Regenerating the way we produce food: the key is in the soil

In recent years, the use of the adjective “regenerative” and the concept of “regenerative agriculture” (AR) has expanded among activists, civil society and corporations that call for the renewal, transformation and revitalization of the global food system (Duncan et al., 2021). Today, more than ever, it is clear that the conventional way of producing food no longer works. Multinational agricultural companies have published commitments within their sustainability goals to apply AR practices within their operations or along their value chain. What does this mean? that we are in the decade of regenerative agriculture.

Despite the popularization of the term, it remains ambiguous and there are doubts about what it implies, what it seeks to “regenerate” and how it differs from other farming systems such as organic agriculture and conservation agriculture. Before going into detail about regenerative agriculture, let's focus on the basis of agricultural systems, that is, on the soil.

Soil, commonly known as land, is a fundamental resource for life on the planet, since it contributes to basic human needs such as the production of food, fibers and raw materials; in addition, it is a complex system that, beyond giving life, supports a large part of the organisms that inhabit the Earth. There are many ways to define it, but in general, it is considered to be an unconsolidated organic or mineral material found on the Earth's surface and that provides a natural environment for plant growth. The definition implies that it is something inert, whose only function is to allow a plant to grow. This doesn't do justice to our soils. They are not only sustenance for plants, but are the foundation of our food system; they are dynamic, complex, active in space and time and, above all, they are fragile. Soil is a non-renewable natural resource on a human time scale; it is estimated that 1 cm of soil takes 100 to 400 years to form and is constantly subject to degradation under arbitrary management practices (Weil and Brady, 2017; Siebe and Cram, 2019).

A healthy soil is one that is in a state of self-regulation and stability that allows it to function as a living vital system within an ecosystem and sustain biological productivity (Weil and Brady, 2017), but soil in good condition is more than just a fertile substrate for crops. Whether it is in a pot, garden, park, sidewalk, farm, plot, forest or pasture, soils constitute an active system that is constantly working and provides us with numerous ecosystem services. In addition to providing support and nutrients for root growth, they are home to diverse organisms such as small mammals, reptiles, insects, fungi, bacteria, and others, in such a way that they constitute a habitat for living beings and are home to a large amount of biological biodiversity (Montanarella and Lobos Alba, 2015). On the other hand, another peculiarity of these is that they participate in biogeochemical cycles, which highlight their role in the cycle of carbon (C), nitrogen (N) and phosphorus (P) -which are essential for crop production and yield. In addition, influence the composition of the atmosphere by regulating the storage and emission of carbon dioxide (CO2) and other greenhouse gases such as methane (CH4) and nitrous oxide (N2O) (Oertel et al., 2016).

Not all its virtues end here, the floor also functions as a filter-damper system of various compounds, in such a way that influences water and air quality; constitutes a physical and cultural environment in which most human activities take place and, finally, constitutes a record of geological and archaeological heritage (Commission of the European Communities, 2006). The capacity of soils to carry out these functions is threatened by continuous and increasing pressure resulting from the exponential growth of the global population, land use change, industrial and mining activities, as well as the demand for products (food, fiber, bioenergy) and poor land management (Montanarella and Vargas, 2012). The risks derived from malpractices have been extensively studied and reported by the scientific community, mainly in relation to agricultural practices. For example, it has been reported that intensive activities whose resource management is not sustainable tend to reduce the content of organic matter, biomass, soil biodiversity -that is, the organisms that inhabit soils- and increase compaction and promote acidification, erosion and salinization of soils (Pereira et al., 2018). This has an impact on soil functions and, therefore, jeopardizes its resiliency, that is, their ability to tolerate stress, recover after a disturbance and return to a state of balance again (Siebe and Cram, 2019).

It is estimated that at present about 33% of the world's soils are moderate to highly degraded, which is mostly associated with unsustainable land management practices, that is, there is no or is not implemented such a planned process of establishing which areas have an agricultural or livestock vocation, and which should be priorities to conserve, for example (FAO, 2017). As a result of the above, there is an urgent need to protect the world's soils, as well as to raise awareness and communicate the causes and consequences related to their degradation.

As soils are the protagonists of a large number of benefits for humanity and other inhabitants of the planet, and in order to try to counteract the negative effects of poor land management, agricultural management systems have emerged that seek to reduce the causes and effects of soil degradation. Among the best known are organic agriculture, conservation agriculture and, recently, regenerative agriculture.

