interventions that raised soybean productivity in the region by 75% since 1980, says Daniel Silva.

Brazil has become a world food supplier, being the largest exporter of soy (56% of the total) and corn (28%) on the planet. Soy is exported in natura (76%), mainly to China (57%), according to Abiove (Brazilian Association of Vegetable Oil Industries) and USDA.

Daniel Silva and Mercedes Bustamante see no indications that the technology will respond to the rapidly changing climate underway, especially in vulnerable areas.

For Daniel, part of the farmers’ optimism is explained by the fact that they have occupied agricultural frontiers recently, making it difficult to perceive subtle climate changes that evolve slowly over decades.

Eduardo Delgado Assad, a professor at the Getulio Vargas Foundation (FGV/GVagro) and Unicamp (State University of Campinas), says that part of the soybean farmers have such high incomes that long-term climate impacts are secondary.

Brazilian soy has broken production records, even with billionaire losses from recent droughts. Production grew 11% in 2021, generating gains of BRL 340 billion, calculates the IBGE. The growth in GDP in the first quarter of 2023 was particularly due to soy.

Carlos Nobre, a researcher at the Institute of Advanced Studies at USP (University of São Paulo), also says that there is interference from ‘climate deniers’ campaigns against soybean farmers, which would be organized by associations of rural producers, and spread the myth that global warming by man does not exist.

Climatic shocks produce immediate effects on farmers, who react by changing the harvest calendar (29% of those interviewed), adopting a direct planting system (23%) and crop rotation (17%), found the Ipam survey.

The majority (83%) reported relying on loans to maintain their crops and that weather losses made new loans difficult.

The drama of indebtedness is followed by an increase in land concentration. Farms with more resources buy small properties that have succumbed to climate adversities, according to Ipam.

High temperatures also increase demand for water on crops, which requires more borrowing to cover irrigation costs.

For agronomist José Renato Bouças Farias, from Embrapa Soja (Brazilian Agricultural Research Corporation), water scarcity will be the main risk for the future of the grain. He calculates that the 2021/22 crop lost BRL 90 billion due to the lack of water in the states of Rio Grande do Sul, Paraná and Mato Grosso do Sul alone.

Half (49.8%) of the water collected in Brazil is used for irrigation. In the cerrado, irrigated areas jumped from 400,000 to 1.2 million hectares, according to ANA (National Water Agency) data from 2019.