Soil analysis assesses the impact of floods in RS

A year ago, researchers from the Department of Agricultural Research and Diagnosis of the Secretariat of Agriculture, Livestock, Sustainable Production and Irrigation (DDPA/Seapi), Emater/RS, the Soil Department of the Federal University of Rio Grande do Sul (UFRGS) and the Brazilian Agricultural Research Corporation (Embrapa Trigo) — who appear in the images that illustrate this article — would not be visible if they were in the same place. This is because, in the same period in 2024, the waters and debris from the worst flood in the history of Rio Grande do Sul submerged the municipalities of Estrela and Lajeado, in the Taquari Valley.

On Thursday (12/6), the scenario was different, although the agenda was related to the floods. The researchers visited rural properties in Estrela and Lajeado that were hit by the floods, with the aim of mapping and analyzing the water infiltration capacity of the soil. The activity began in Estrela, where representatives of the institutions involved and local leaders met to align actions.

On one of the first properties visited, the water reached a height of over four meters. Standing in the middle of the destroyed crop at the time, farmer Fernando Malmann recalls the force of the tragedy, pointing to an electricity pole. “I’ll show you on the pole. There, on that telephone wire, in relation to where we are now, the current reached a height of four meters and swept everything away. This place turned into a river,” says the farmer from Estrela.

More than a one-off diagnosis, the initiative aims to promote dialogue between government, research institutions and rural producers. Water infiltration tests in the soil are performed using an infiltrometer — a device that measures the rate of water penetration — and are essential for assessing the natural drainage capacity of the affected areas.

Researcher Altamir Mateus Bertollo, from DDPA, highlights the innovative nature of the methodology adopted, which eliminates manual calculations and provides accurate data to guide producers and support public policies. “This is a partnership between institutions, which began in Estrela — a region severely affected by the flood — and will be expanded to other areas of the state. The objective is to diagnose the conditions of water infiltration into the soil and offer technical support for the management practices adopted by producers. In this specific area, the work will be monitored for at least two years, covering different levels of soil preparation.”

For researcher André Amaral, from Embrapa Trigo, mapping soil porosity, measuring its infiltration capacity and building a database help in the adoption of good management practices, especially in the context of the Direct Planting System. “The greater the infiltration capacity, the better the soil quality and the greater its ability to retain nutrients,” he emphasizes.

According to Professor Michael Mazurana, from UFRGS, a specialist in agricultural mechanization and soil-machine relationships, the diagnosis is essential to understanding the reality of the soil. “The proposal includes the identification of agricultural areas that will act as technical reference units for training producers and technicians, with the aim of making them agents for the dissemination of agricultural practices aimed at recovering the productive environment, reestablishing the productive and investment capacity of the agricultural sector,” he says.

Partnerships and integrated actions

Using resources from the Recupera Rural RS program, Seapi acquired 10 infiltrometers and Embrapa acquired five more. With the support of UFRGS and Emater/RS, the initiative aims to carry out measurements in different cultivation systems throughout the state, with the objective of evaluating the water infiltration capacity of the soil. Soils managed in a way that favors greater infiltration contribute to the reduction of surface runoff, the main cause of flooding, and can also store water to supply plants in drought situations.

The coordination between the institutions has made it possible to expand the database and deepen the diagnoses. The infiltration tests are conducted in different layers of the soil — both surface and subsurface — on properties monitored by technicians and researchers from the entities involved.