Organic agriculture (AO) is a productive approach focused on improving the health of the agro-ecosystem; it focuses particularly on eliminating the use of chemical inputs such as fertilizers, synthetic pesticides, herbicides, and others. Instead, it promotes the use of management practices that allow natural inputs to be reused within the production system (for example, incorporating waste from past harvests) or, failing that, applying inputs of natural origin (FAO, 1999). Although organic products can be placed in a preferential market whose value exceeds the product cultivated under conventional practices, their adoption and application in global agricultural fields tends to be low (20%) (Ibid.). This is particularly related to the requirements and costs associated with organic certification, the availability of bioinputs in the market and the high variability observed in terms of product performance and quality.

Conservation agriculture is possibly one of the most promoted sustainable agricultural systems on a global scale. Conservation agriculture (AC) is defined as a cultivation system that promotes minimal mechanical soil alteration, the maintenance of permanent vegetation cover and crop diversification (FAO, 2019). This system focuses on the conservation and protection of soil, water and biological resources. The characteristics of this system may vary regionally, ranging from a producer who performs manual land preparation, to large corporations that use cutting-edge machinery that allows automated planting and soil preparation with equipment that reduces the risk of soil compaction and disturbance (Lal, 2015).

Finally, regenerative agriculture (AR) is proposed as a solution to address the problems of global food systems. Currently, there is no accepted and standardized definition (Newton et al., 2020), however, there is an international consensus around the principles it promotes: minimal soil alteration, promoting soil fertility, reducing space-time bare soil events, that is, providing constant vegetation cover and diversifying cultivation systems with the integration of livestock. The AR also contemplates a wide range of agricultural practices that seek promote the sequestration of organic carbon from the soil (COS) and strengthen natural nutrient cycling (biogeochemical cycles, in particular, carbon, nitrogen and phosphorus) and, therefore, increasing soil resilience to climate change (Lal, 2020).

In case the above was not so clear, then how is AR different from AO and AC? The AR brings together part of the AO and the AC in order to promote an agricultural management system focused on restore soil functions and health, and with this, contribute to the resilience of agro-ecosystems. While the AO is based on a list of”Do's and Don'ts“, AR seeks to be a more comprehensive management system that is not limited to carrying out individual sustainable activities, but to improving ecological and social processes. The AR approach uses soil conservation as a starting point to regenerate and contribute to the provision, regulation and support of ecosystem services, with the objective of this improving not only the environmental dimensions, but also the social and economic dimensions derived from sustainable agricultural production (Scheefel et al., 2020). The distinction with conservation agriculture is less stark and obvious. There are many similarities between agricultural practices and both seek to conserve soil. The difference is focused on the fact that AR aims to restore soil functionality, in addition to conserving it, while conservation agriculture is only a sustainable agricultural system. The Rainforest Alliance defines CA as the”Journey“, while AR is the”Destination”. I think it's an interesting way to approach both terms, they are undoubtedly interconnected and the first step in achieving a regenerative approach is to consider implementing more sustainable agricultural practices. However, the concept of AR gives more importance to soil as a key part of strategies to mitigate climate change and achieve food sovereignty.

Global agricultural systems face, among many things, three major situations. On the one hand, we have a growing human population that is expected to reach 9.7 trillion in 2050 (United Nations, 2019), whose consumption patterns are governed by global trends rather than local production. On the other hand, we have the climate crisis led by imminent climate change with its associated effects and risks and, finally, the environmental crisis led by the loss of biodiversity and the degradation of ecosystems. This problem is not new and the reality is that it cannot be combated individually; they are interconnected, either directly or indirectly. The world's soils are immersed in these three situations, since agricultural fields, together with food systems and land use change, constitute one third of global greenhouse gas (GHG) emissions. In addition to the above, poor agricultural management has led to them being considered sources of ecosystem degradation and contamination of water bodies, which contribute to the loss of biodiversity. However, soils can and should be part of the solution. The AR seeks to emphasize the potential of soils to combat climate change while promoting sustainable agricultural practices that make it possible to produce quality food and conserve associated biodiversity. It may seem fictional, but we are still in time to change the course of things.

