(Transcribed by TurboScribe.ai. Go Unlimited to remove this message.) Welcome to Mind the Globe, the podcast where we dive into some of today's most pressing global challenges.
We are a team of seven international students from the Junior Research Lab at Institut Agro in Montpellier, here to explore the issues that shape our world and our future.
Hello and welcome to Mind the Globe, a podcast from seven international students from Institut Agro in Montpellier.
In this episode, it's me, Anna, and I'd like to introduce you to agroforestry, a promising strategy to cope with global challenges.
For this, I had the pleasure to talk to Dr. Marie Gomes.
So hello, I'm Marie Gomes.
I'm a researcher at INRAE, the French National Institute for Agronomical and Environmental Research, and I'm an agronomist.
So I studied agronomy and then I did a PhD on plant pathology, and now I'm working in an agronomy unit, so it's unit ABSYSS for diversified agrobiosystems, agrobiodiversified systems, or whatever, ABSYSS.
And I'm working on agroforestry, more specifically.
So I'm working on the associations between plants and crops or animals.
And I've been working there for 10 years.
To learn more about her, I asked Marie about her motivation for research.
I was always interested by research.
So it's a calling, I could say, since I was maybe like 10 or something like that.
Before that, I wanted to be a veterinary doctor, and then I wanted to work on research, and more specifically on biological research.
I did not know about agronomy then, but then I discovered agronomy during my studies and I found it very interesting because it has both interest in scientific questions to understand how things work, and also it has a societal impact because, well, thanks to agronomy, we can improve the way we grow food that we eat.
I think agroforestry is a very interesting topic, again, both in terms of scientific interest and in terms of societal relevance.
It's interesting scientifically because it relies on complex systems and complex interactions between the elements of the system.
So it's very interesting to study and there are so many things we still don't know.
So that's very interesting.
And at the same time, I think it's one, not the only one, of course, but one of the very interesting levers for agroecology to increase the ecosystem services that is produced by agricultural landscapes.
But what exactly is agroforestry?
At its core, agroforestry is the intentional integration of trees into agricultural systems where crops or livestock are cultivated.
Instead of isolating trees, crops and animals in separate zones, agroforestry combines them into a single, interconnected system where the components support and benefit each other.
This does not only produce food, but also wood, as well as ecological services.
For centuries, communities have integrated trees with crops and livestock to maximise the use of land and resources long before the term agroforestry was even coined.
Agroforestry can be grouped into three main types of systems.
Let's explore what these systems look like.
The first type is agricultural systems, which integrate crops with trees.
A common example is home gardens, where farmers grow a mix of trees, crops and crops in small managed areas near their homes to provide food, fire, wood and other resources.
In West Africa, agroforestry practises like intercropping millet with trees have long been used to improve soil fertility and provide food security in arid regions.
Similarly, in Central America, traditional shade-growing coffee systems combine coffee plants with taller canopy trees, enhancing biodiversity and protecting crops from extreme weather.
Another example is alley cropping, where rows of trees and shrubs are planted alongside field crops.
The trees help to protect the crops from wind, improve soil fertility, plus they provide products like timber or fruit.
Alley cropping can be seen on the Domaine de la Restinclière, around 15 km north of Montpellier in the south of France.
It's one of the oldest and most extensively studied agroforestry systems in Europe.
There, the over 20 tree species were planted in rows to ensure compatibility with modern mechanisation.
Between the long rows of trees, they planted a few rows of vine grapes or grow field crops such as wheat.
The second type is silvopastoral systems, which bring together trees and livestock.
In pastures, trees can provide shade and shelter for animals, which reduces heat stress and is good for the welfare of the animals.
The trees can help stabilise the soil and also provide food for the animals.
Implementing this system can also improve forage availability by creating a more diverse habitat that can support wildlife.
A well-known example is the Dehesas in Spain, an old system where oak trees are scattered across grazing lands.
The trees provide acorns for pigs and firewood.
Finally, we have agrosilvopastoral systems, which are the most integrated of all.
These systems combine trees, crops and livestock into a single space.
For example, home gardens can also include animals.
Imagine some chickens pecking around in the marsh, provided by a mix of crops and trees.
So as you can see, within agroforestry, we have quite some diversity in the systems.
Agroforestry as a concept is applicable to many different environments and farming goals.
You could say that the magic of agroforestry lies in its ability to provide essential ecosystem services while boosting productivity.
Research shows that trees and agroforestry systems provide soil fertility, enhance biodiversity and optimise the use of water and nutrients.
This is especially important in challenging environments, like arid regions and areas prone to climate extremes.
Marie will explain this further, but the main concept of agroforestry is how it creates synergy between its components.
