Pablo Souza: «A healthy agroforestry sector should be based on diversification and care of our soils»
Learning from nature is always a necessity. The balance achieved by ecosystems is a very illustrative example of this, as it helps us design economic, social and environmental strategies adapted to each situation, time and place. There is no better way to understand this reality than by noting what Pablo Souza Alonso can tell us about it.
Pablo Souza is a postdoctoral researcher at Campus Terra, a lecturer at the Higher Polytechnic Engineering School (EPS) and a member of the Environmental and Sustainable Forestry Management Unit (UXAFORES). His commitment, dedication and international background endorse a career that pivots around concepts such as soil health, ecosystem restoration, diversification or sustainability, accompanied by a deep interest in training.
Today, it is critical to understand that each piece of the environmental puzzle plays an indispensable role and that the "symbiotic" relationships between them make it possible to weave a mutually beneficial network. However, it is sometimes necessary to focus on elements that are often forgotten, as is the case with soil.
Soil is an essential element in finding most of the solutions we are looking for. Its importance within the food chain is crucial, as is its value as a driver of a circular economy that makes real use of resources. Recovery after a fire, conservation of its quality or its value as a carbon sink in the fight against climate change are essential tasks to move towards a more sustainable horizon.
We talked to him about this and much more in today's interview.
-You graduated in Biology from the University of Vigo, and in 2015, you earned a PhD in Plant Ecophysiology. What motivated you to specialize in this field?
-I think the field chose me. I have always found the triangle (sometimes loving, sometimes not so much) that is established between plants, microorganisms, and soil fascinating. Still, if I have to be honest, it was the confidence that two Uvigo professors (Eva Pazos and Luís González, who ended up being my thesis director) showed me in a subject when I was about to finish my degree.
They told me that I could be helpful in this research, something I had not thought of before, and encouraged me to continue. Fifteen years later, here we are.
-You spent some time in India, where you participated in a project at Babasaheb Bhimrao Ambedkar University to mitigate the impacts of pollutants in urban soils. How can these pollutants influence plant growth?
-The effects are multiple, both at the physiological and production levels, but the idea in this project was, more than identifying the problems they cause (which are well studied), to try to reduce their introduction into the food chain.
Within a circular strategy, the idea was to eliminate a locally abundant invasive species, use its remains to create a residue (biochar) that can be applied in the field and that can immobilize toxic elements, and then test the potential of this research to reduce the amount of free toxins that plants in urban agricultural soils can absorb.
With incredibly high water, air and soil pollution levels, this project's main goal was to try to limit incorporation into the food chain. This matter is especially problematic in urban agriculture in many Indian cities (and many other places), which is often conceived almost on subsistence terms.
-Soon after, you moved to Coimbra, where you focused on reducing the effects of environmental stress on species of agronomic interest through microbial biofertilizers. What is the real potential of these products? Will their use increase in the future?
-The potential is high, but it is difficult to see where we are going. There is a growing demand in different markets, but their use will ultimately be conditioned by price and consumer perception.
Indeed, applying products that favour the establishment of positive plant-microorganism-soil relationships would align with European fertilizer reduction initiatives. Still, specific policies affecting the agronomic sector have yet to be established.
These types of products try to simulate beneficial relationships for plants that already exist naturally. The problem is that if we have degraded soils, sometimes we have to produce or favour them artificially. These products have potential and different markets where they will work, primarily focused on intensive production. Still, I sincerely hope that the future will take us in a different direction.
Instead of applying recipes, I think we should emphasize better knowledge, preservation and recovery of this type of mutual relationship. That means always keeping in mind the concept of the health of our soils.
-You have been a Campus Terra postdoctoral researcher for over four years. What lines of research are you currently focused on?
-Fundamentally, in the study of the quality of organic matter, a key component in understanding soil health. Organic matter could be like the cement that provides structure and, at the same time, the soil's nutrient pantry.
The problem is that although it is fundamental, it is also very fragile. Our work would be focused on understanding different situations, mainly the impacts of forest fires and soils degraded by human activity, and how certain practices can help the mantle or recover it to maintain soil health.
We currently have several projects underway related to the health of our soils after fires. One project involves using by-products from the agri-food sector to improve soils degraded by intensive agriculture. Once transformed, these by-products can improve soils and give greater value to the transformation chain, which would fit into a circular economy strategy.
Another aspect in which I have been very interested for years, and to which I dedicate a lot of time, is the educational aspect. For this, I participate in service-learning projects to try to reduce the problem of forest fires in our environment. These projects are done in collaboration with colleagues from different faculties and supported by colleagues from Education Sciences (true pioneers in developing these initiatives).
-Fires are, without a doubt, one of the phenomena that cause the most damage to the soil and vegetation. What strategies could favour or accelerate the recovery of spaces after a fire?
-There are multiple initiatives and types of intervention, more straightforward or more sophisticated, to promote the recovery of a system. It will almost always depend on the budget you have at hand.
However, a complementary but fascinating question that I think we have to ask ourselves at the same time as what to do is when to do it. The first impression after a fire may be one of emergency, of having to act quickly, but we must remember that systems are resilient and can recover independently.
