Indispensable to life on Earth, the soil (pedosphere) is an element that influences and is influenced by the other main compartments of the Earth system, organisms (biosphere), water (hydrosphere), rocks and sediments (lithosphere) and the air (atmosphere), interacting with them in all the processes that determine quality of life in the Planet. Soil degradation and inadequate management have caused imbalance in water flows, in greenhouse gas emissions and in the attenuation of the effects of pollutants, directly influencing the regulation of water and air quality.  

It is no wonder that there is consensus in Academia regarding the need for technical-scientific advances for soil protection, with the aim of balancing several of its roles, such as production of food, fibers and fuels; nutrients and carbon storage; water filtration, purification and stocks; oxidation and reduction of organic and inorganic pollutants; and waste storage and degradation.

An important interference from the soils came to light with the recent Brazilian water crisis, which advanced beyond the borders of Northeastern backlands (where dry spells are a natural occurrence) and made it clear that the reasons for the lack of water go much beyond the scarcity of rains, and is closely related to soil management. Problems like erosion, compaction and impermeability not only reduce the amount of soil nutrients but also hinder water infiltration and filtration for the recharge of rivers and aquifers. As opposed to droughts, floods are also related to soils. A common problem in many Brazilian cities, the phenomenon especially occurs because water does not have where to infiltrate, especially due to the soils being covered with asphalt, flowing off to where there is less energy and accumulating at lower places.

Soils are also directly related to climate issues. Agricultural research is engaged in developing technological solutions that prevent soils from degrading from the standpoint of production capacity and that reduce greenhouse gas (GHG) emissions to the least possible, a process that is aggravated by the inadequate use of nitrogen fertilizers. In that sense, existing soil carbon has gained special attention. Besides preventing GHG emissions, research has sought to remove such gases from the atmosphere through agricultural activity, a process known as carbon sequestration, since the soil is one of the planet's main carbon reservoirs.

The Brazilian Government's Low Carbon Agriculture Program, which aims at reducing GHG emissions in agriculture through the adoption of sustainable technological solutions, was an advance towards the establishment of national knowledge bases on the subject. Through the survey and monitoring of areas with different management levels, it will be possible to more precisely learn the amount of carbon being sequestered from or being emitted into the atmosphere. It is known that the no-till farming system significantly contributes to carbon sequestration, as well as reforestation in areas without vegetation.

History of soil classification in Brazil

In-depth knowledge about soils and their roles is fundamental for their correct management and to map land suitability. The knowledge and identification of soil horizons and component layers and the improvement of the diagnostic criteria used in their identification are the result of the experience accumulated throughout the years in several countries. From the concept established by the Russian geographer Vasily Dokuchaev, it was possible to individually classify soils.

In Brazil, soil classification started at the end of the 19th century. But the first soil surveys systematically conducted in the domestic territory began in 1947, with the establishment of the Soils Commission of the Ministry of Agriculture's National Agricultural Research Service (SNPA). The efforts continued in the 1950s and 1960s, respectively, with the Brazilian Soil Recognition Survey Program, presented by the Commission, and with the foundation, in 1962, of the Division of Pedology and Soil Fertility, under the the National Department of Agricultural Research (DNPEA). In 1969, the Manual of Soil Analysis Methods was authored by Leandro Vettori, responsible for the beginning of the standardization of Brazilian soil analyses, currently on its third revised edition, which is used in laboratories throughout the country to date.

With the foundation of Embrapa, in 1973, the Division of Pedology and Soil Fertility was transformed, two years later, in the National Soil Survey and Conservation Service (SNLCS), current Embrapa Soils, giving continuity to the recognition work initiated in 1947. The information generated by the SNLCS provided the technical base for several applications, like the example of the reclaiming of the Brazilian Cerrados for agricultural production and the Ecological-Economic Zonings (EEZs) in many regions of the country. The accumulation of such knowledge, developed in partnership with universities and with the Brazilian Institute of Geography and Statistics (IBGE), ended up generating, in the 1970s, the Brazilian Soil Classification System, which in 1997 originated a book that is at its fifth edition - download the e-book here.

The conquest of the Cerrado

The Brazilian Cerrado is currently one of the largest agricultural frontiers of the world and an international reference in productivity. But it was not always like this. To reach its records in food production, it was necessary to correct the soils of the region, which are naturally acid and poor in nutrients.

Historically, agriculture in Brazil has always been developed in fertile soil regions, which would be cultivated to exhaustion and later abandoned. Hence the Cerrado region was seen as unsuitable to produce foods. But, in the mid-1970s, with the government's decision to expand agriculture to this region, it was necessary to especially invest in research to try to change such reality.

In this context, Embrapa Cerrados was established in 1975, and has led research related to determining indicators to evaluate the quality of soils in the region, both with regard to soil chemistry and with regard to their biology − which is especially connected to organic matter. With intensive field experimentation, throughout the last 40 years it has generated criteria to interpret soil analysis and adequately recommend fertilizers and correctives in suitable doses, which provided crops in the Cerrado with good productivity and economic returns. It is also worth noting the role of the discovery of biological nitrogen fixation, from the pioneering work of the researcher Johanna Döbereiner, initiated in the then Institute of Ecology and Agricultural Experimentation, currently Embrapa Agrobiology, which allowed Brazil to become the second world producer of soybeans, mostly sourced from the Cerrado region.

The challenges of agricultural research for this region are currently related to perfecting conservationist systems such as the no-till farming system, and the development of integrated production systems.

Megaproject will map Brazilian soils from North to South

There is still a large lack of data on the soils in Brazil, a country with continental proportions. Deeper knowledge about soils has great importance so that a nation can ensure their population's food security and sustainably-based development. Currently, the country only has general soil surveys, with small scale maps; less than 5% of the domestic territory has been mapped on a 1:100.000 scale or more detailed ones. That is a reality rather different from most developed countries, like the USA., for example, whose soil maps cover almost their entire territory on scales between 1:20.000 and 1:40.000.

To solve the problem of the lack of suitable knowledge about a good portion of the soils in the domestic territory, Brazil has just structured the National Soils Program (PronaSolos), the largest Brazilian technical-scientific enterprise in the area of soils. The mission is to map the soils of 8.2 million km ² of the national territory by 2048, in scales that vary from 1:25.000 to 1:100.000. Researchers and technicians from dozens of partner institutions will dedicate themselves to the investigation, documentation, inventory and interpretation of data on Brazilian soils. An investment on the order of R$ 4 billion in 30 years, with public and private funding. And an enormous return to society, which can reach 185 Reals for each Real invested in PronaSolos. 

The program, which involves dozens of partner institutions, will gather activities of investigation, documentation, inventory and interpretation of Brazilian soil data for the management and conservation of this resource. That information is fundamental for countless areas, ranging from climate changes and water resources to rural insurance and telecommunications, and will allow land use planning in Brazil, conjugating economic development in the field with the conservation of natural resources and the management of water resources.

The generated information will be systematized in a single database available for society, and will inform rural and urban public policy at national, state and city level. 

Visit PronaSolos' page and learn more about the program.