 So, I'm a soil scientist and agronomist from Seirad. I've been working in Zimbabwe for seven years now. I mainly work in agroecological region two and three, so I don't have much experience in this kind of very arch ecosystem, but I'm very happy to be here to give some insights about what is soil else and why it should be fully considered in the one-else approach. So I'm sorry, I will start with a definition, what is a soil? So soil is defined as a biological active porous medium that has developed in the uppermost layer of the Earth's crust. So it's basically made of five main ingredients. So you have the minerals, sand, silt, clay. You have soil organic matter, living organisms, gas and water. So as you can see here is average composition of soil at the global scale from FAO. We can see the weight composition, most of the mass of a soil of course is made of the minerals, then you have some water and you can see that the organic matter is a very small percentage of the mass of a soil. Here 3%, but actually many soils in sub-Saharan Africa is much lower than that, less than 1%. So 3% is already quite good soil. So how does a soil is formed? So soil formation is called pilogenesis. So everything starts from a parent material rock and then with interaction with climate and biological activity you have some physical and chemical weathering and with time you have the development of different soil horizons. But it's a very, very slow process. So I want you to realize how slow this is. It takes about 100 to 1000 years just to form one centimeter of soil. So you now understand that soil is a non-renewable resource at human scale and the problem is that currently we are losing soil at a much faster rate than it is formed in many regions of the world through erosion or through bad land management practices. I just want also to mention this citation from a very famous soil scientist. I think it's a very good summary of what is a soil and what are the importance of soil. So essentially our life depends upon the soil. There can be no life without soil and no soil without life. They have evolved all together. So now when you are talking about soils actually we are talking about a huge diversity of soils. FAO has defined 30 major soil types but actually there are many, many more, many subgroups but these are the major ones. So you can see different colors, different horizons and of course all these soils have very different properties, very different characteristics. Some are suitable for agriculture and others are not at all. So now at the global scale here is diversity of soils so you can immediately see that for example in sub-Saharan Africa you don't have the same soil that we have in Europe and this is because of initial rock parent material that was different and the interaction with climate that has led to very different soils in different contexts. Here just a brief focus on Zimbabwe. We could think like looking at the landscapes it's all the same kind of soils but actually it's not at all. There are many, many different soil types even in Zimbabwe as you can see here on this map. So it's important to keep in mind this diversity because when we are talking about soil else we are not talking about a unique soil else. It's always context specific and soil else is also defined according to the type of soil that you are dealing with. Okay so now if we look at a larger scale, so this is the volume occupied by the earth. If we were able to squeeze all the atmosphere in a bowl, this is the volume that will occupy the atmosphere. Same for the water, all the water of the world, oceans, lakes, etc. They could be put in this bowl. But now if you look at soils, this is the volume that occupies all the soils of the world. So you can see it's very, very small and actually this small volume is then spread on all the continents, on all the land. So it makes a very, very thin layer from a few centimetres to a few metres depending on the context. So it's a very thin layer almost like a skin, very fragile. But despite of that, it's actually the support of so many ecosystem services. These are the seven main soil functions that are usually mentioned. So of course soils are involved into biomass production, forestry, agriculture. Huge role into storing, filtering and transforming nutrients, water. It's a huge biodiversity pool. It's also the physical and cultural environment for human activities. It's a source of raw material and it's a huge carbon pool as you will see later. And it's also an archive for geological and archaeological heritage. So now if we look at this figure here on the right, you have the soil science in the middle. Then the following cycle are the seven soil functions that I have just described. The following cycle is ecosystem services that are emerging from these soil functions and the outside cycles are the SDGs, so the sustainable development goals. And you can see the ones with the red dots are all the SDGs where soils are involved. So actually soils are involved directly into 13 out of 17 SDGs. So what does that mean? That means basically it's impossible to achieve these SDGs if you don't manage your soil in a sustainable way. Just a quick look on the importance of soil for climate change and on the global carbon cycle, you can see that the carbon in all the soils, it's huge, it's actually three times more carbon in the soils than in all the atmosphere. And much more than in all the vegetation, all the forest, etc. So I will not focus more on the fluxes and on the 4% initiative we can come back after if we have questions, but there was this initiative launched at the COP21 in Paris about soils for food security and climate, and it is directly linked to this importance of soil for climate change mitigation, adaptation, and food security. So now I'm not sure how many of you know that soil is actually the most biodiverse singular habitat on earth. These are the few pictures of animals, microphones that you can find in the soils. And soil is likely home to about 60% of all the species that we have on earth. So it's absolutely huge. And of course it really depends on the soil groups, on the fauna groups, sorry. So like for example the fungi, most of the fungi are found in the soil, plantae also growing on the soil, but you can see also for bacteria directly related to earth, half of the bacteria are found in the soil. And viruses, significant amount also of viruses are found in the soil. So now just to continue on this biodiversity aspect, if you take just one handful of grassland soil, this is what you get, 50 kilometers of mycelium, so 50 kilometers of fungi, 100 billion bacteria from 10,000 species, 500 meters of plants roots, then you have also protozoa, 100,000 of species, nematodes, algae, etc. So it's absolutely a huge biodiversity. So of course all this soil biodiversity, this soil microbiome is very much related to the one earth concept because soils is actually a source but also a reservoir for pathogens but also for beneficial microorganisms. So as you can see on the