Dr. Desire Djidonou is leading the university’s efforts in controlled environment agriculture research
When most people picture farming, they imagine wide-open fields and endless rows of crops stretching toward the horizon. But inside the greenhouses at East Texas A&M University, a newer kind of farming is taking shape, one that doesn’t require soil, takes up only a fraction of the space and could help feed the growing cities of tomorrow.
Leading this effort is Associate Professor Desire Djidonou, Ph.D. Supported by more than $1.5 million in USDA grants, Djidonou’s projects are advancing food production science while training the next generation of agricultural leaders.
We sat down with Djidonou to see what makes urban agriculture and hydroponic systems so important for our future.
Let’s start at the beginning: How did you first get involved in agriculture?
I have been involved in agriculture from an early age in my home country of Benin, in West Africa. In Benin, 12th-grade students are eligible to take a national test to earn one of just 20 government-funded scholarships to one of the national schools. After taking the test, I was selected as a scholarship recipient and attended the College of Agricultural Sciences at the University of Abomey-Calavi. From there, I moved to America to complete graduate studies at the University of Florida. I first became involved in the A&M System as a research associate with Texas A&M AgriLife before being hired here in Commerce.
So, for those who don’t know, explain what hydroponics is exactly.
To put it simply, hydroponics is the method of growing plants without using soil. Instead of soil, we use substrates or media into which mineral-rich solutions are added to provide all the essential nutrients the plants need for optimal growth and development; this is called substrate culture. Another form of hydroponics is called water culture where plants are grown directly in the nutrient solution without any substrate. In a sense, hydroponic systems enable growers to have full control of the root zone environment of the plant, resulting in an increased efficiency of resource use, especially fertilizer and water.
What are some of the main benefits of growing plants hydroponically?
Hydroponic systems are in fact an integral component of controlled environment agriculture (CEA), which in a broad sense is the production of crops in an enclosed structure such as high tunnel, greenhouse or indoor vertical farming. This is done using a variety of techniques to optimally regulate environmental factors such as light, temperature, humidity, water and nutrients.
As a result, in terms of key benefits, CEA hydroponic systems can maximize productivity with much less acreage and resource use efficiency (minimal inputs such as water, nutrients and chemicals) and produce of higher quality in comparison to conventional field-grown systems. Tomatoes grown Hydroponically can, for example, achieve an 18-times greater yield than field-grown tomatoes using about one third of water for irrigation. CEA hydroponic systems can also provide consistency in supply as the production is independent of external weather conditions or seasons.
What does the future of hydroponic growing look like in the U.S.?
Hydroponic greenhouse production is not a futuristic industry anymore. Many of the high-quality fresh vegetables such as tomatoes, colored bell peppers and seedless cucumbers we enjoy are already widely grown in hydroponic greenhouse production systems located in the U.S. Yet, we still rely on imports of these items to have them available year-round.
With the growing consumer demand for locally-grown fresh produce, CEA hydroponic systems are becoming increasingly popular for the production of various vegetables. In support of this industry, many universities are developing and expanding research and teaching programs in CEA to generate knowledge to optimize these systems.
How have these research grants impacted how we can teach our students?
Overall, outcomes of these efforts will lead to a continuous growth of the hydroponic vegetable industry.
With these grant funds, we now have a new environment-controlled greenhouse fully equipped with a Dutch-bucket hydroponic system and automatic fertigation injection system for growing fruiting vegetables such as tomatoes and bell peppers. The new greenhouse is also equipped with a nutrient film hydroponic system with tunable LED lights for growing leafy greens with supplemental lighting.
With these hydroponic systems, we have been training our graduate students in greenhouse hydroponic research trials related to supplemental lighting effects on lettuce growth and fresh yield, grafted tomato growth and yield responses in different hydroponic substrates, etc. We have also developed new hydroponic crop production course providing hands-on training opportunities in controlled environment hydroponic systems to our undergraduate students. I should also mention that we also get to donate fresh tomatoes harvested from our greenhouse experiments to the Lion Food Pantry.
What fascinates you the most about what you’ve discovered in your research into hydroponics?
Our urban horticulture research program focuses on developing best management practices for the sustainable production of major vegetable crops in controlled environment hydroponic systems. Working with our master’s students, we have first identified suitable lettuce cultivars for hydroponic production in greenhouse and indoor vertical farming systems.
In a follow-up experiment, Joshua Osuch, one of my graduate students, has been evaluating the effects of supplemental lighting on growth and yield traits of selected lettuce cultivars. He grew the lettuce cultivars in Fall and Winter when there is less daylight and provided them with two supplemental light recipes and no supplemental light as control. He found out that both supplemental light treatments significantly increased the yields of these lettuce cultivars compared to the control. So, we now know the right amount of supplemental light needed for lettuce to grow optimally in the off-season. In addition, two other students have been working on testing different soilless substrates to select the best substrate for enhanced hydroponic tomato production in greenhouses.
Students have had the opportunity to attend the annual conference of the American Society for Horticultural Sciences to share findings of their experiments with other participants. This is beneficial to our students as it allows them to learn from our researchers while also building their network for opportunities to continue with their graduate studies.
I understand that we also have a hydroponic lab at our Dallas Site. Could you tell me a bit about it?
That really speaks to the broader benefit of controlled environment agriculture systems which can be installed even in densely populated urban areas not quite suitable for conventional soil-based agriculture. The Dallas site is a good example of that. (For reference, the hydroponics lab is on the 20th floor of the high rise and receives little to no natural light.) This type of CEA system is called indoor vertical farming (IVF) where plants are grown vertically in multitier designs using electric lamps as the sole source of light and HVAC units for humidity control as well as systems for injecting carbon dioxide in the space to enhance photosynthesis activities of the growing plants.
Resource use efficiency is of paramount importance to make the IVF systems more sustainable; this involves among others, selecting highly efficient light fixtures, especially LED lights for these systems. We have recently acquired some narrowband LED lights for our Dallas lab and we will be testing them soon to come up with specific light recipes for growing selected vegetable crops (spinach and other less-studied leafy greens as well as dwarf tomatoes).
What do you have planned for future research?
We have been working on lettuce and tomatoes for the past few years. I am currently exploring additional grant funding to also initiate research on others high-value vegetable such as colored bell peppers, which are usually grown in the controlled environment hydroponic systems. This will enable us to continue to train our undergraduate and graduate students in the emerging controlled environment agriculture industry and urban agriculture.
For more information on the College of Agricultural Sciences and Natural Resources, visit their webpage.
Article source: Ryan Scott – East Texas A&M Marketing and Communications
Featured Photo: Dr. Desire Djidonou inside ETAMU’s newest greenhouse. | Photo credit: Jason Connel, East Texas A&M Office of Marketing and Communications