The process comes from the modification, for example, of the microclimate, so the shade of the tree during the day, but also the mask of the tree on the sky during the night buffers the temperature.
So it's cooler during the day, warmer during the night.
And that can be useful to avoid, for example, frost in the spring, early, early or rather late frosts that become more damaging due to climate change, because due to warmer winter, the crops will, for example, fruit trees or grapevine will open their buds more early.
And so at a time when there is still a risk of frost.
And so if trees buffer the temperature, there will be less risk of frost.
And of course, for the cooler temperature in the shade, it's interesting also in the context of climate change to avoid heat stress during the hottest part of the day.
One main advantage is that agroforestry can yield more per cultivated area than keeping the field and tree crops separated.
How is it possible?
Basis of agroforestry is the complementarity between the different species that you associate.
For example, when you associate trees that shed their leaves, so deciduous trees with winter crops, then you have complementarity during the year.
When you sow the crop in October, for example, the leaves of the trees are falling.
The crop can grow during the winter.
And finally, when the trees open their buds, the crop has completed most of its life cycle.
Of course, not completely, but most of it.
And when you harvest this winter crop in June or July, then the trees can still use the light for the during the summer, for example.
So you have a temporal complementarity.
So better use of the light resource.
And there are also complementarities in time and in space for the use of nutrients and water.
For example, if trees can go deeper than the roots of the crops, then it can exploit resources that are not accessible to the crops.
So it creates complementarity.
And through complementarity, you can increase the total productivity by associating the two species rather than separating it.
And this has been, as you said, often claimed, but it has also been proved in a few cases.
And for example, in my team, I was not there at the time, but in my team, we have proved that for a poplar and associated with arable crops, the productivity of the poplars were reduced compared to the forestry control.
The productivity of the crop was reduced compared to the full crop, full sun crop.
But by associating both, we were producing 30% more than if both crops were separated, both species.
And there are more benefits.
We could say that agroforestry offers a triple win, ecological, economic and social benefits.
Ecologically, it improves soil health, provides wildlife habitats, enhances water use efficiency.
Economically, it increases resilience to climate change, reduces the risk of crop failure and divisives farm income streams through both crop and wood production.
And socially, it builds resilience for communities.
Agroforestry systems help farmers to adapt to climate change by stabilising yields and reducing vulnerability to extreme weather events.
Hearing all of these benefits in impressive numbers, you might wonder why there isn't agroforestry everywhere.
The problem is that there are many barriers to adoption of agroforestry.
And these barriers are both barriers of knowledge and skill of the farmers, because the farmers are farmers and they are not tree growers.
They are barriers of the regulation and in particular the impact of, well, all the regulations were thought in a mind of separation of forest and agriculture.
And so combining both is difficult and people have to overcome a lot of barriers.
There are also economical barriers because it's expensive to instal a new agroforestry system, it's expensive to manage it at the beginning.
There are technical obstacles too, due to mechanisation, for example.
So trees can be seen as, well, obstacles in a field.
Also regulatory barriers make it hard to combine agriculture and forestry because the rules are often set up to treat these as entirely separate sectors.
Economically, the cost of establishing an agroforestry system can be prohibitive, especially for smaller farms.
And then there's the technical side.
Modern farming machinery and practises aren't always compatible with integrating trees into farmland, which means farmers need new tools and training.
So what could be done to overcome these challenges?
Experts suggest a few key measures.
First, policy alignment is crucial.
Agricultural and forestry policies need to work together to make it easier for farmers to adopt agroforestry.
Second, financial incentives like grants and subsidies should be expanded to help farmers cover the cost of setting up and maintaining agroforestry systems.
Third, providing technical training and support will ensure that farmers have the skills and resources they need to manage these systems effectively.
Let's take a look at the current situation of agroforestry support.
Subsidies are key to encouraging farmers to adopt these systems, and while some regions are still catching up, others are making advances.
In developing countries, much of the financial support comes from international programmes.
Initiatives like the Global Environment Facility offer funding for agroforestry projects as part of their work to combat climate change.
In countries like Kenya and India, farmers are paid to plant trees and can be rewarded for the carbon they store in their agroforestry systems.
In the European Union, agroforestry is supported through the Common Agricultural Policy.
Farmers can receive funding to plant and maintain trees on their farmland because of the environmental benefits agroforestry provides, like storing carbon and boosting biodiversity.
In France, the National Agroforestry Development Plan offers grants, training, and technical support to help farmers adopt these practises.
To expand agroforestry globally, governments and organisations need to align their policies, offer better financial incentives, and make funding easier to access.
If they do, more farmers can adopt these systems, helping to tackle global challenges like climate change, food security, and biodiversity loss.
And as always, we need more research to promote the best version of agroforestry.
Here's what Marie told me.