Knowing the degree of severity (and for this, we can also study the soil's organic matter) can help us decide whether to act. Since the economic aspect will always be a limiting factor in our capacity to intervene in degraded areas, knowing the severity (and therefore the impact) allows us to place our efforts where they are most needed.
Then, there is the issue that fires are multifactorial. We must understand that the way we have arranged the landscape, the situation is not going to get worse.
-What is the relationship between plant ecophysiology and sustainable agriculture or food security issues?
-Well, this question could be approached from many points of view. For me, the key concept here, as in almost everything, is the concept of sustainability.
Ecophysiology tries to understand the relationship between a plant's functioning and its environment. The environment in an intensive production system is fundamentally dependent on human intervention and tends to consume more resources in pursuit of improved production. Is it food insecure? Not necessarily. The problem is the big picture.
In many cases, this intensive agriculture depends on a mix of external inputs, varieties or crops highly adapted to specific conditions, and a high degree of mechanization. What happens when you change one part of this system? Well, the system can collapse.
A good example could be the rise in fuel or fertilizer prices after the Russian invasion of Ukraine. Sustainable agriculture should necessarily involve diversification.
On the other hand, I think that we cannot view food security in isolation from the environment. It seems difficult to have food security if we do not improve production conditions, consume shorter-cycle products and, in short, improve the socioeconomic conditions surrounding agricultural production as a whole.
In addition, there would be confusion of terms for the consumer since sustainable or organic products have labels that can be confusing. Can it be "ecological" or "sustainable" to consume a product manufactured thousands of miles away in Galicia?
-How do climate change and environmental factors influence plant ecophysiology?
-At many levels. It is essential to understand that organisms function well in various temperatures. If you put me to work at 10 degrees without heating, I won't die, but I have to spend energy not to get cold; therefore, I won't be able to work correctly.
Something similar can happen with a crop. If you have a plant that works well in specific conditions and progressively changes those conditions (temperature, water, light), it seems logical to think this plant will not work the same way. If it has to spend more energy to capture water (or not to lose it) or to resist a frost, its production will logically be affected.
We should also remember that changes in environmental conditions can also favor the entry of pathogens and pests that were previously more limited (both by climate and human movement), something we see more frequently every day. In this sense, I would again think about sustainability and diversification: Where will it be easier for a pest to advance rapidly? In a diverse crop with genetic variety or among a set of clones?
-What techniques are most commonly used to study soil degradation or recovery?
-Soil is a tremendously complex and wonderful matrix. It takes hundreds of years to form centimetre by centimetre, but we want to recover it immediately. Many techniques are available to retrieve it; of course, we can even create new soil today.
But perhaps, more interesting than listing the techniques may be to know the different points of view we can use to study its degradation/recovery, as there are multiple angles: we can study physical aspects such as its texture or structure and thus understand its capacity to retain water, have proper aeration and allow roots to expand; we can study the chemical composition and its organic matter and understand the capacity to function as carbon sewers, retain and provide nutrients for plant growth and support life; we can study the microbial communities to know the capacity to fix nitrogen, capture phosphorus or decompose organic matter. We can study the plants that grow in it and know how the recovery is going.
But the most beautiful thing about all this is that all these points of view are interrelated, complement each other and serve to understand the process as a whole.
-What advice would you give to someone interested in developing a career in this field? What professional profiles are going to be necessary in the coming years?
-Well, I don't have a crystal ball, but I can make an exercise of what I would like, at least from the point of view of our community (which is also very exportable). First, we must understand that all this, especially in the case of Galicia, has a context: depopulation and the ageing of our population.
Managing rural geography in demographic decline is challenging (look at the fires). However, being optimistic and considering the scenario for southern Europe, I believe that exciting things can be done in the north of the peninsula, especially in Galicia.
As a power in agroforestry production, the first thing we must do is encourage interest in studying careers in this field, insisting that they are attractive, have roots and create wealth in the territory and full employment. But be careful: We are also responsible for improving investment in recruitment, education and training to maintain the pull among younger people.
Putting more effort into agroforestry transformation, betting on diversification, technification and improvement in the product's value chain (an aspect in which Campus Terra is working well). The improvement of the connectivity of the territory and the enhancement of the quality of the food product. Addressing problems from a multidisciplinary point of view is always good advice, and keeping the soil very present is an essential element where most of the needs reside, as well as solutions to multiple environmental problems. Economic aspects are also fundamental to this multidisciplinary approach.
Aspects such as modelling, remote sensors, or GIS are fundamental for better understanding the territory and decision-making. Similarly, it is essential to be able to work with large databases and integrate the information we have been generating in recent years. Aspects related to climate change adaptation include professionals who know, for example, how to integrate environmental and socioeconomic data to improve situation prediction and increase the resilience of small producers.
We have a European restoration law. It may be that we are not clear about the best restoration criteria, but it is also true that we lack profiles with a greater capacity to understand and restore degraded areas.
Finally, at the level of life advice, we need to slow down (we are going too fast) and invest time in reading and listening. Without going into personal development improvements, living abroad is a great way to value and love what is ours, but also to put aspects that can be improved into perspective.