As we already know, population growth and food shortages in some parts of the planet are a reality. La Green Revolution sought to counteract the problem by promoting an intensive and technified agricultural scheme that favored the establishment of crops and the abundant use of chemical fertilizers, pesticides and herbicides. Without a doubt, this system was encouraging in the fight to “end hunger” by allowing high agricultural yields, however, nature has told us that it is a failed and unsustainable model of agri-food production. As a result of the above, it is pertinent to ask ourselves, is AR capable of producing enough food for a constantly growing population, and at the same time, reducing and offsetting part of anthropogenic greenhouse gas emissions?

To answer this question, it is essential to say that the food crisis must be rethought based on whether more food really needs to be produced. Today, global agriculture has the capacity to feed 10 billion people. Recent figures indicate that the global population is 7.9 billion people (Worldometer, 2022), which implies that plenty of food is produced. Conventional agriculture does not seek to feed people; it seeks to generate profit and added value. Around 30% is wasted and food tends to be poorly distributed. We must stop the vicious cycle around “producing, wasting, degrading, polluting and producing more” that we have perfected in recent decades. Otherwise, we will only be able to ensure that the expansion of agricultural and livestock fields continues, implying another vicious cycle that is just as dangerous: “deforestation, loss of habitat and loss of biodiversity”. One of the goals of AR is to produce more from less: smaller area, less need for chemical inputs (fertilizers, pesticides), less water used for irrigation, lower GHG emissions, lower risk of soil degradation and lower energy expenditure (Lal, 2020). Simultaneously, it seeks to improve yields, soil health and quality, promote carbon sequestration, maintain biodiversity, economic resilience and promote food sovereignty. Therefore, in my opinion, the answer is yes. AR is capable of producing enough food for the current needs of the population, since the problem is not food shortage, but poor distribution of food combined with production systems that are harmful to life.

However, is AR capable of contributing to reducing the climate crisis? Like everything in AR, let's return to the floors to explain why. Soils constitute the main terrestrial reservoir of C and N, since they store around 2,500 petagrams (Pg) of carbon -it is worth mentioning that a petagram is one billion metric tons of carbon-, of which approximately 1,500 Pg of C corresponds to soil organic carbon, and 136 Pg of total N in the layers found in the first meter of soil depth (Weil and Brady, 2017). Its contribution to GHG emissions is associated with poor agricultural practices that include the use of intensive/conventional tillage, excessive use of nitrogen fertilizers and flood irrigation. These practices influence the main processes that give rise to GHGs - such as carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) - which, in a very general way, are soil respiration, methanogenesis, nitrification and denitrification. Let's see what all this means: soil respiration is carried out by soil macrofauna (worms, mites, ants, mealybugs, and so on), soil microfauna (mainly fungi and bacteria) and by plant roots. All of these organisms breathe in a way similar to how we do and release CO2 in the process. This is a natural process, and in a balanced system, the same amount of CO2 is expected to be sequestered by the photosynthesis process as what is released by respiration processes (Lou and Zhou, 2006). However, the poor management of agroecosystems has caused an imbalance in cycles, causing many of the planet's soils to be sources of GHGs rather than sinks.

In relation to methanogenesis, most methane production in soils takes place in the absence of oxygen. When water stagnates or a flood occurs, it leaves no room for available oxygen, so an anoxic condition is generated. AR promotes irrigation techniques focused on saving water, such as drip irrigation; this technique allows irrigating agricultural fields in a controlled manner and prevents soils from reaching anoxic conditions and, therefore, prevents the production and release of methane.

Finally, the nitrification and denitrification processes are nothing more than the transformation of organic N into forms that can be assimilated by plants. These processes are involved in the natural cycle of terrestrial N, however, they are also the main sources of nitrous oxide. It is enough to clarify that nitrous oxide is a GHG with a heating capacity 300 times greater than carbon dioxide. Nitrification is an aerobic process, that is, it requires the presence of oxygen to be carried out, while denitrification is an anaerobic process and, therefore, occurs more easily in flooded soils, lacking available oxygen. The excessive use of inorganic fertilizers rich in N promotes that these two processes occur more quickly and nitrous oxide is released into the atmosphere and part of the element is lost in the form of nitrate (NO3-) to bodies of water. The use of organic fertilizers allows for a more efficient management of the element, since its release through biological activity is slower and its loss to the atmosphere or to bodies of water can be reduced.