picture on the right, you have all this pool of microbes in the soil and then part of these microorganisms are found in our gut, humans, animals through the feed and food, and also in the roots of plants. Plants are able to actually recruit their own microorganisms through exudation of molecules in the soil. So all these microbes found in the soil, they are directly related of course to plant pathogens, plant growth promotion, also antibiotic resistance, bacteria, soil-borne pathogens, etc. So yes, soil health is defined as a continued capacity of soil to function as a vital living ecosystem that sustains plants, animals, and humans. So it has actually emerged from a previous concept that was called the soil quality concept but this concept was much more focused on humans. As you can see, the soil health definition includes also plants and animals. So it's much more inclusive for planetary health. And actually very recently in the last year, there is another concept that has emerged. It's called the soil security concept and in this concept, soil is seen as a common good similar to water and to air. And it's very much used in the policy context because it states also that soil, well, access to soil ecosystem services should be on the same level as other human rights. Okay, so now how we do measure and monitor soil health? There are different types of indicators that can be classified into three main categories. So you have the physical, the chemical, and the biological indicators. You have a list here, so it's very small on the right of very commonly used indicators classified in these three categories. And these indicators are designed in a way that they are informative, so it means we should be able to interpret them. They should be sensitive. For example, you should be able to see the effect of land management or land use change. They should be effective or practical and they should be relevant. And after all these multitude of soil health indicators, they are often integrated into a single index that we call the soil health index. And so for example, the soil health index of a crop land is then compared to a reference soil health index. So usually it's a natural ecosystem on the same soil type, same climatic conditions on the region of interest. I mean, so just to mention that there is no universal soil health index. It's always context specific. So here is a review done by colleagues recently. They analyze different soil health assessment schemes so far. And you can see that in these schemes, most of the time they use chemical and physical indicators. So this is due to a historic focus on soil health indices for crops, crop production. And you can see that so far there are very few assessments that include the biological indicators. So if you wanted to have a more comprehensive soil health index, of course we should have a more balanced set of indicators with at least 20% of each of these categories. And sometimes you might need also different types of indices for different ecosystem services that you want to assess. For example, if you want to assess the capacity of a soil to conserve biodiversity, of course you will have more biological indicators. But maybe for crops, you will have more chemical indicators for climate, maybe physical and chemical, etc. So at CIRAD actually we have developed a tool to assess soil health. It's called the biofung tool. So using also these three types of indicators, chemical, physical and biological, and it has been designed in a way that it is a low cost test and it can be done in situ in the field. So basically you have a list of different analyses that are directly performed into the field and then you are able to rank your soil and compare it to another management, for example. And here is an example on your right, for example on the right you have the forest compared to the left the cassava crop. You can see of course the forest has a much higher index compared to the cassava crop land. So now I just want to mention that 95% of our food is produced on soils, of course, but about one third of the world's soils are already very much degraded. So there are different types of degradation. So it can be biodiversity loss, salinization, nutrient imbalance, compaction, stealing, pollution, acidification, erosion, loss of organic carbon. So there are many, many types of degradation. But there are also some solutions. So the first of all of course is to protect the intact land. Then we need to better manage the crop lands and restore the native cover. So for crop land management it can be achieved, for example, through agroecology which has been defined by FAO by 13 principles. Some of these principles are at the agroecosystem scale like recycling, input reduction, etc. And some other principles are more at the food system level. So now what can we do in crop lands to improve soil health? Well here is just a study we performed recently looking at soil organic carbon which is a very common indicator of soil health. And we look at different practices. And you can see that there is quite a number of practices that have a very positive impact on soil carbon. So it can be biochar, intercropping, manure, rotations, mulch, agroforestry, cover crops, integrated soil fertility management, reduced tillage, etc., etc. So there are a lot of options that needs to be tailored to the local context. So now as we are in one gates my last slide we can wonder what is the impact of conservation areas on soil biodiversity and soil health? We know the impact of course on elephants, on lions, but what is the impact on soil health? So there is actually a huge ongoing project which is called the Soil Biodiversity Observation Network involving 80 countries globally with a lot of countries in Africa as well. And then we are comparing the same land use inside the conservation area and outside the conservation area. So for example it can be a forest inside the conservation area and just outside the conservation area. And then we are taking soil samples of course and we analyze a lot of parameters and we hope to have the conclusion that conservation areas are beneficial also for soil biodiversity and health. I don't have any results so far because it's ongoing but I hope we'll have good results. So a few take home messages. So I hope you are not convinced that soil health is a critical part of environmental health. In my sense it should be fully considered in the one health approach as it is also critical to achieve the SDGs. Then there is no universal soil health index, it's always context specific regarding the climate, soil type, etc. And also depending on the ecosystem services that we want to consider. And there is still a lot of research ongoing on this to have better indexes. So also I think there is a potential for win-win opportunities for different challenges that we have at the global scales like climate change, mitigation, biodiversity loss and what else. I think all of this can be linked just by protecting our soils. So thank you very much for your attention.