UF/IFAS RCREC Graduate Student Highlight: Leandro Otavio Vieira Filho

By: Bethany Wight, Biologist
UF/IFAS Range Cattle Research and Education Center

Leandro with poster at UF/IFAS RCREC Field Day.

Leandro Otavio Vieira Filho grew up on his parents’ ranch in the small town of Sao Jose dos Ausentes in the most southern Brazilian state, Rio Grande do Sul. His family owns a seventh generation beef cattle ranch that is approximately 4,000 acres. Growing up he enjoyed being outside in nature and riding his horses. One of his fondest memories was going to rodeo events with his brother which also led him to start competing in roping events at a young age.

“Growing up I was lucky to have such a safe outdoor space to play. A lot of other parts of Brazil are dangerous but I was able to grow up playing outside and enjoying nature safely.”

Leandro and his horse rounding up cattle at Tapes Ranch in Sao Jose dos Ausentes, Brazil.

Leandro attended the Federal Institute of Santa Catarina in Santa Rosa do Sul, Brazil and graduated with a Bachelor’s in Agronomy in 2016. During his undergraduate studies, he completed an exchange program at Oregon State University from September 2013 – December 2014. He began by studying English and taking a couple classes and then spent the summer at the Eastern Oregon Agricultural Research Center. During his time at the research center, he was involved in a project that was focused on evaluating a seed coating technique that favored water retention and seed germination. He also worked on a project related to water stress and the use of this new seed coating technique on white cabbage and hybrid onion crop.

Shortly after graduating, Leandro started his Master’s degree at the University of Sao Paulo under the guidance of Dr. Francisco A. Monteiro. His master’s research examined the use of silicon on Tanzania guinea grass as a phytoremediator of copper under different management strategies. Results from his master project indicated that silicon improved guinea grass’s ability to tolerate high soil copper levels, as most of the copper accumulated in the roots allowing the adequate growth of above-ground biomass. He completed his Master’s degree in Soil and Pant Nutrition in 2018.

After earning his master’s degree, Leandro moved back to work on his family’s ranch where he was involved in all aspects of the beef cattle operation, including checking cows, managing pastures, conducting vaccinations, building and fixing fences, shooing horses, and feeding cattle.

“The main reason I came back to work on my family ranch was because I had decided to apply for a PhD position and I needed time to prepare for the GRE and TOEFL exams and other related applications. It was hard to do, as I worked during the day and studied at night. I had to use my time very efficiently, there was no time to procrastinate.”

Leandro collecting soil moisture data from a datalogger in the biosolids field experiment at the Range Cattle REC in Ona, FL
Leandro and Dr. Silveira collecting soils under different biosolids management from a ranch in Indian River County, FL

Leandro had heard about Dr. Maria Silveira’s work during his bachelor’s degree and began getting more interested in soil’s research. While studying at University of Sao Paulo, he had worked mostly with plants and he wanted to expand his education by researching soil chemistry and fertility. After being admitted to the UF/Soil and Water Sciences Department graduate program, Leandro began his PhD in the summer of 2019.

Leandro’s doctoral research focuses on agronomic and environmental aspects of soil P management in Florida grazing land ecosystems. His research project addresses concerns relative to the new proposed restrictions on land application of biosolids in Florida. Leandro’s research aims to demonstrate the multiple benefits of biosolids recycling programs, including less environmental risks than commercial fertilizer or other biosolids disposal options such as land fill. He is in the first year of his PhD program and is currently working on the research questions and experimental approaches he will be using in his research project. One component of his project consisted of a fully-instrumented field study equipped with soil moisture probes and lysimeters to evaluate water quality. This project has been funded by the Florida Cattle Enhancement Board and is currently in its 4th year.Leandro has been monitoring water quality parameters before the treatments are imposed so he can determine the impacts of his treatments compared to baseline values. He will continue to collect water samples (weekly, bi-weekly, or after major rainfall events) during the next 2 years.

Soil incubation study with soils subjected to different moisture regimens and biosolids application history.

Other components of his research project are also underway. The first part is a soil incubation study to examine P dynamics in soils subjected to different biosolids application histories. Treatments include a control (no biosolids), low biosolids load, and high biosolids load. In addition, they also evaluated the impacts of additional biosolid applications on soil P dynamics. In theory, there should be more P in soils that had previous biosolid application, however iron and aluminum added with biosolids can also promote soil P absorption, so this project will address important questions relative to the role of biosolids and moisture regimen on soil P availability.

Another ongoing study consisted of a greenhouse trial that examines how water table levels affect P leaching. Soil samples were collected from the same commercial cow-calf ranch and treatments included a control, low and high biosolids application levels. Water table levels were maintained at the top of the B horizon or the entire soil column was flooded. Columns were drained bi-weekly to determine how much P leached from the soil.

Leandro refilling columns of soil profiles to evaluate P leaching in soils under different biosolids management at the Range Cattle REC in Ona, FL.

Lastly, Leandro’s project is focused on developing a state-level P budget. Using government data and a state-wide survey, Leandro and his team will be able to calculate the contribution of the beef cattle industry to the overall P budget in Florida. They expect this effort will generate science-based information that will help educate the public about the importance of the beef cattle industry in the state.

When Leandro is not conducting his research, he enjoys exercising and traveling. He is planing to complete his PhD program by the end of 2022 or beginning of 2023. After graduation, Leandro will look for a postdoc or professor position here in the US or in Brazil.

“I hope to become a professor and I would be especially satisfied if I could work in a research station like the one I work now. I am also open to a position in the industry as long as it is in the fields of soil chemistry, nutrient management and/or plant nutrition.“

Leandro participating in a rodeo in his hometown in southern Brazil. This sport is called “long rope” due to the size of the rope used.


Bethany Wight

This was written by Bethany Wight, a biological scientist at the UF/IFAS Range Cattle REC in Ona, FL. If you have questions please contact her at bwight@ufl.edu.



Andrea Dunlap, Educational Media/Communication Coordinator at the UF/IFAS Range Cattle Research and Education Center (RCREC)
Posted: July 10, 2020

Category: Agriculture, UF/IFAS Research, UF/IFAS Teaching
Tags: Leandro Otavio Vieira Filho, Maria Silveira

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