I think we have still a lot to understand on the interactions between the species and the crop management, not only crop, but the management of the system.
Because we start having some clues about the effect of management of our systems.
We have knowledge based on ecology, on the interactions between species, but the complex ways in which management can influence interaction between species is very interesting.
And in agroforestry, there are so many different ways in which we can modify the system, both when you design the system, so at the beginning, when you decide which species to plant, how to plant them, with which special design, for example, of the system, and also when you manage the crop, the soil, and the trees.
Now let's take a look into the development of agroforestry research.
The formalisation of agroforestry as a science discipline began relatively recently, in the mid-20th century, as researchers recognised the potential of these traditional systems to address issues like deforestation, soil degradation, and food insecurity.
At first, agroforestry research primarily focused on documenting these practises, particularly in tropical regions, where they were already widespread.
Early methodologies were largely observational, concentrating on tree-crop interactions, yield benefits, and basic ecosystem dynamics.
One of the key developments during this period was the introduction of biophysical theories like the central agroforestry hypothesis proposed by Kennel and colleagues in 1996.
This theory suggested that the success of agroforestry systems relies on trees acquiring resources like water, light, or nutrients that crops cannot otherwise access.
Over time, the focus expanded to address global challenges like climate change, biodiversity loss, and land degradation.
Today, agroforestry is recognised as a key strategy in sustainable agriculture.
Notably, research in temperate regions still lags behind studies conducted in tropical areas.
Advances in digital tools and modelling have accelerated progress, offering cost-effective and scalable alternatives to long-term field experiments.
There are two aspects of digital tools on which I work and I find interesting for agroforestry.
The first one is a more classical approach.
It's models.
Since we work with perennial crops, perennial trees, perennial plants, it's very difficult to predict the future.
And in that aspect, modelling helps us project in the future, helps us, well, of course we also need experiments.
But once you have followed an experiment and you have parameterized the model, it can help you extrapolate to other conditions.
And that's also a specificity of agroforestry is that since it's a relatively new subject, there are not yet mature agroforestry systems everywhere for different types of systems, for different soils, in different conditions, et cetera.
And so modelling is the only way we can extrapolate from the few experiments that we have to the whole possible combinations possible in agroforestry.
So that's the more classical digital tools.
We did not call them digital at the time, it was not fashionable.
And the second set of digital tools is the tools that allow interacting with the users directly.
So we can change the model of research where you have researcher who publish papers and then you have technical institute who take the knowledge and adapt it to local conditions.
And then you have advisors that advise the farmers.
With digital tools, there can be a more direct link between the users and the producers of the knowledge.
And I find it interesting, even if I'm sure we don't use the full potentiality of these digital tools, but we are trying to devise new ways to collect information, for example.
So it's all what is called citizen science, for example, that was already possible before, but it's completely multiplied thanks to the possibilities of digital tools.
And of course, also there is a digital in terms of sensors, so sensors that collect in real time a lot of data and then all the processing power that is needed to to process the data.
And that gives new possibilities to study agroforestry system that are complex and that are characterised by their high spatial heterogeneity.
So before you had one sensor that was worth 1000 euros each, so you had maybe two of them and put one in agroforestry, one in the agricultural control, and you were happy to have one set of data.
But you were completely missing the spatial heterogeneity.
And now some people and I will start advising a new PhD who will start soon on a new high low tech sensors to better characterise the environment and better characterise the crop and to get new knowledge on how the plants react to its environment and hopefully improve the management adapted to local conditions.
To me, these digital tools are very promising for the future of agroforestry from advanced models that help us predict how the systems might evolve under different conditions to real time sensors that give us a deeper understanding of the complexity.
It's clear that technology is bringing even more potential to agroforestry research and practise.
But agroforestry is not a magical solution.
To conclude, Marie gives us an insight into what she wishes us all to remember.
I think that one important lesson that agroforestry teaches us is that nothing is true forever in all conditions.
So what I really like about agroforestry is that, of course, we know the mechanisms that take place, but the whole point is not on knowing what happens, but on the balance between the different mechanisms.
And this balance is really dependent on the conditions, on the management.
And so it's interesting to see that you cannot devise a system that is one size fits all.
It's not specific to agroforestry, it's also the case for all agroecological principles.
You have a set of principles, but the balance between the different mechanisms, the positive and the negative one, will depend on the context, both the soil and climate and also the management.
And so there is no place for dogmatism.
It's always a matter of finding the good combination and the good management that will fit a specific set of conditions and a farmer's objective, for example.
And here we are.
Thank you, Dr. Marie Gosme gom, for sharing your insights with us on Mind the Globe.
And thank you for listening.
The next episode will be about seed inoculation for main crops in zero carbon agriculture.
I hope you will join Kitano to learn more about this.