Strengthening farms for tomorrow’s challenges
Contributed by: S. Carolina Córdova (she/her)
Keywords
Agriculture, Agroecosystem, Carbon, Climate change, Environmental change, Field, Hispanic, Lab, Nationality, North America, Race/ethnicity, Societal relevance, Soil ecology, Woman
Slides
Note: click the gear symbol to see notes that accompany the presentation.
View and download in google slides here.
Resources
Check out the Data Nugget activity about this research:
Notes
Slide 1: Researcher’s Background
Researcher’s Background
Caro Córdova is a soil scientist and trained agroecologist at the University of Nebraska-Lincoln. Her research emphasizes carbon sequestration, nitrogen fixation, and long-term resilience in diverse cropping systems, contributing to advancing regenerative agriculture globally.
Why did you become a biologist?
The passion I have for soils comes from my dad, a civil engineer. Since I was a child, I’ve been involved in lab analyses and field studies, learning how to work with soil. Over time, my interest shifted from the engineering side of soil to its role in science and environmental protection. Now, my focus is on using soil science to safeguard the environment and support communities by building and maintaining healthy soils.
What is your favorite part about your job?
My favorite part of my job is working with multidisciplinary teams, where experts from different fields come together to solve big, complex problems. I learn so much from collaborating with these teams, and together we can tackle challenges that no single discipline could address alone. Another aspect I deeply enjoy is sharing my passion for soil science with future generations through mentoring, advising, and teaching. Helping students discover the importance of soil and inspiring them to pursue careers in science is incredibly rewarding.
What obstacles have you overcome to get where you are?
As a graduate student, I took a crop physiology class despite knowing the professor had a reputation for racist behavior, though he was highly regarded in the field. During a lecture near Easter, he made an offensive comment stereotyping Hispanic students as lazy, suggesting we might take naps and ask for deadline extensions like “Spanish people.” I found this deeply insulting. This isolated event impacted the way I managed situations like this. It has also impacted my career by strengthening my resilience and reinforcing my commitment to fostering inclusivity in science. Confronting discrimination early in my academic journey taught me the importance of advocating for myself and others, even in challenging situations.
What advice do you have for aspiring biologists?
Never give up, and surround yourself with a great support community. When things are not clear or is a new path, identify your mentor from a senior level who wants to see you grow.
Do you feel that any dimension of your identity is invisible or under-represented/marginalized in STEM?
Yes, as a female soil scientist from South America working in the US, I do feel that both my gender and cultural background are underrepresented in STEM. Sometimes, my perspective and experiences aren’t fully visible or valued. However, I believe these aspects of my identity allow me to bring unique insights to my work and highlight the importance of greater diversity in science.
Slide 2: Research Overview
Take home message of study
Carbon in the soil is good for both farmers and the environment. It plays the dual role of increasing soil health, and fighting climate change because stored carbon does not end up in our atmosphere. But we need evidence for farmers as to which farming practices can help increase soil carbon levels reliably over time. Caro used a long-term experiment from the Kellogg Biological Station Long-Term Ecological Research program (KBS LTER) to help answer this question. She looked at soil samples 25 years after the experiment began. Each treatment was a different agricultural practice, and she could see how they soil carbon in these treatments diverged from each other over time.
Study system
Treatments within the KBS LTER have been grown since 1989 when the experiment began. In 2013, a team of scientists worked to sample soil carbon at this site, 25 years after the experiment began. The team processed the samples to determine the percent, by weight, of each soil sample that is made up of carbon. This is called % soil carbon. They collected samples from 4 different treatments, each with 6 replicate plots:
(1) Conventional: plots grown in a corn-soybean-wheat crop rotation. The soil in these plots is tilled during spring, meaning they are disturbed and turned over. These plots represent how agriculture is conventionally done in the area with standard chemical inputs of fertilizer, herbicides, and pesticides.
(2) No-till: plots that are grown in the same way as conventional, but with one key difference. The soil in these plots is not tilled, meaning it has been undisturbed for 25 years at the time of sampling.
(3) Cover crops: plots grown similarly to conventional, with a few key differences. First, cover crops were added. Cover crops are plants that are planted alongside crops or at times of the year when the main crop is not growing. This means the soil has living plant roots year-round, not just during the season with crops. Second, this treatment had no chemicals added; all nutrients came from the addition of manure. These plots were tilled.
(4) Not farmed: non-agricultural plots growing in a diverse mix of plant species. Plots are unmanaged, but are sometimes burned to keep out woody species.
Photos
(left) Caro working in the labs at the Kellogg Biological Station to confirm the % soil carbon measurements used in the study.
(right) View of the Long-Term Ecological Research experiment at the Kellogg Biological Station where plots have been growing with different agricultural and plant community treatments since 1989.
Slide 3: Key Research Points
Key figures
Compared to conventional agriculture, no-till farming and the planting of cover crops can increase soil carbon. For every 100 grams of soil, there are 0.83 grams of organic carbon in conventional plots, 1.00 grams in no-till plots, and 1.12 grams in plots with cover crops.
Fields with crops grown conventionally – with tillage and no cover crops – had the lowest levels of soil carbon after 25 years. However, when a cover crop was added, these fields had significantly higher soil carbon than the control after 25 years. Likewise, no-till practices, in which seeds are planted into unplowed soil using specialized equipment, also built soil carbon, but not to the same degree as cover crops. This means that after 25 years, the data show that these two farming practices can build soil carbon.
Societal Relevance
These findings show that cover crops and no-till both are ways that farmers can reliably increase the carbon in their soils. Not only does soil carbon fight climate change, but it also provides a direct benefit to farmers due to increased soil health and plant yield. More carbon in the soil means that crop plants have more access to nutrients and water, and will grow better, meaning more profits for farmers. The study findings have significant implications for agriculture. These are practices that should be promoted by policymakers seeking to support farmers as they implement climate-smart agricultural practices that enhance soil health and mitigate climate change.
