Project analyzes nutrient loss through erosion in sugarcane and soybean areas

A study linked to the Paraná Network of AgroResearch and Applied Training (Rede AgroParaná) monitors and evaluates the amount of macronutrients and sediment transported by erosion in areas cultivated with sugar cane and soybeans, under different managements. Conducted by the University of Maringá (Unicesumar), the project has been carried out since August 2020, in the Arenito region, more specifically in the municipalities of Cianorte and Presidente Castelo Branco, in the Northwest of Paraná. The AgroParaná Network is a partnership between SENAR-PR, Fundação Araucária and the State Secretariat for Science and Technology.

In both municipalities, two megaplots – areas of two hectares – were installed, one with terraces and the other without terracing. In Castelo Branco, researchers maintain sugarcane cultivation; in Cianorte, soybeans, in rotation with corn and oats. The megaplots are equipped with monitoring and collection structures for rainwater runoff. After rainfall, the material captured in the field is analyzed in the laboratory by researchers.

“Whenever rain occurs or is forecast, technical assistants go to the field, regardless of the time of day or day of the week. We have equipment that captures and records the volume of runoff. Samples are collected in vials and in the laboratory this is processed. Then, we analyzed the amount of sediments and water. With this, we know how much nutrients came out, how much water drained and how much infiltrated the soil”, explains the project coordinator and professor at Unicesumar, Edison Schmidt Filho.

These analyzes compare the amounts of phosphorus obtained from the soil samples collected. The researchers then correlate the results with the volume of precipitation, generating information that makes it possible to quantify the macronutrients that existed in the soil before and after each rain and the amount transported in the erosion process. Preliminary data indicate that areas cultivated with terracing have suffered less erosion and nutrient losses, indicating the efficiency of conservation practices.

In the Cianorte megaplot, for example, there are indications that in the rain analyzed on April 12th there was a runoff of 25.705 mg/l of sediment in the area without terrace and 800 mg/l in the area with terraces. In the case of phosphorus, there was the presence of 0,1897 mg/l in the schooled water of the megaplot without terracing and 0,0047 mg/l in the cultivated strip with terraces.

“Understanding and quantifying macronutrient losses due to chemical erosion and siltation are fundamental points for defining the management and conservation practices that should be recommended for each type of soil in the State. The project was created precisely so that producers have an alternative to improve their soil management through better conservation structures and planting techniques that prevent erosion and contamination of watersheds. This is essential for the producer, who will have more efficiency in their production, and also for the city, which will have its basin preserved”, observes Schmidt.