As we can imagine, AR is capable of contributing positively to the climate crisis, since it promotes agricultural practices focused on reducing emissions of these gases, mainly nitrous oxide and methane, and at the same time, promote carbon sequestration so that soils act as sinks and not as GHG emitters. These agricultural practices focus - to a greater or lesser extent - on increasing the soil's organic carbon (COS) content. As mentioned previously, COS constitutes only a fraction of the total carbon found in the soil and is in constant movement (cycling) between the different carbon compartments within the system. COS enters the soil through plant residues and exudates that are transformed by heterotrophic activity, that is, by the action of those organisms that are unable to produce their own food, so they feed on external sources of carbon (macro and microfauna, as well as fungi and bacteria) in the soil. Through this process, organic material is transformed into a complex biogeochemical mixture of plant compounds and products resulting from microbial decomposition in various stages of decomposition (FAO, 2017b; Weil and Brady, 2017). The compounds of this complex mixture of wastes can associate with soil minerals and/or be occluded within soil aggregates, ensuring the permanence and resistance of COS in the soil for months, decades, centuries or even millennia (Schmidt et al. , 2011). The transformation of soil organic matter is crucial for the functioning of ecosystems; it influences soil structure, nutrient retention and release, water availability, retention and quality, and soil fertility and productivity in the short and long term. Additionally, there is a relationship between COS content and soil biodiversity. Soil is considered a reservoir of biodiversity that houses multiple species of animals and microorganisms, so much so, that it is estimated that one gram of soil can hold up to 1010 bacterial cells (Roesch et al., 2007) that act as the main driving agents of nutrient cycling, regulating the dynamics of soil organic matter, GHG emissions and carbon sequestration. In turn, the quantity and quality of organic matter influence the activity of soil biota that interacts with the roots of the plant (FAO, 2017b). Therefore, the higher the COS, the greater the soil fertility.

Despite the importance of COS, agricultural practices and land use change have resulted in the loss of between 25 and 75% of the C contained in agricultural soils (Lal, 2004; 2018; Lorenz & Lal, 2018). As a result, the initiative has emerged to Recarbonize our soils through the implementation of sustainable agricultural practices. The potential of soils to sequester carbon has been promoted by various initiatives, programs and governments and, recently, its potential within the carbon market has been seen. The development of agricultural carbon credit projects presents a great attraction for large companies that seek to offset and reduce their emissions along their value chain, as well as for governments that seek to meet their environmental commitments. Including soils in this market is an astute strategy that will encourage producers and land owners to adopt sustainable or regenerative agriculture practices that promote carbon sequestration and preserve all the resources and benefits that this entails.

The question remains as to how much carbon can be sequestered through the adoption of these agricultural practices. The reality is that there is no perfect formula or a minimum/maximum number of tons of carbon to be sequestered. Agricultural management must be context-specific, since soils depend on various environmental, climatic and geological factors. In this way, the spatial variability of soils and their characteristics make it impossible to establish ideal agricultural management for the entire Earth's surface. On the other hand, the social factor must be considered; the cultural and economic context of the owners of the land. Food sovereignty must exist in the process of recarbonizing the planet's soils. People should have the right to decide how they market and produce their food. The AR approach allows the inclusion of diverse cultivation systems, since it is not based on a system focused on applying practices in a specific way, but rather promotes principles that can be followed through various methods implemented in multiple ways.

In Toroto, soils seem to us to be an indispensable resource and one of imminent need to protect and restore. For this reason, AR is our way of caring for and regenerating them. In response to the extensive research that supports the urgent transition we must make to care for our planet, we believe that a future compatible with life requires comprehensive actions, and therefore, intersectoral cooperation. The above is an invitation to join and be part of the change. We know that sometimes a glimpse of the future can give us a fuzzy picture, however, you and your company are not alone; we create change together. You don't need to be a big producer. We all play a role in ensuring the sustainability of our planet. Whether from our plot, our office or our home; we are all directly or indirectly connected to ecosystems, in particular, we depend on agro-ecosystems for food and survival. Let's remember that our soils are more than soil and substrate for plants, they are reservoirs of life and carbon sinks. It's time to go out and contemplate what's in front of us and to appreciate everything it gives us without demanding anything in return.

About the author:

Carla studied biology and has a master's degree in Integral Ecosystem Management from the UNAM. She is passionate about soil ecology and is convinced that proper soil management is key to the fight against climate change.

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