Soil biodiversity is integral to sustaining all life on Earth, especially humanity. With the adoption of the 2030 Agenda for Sustainable Development, United Nations Member States have agreed to work toward accomplishing 17 ambitious Sustainable Development Goals (SDGs) globally to improve and sustain life for people and the natural world on which we depend.
Let us explore how soil biodiversity plays a key role in meeting many of these SDGs. Although the SDGs do not refer directly to soil, the strong connection between soil biodiversity and the SDGs is clear. Many SDGs such as food security, water scarcity, climate change, biodiversity loss and health threats are closely linked to or dependent on soil biodiversity.
Deterioration of relationships between humans and soil has resulted in unsustainable management of agricultural, forest and urban ecosystems, leading to environmental degradation and major societal consequences. Soil cannot be untangled from its biodiversity, though these intimate interconnections are not always recognised Soil biodiversity supports human health and well-being (SDG 3) through regulation of many disease-causing organisms as well as playing a central role in agricultural production, supporting SDG 2 (no hunger) as well as agricultural livelihoods contributing to SDG 1 (no poverty), SDG 5 (gender equality), SDG 8 (decent work and economic growth) and SDG 12 (responsible consumption and production).
Life in the soil mediates water flow and uses excess nutrients and pollution, advancing SDG 6 (clean water and sanitation) and SDG 14 (life below water). Carbon cycling from soil biological activity, both in terms of C sequestration and greenhouse gas emissions, are central to regulating climate (SDG 13).
The soil contains arguably the most diverse terrestrial communities on the Planet, and is home to more than 25 per cent of global biological diversity. Moreover, it supports most life above ground via increasingly well understood above- and belowground linkages (SDG 15).
Evidence supports these vital connections between soil biodiversity and the SDGs, and emerging knowledge is shaping actions we can take for a more sustainable future. Soil organisms play many important roles in managing invasive species. Soil biodiversity can help avoid, reduce, and reverse land degradation, sustaining and improving habitat for people and other life on Earth. Long taken for granted, soil biodiversity should be embraced as part of the urgent need to develop a more sustainable future for all.
Soil Biodiversity and the SDGs Food Production (SDG 2): Achieving global food security is one of the greatest challenges of our time. The mismatch between the rate of human population growth and global food production has long been recognised.
We need to double global food production in the coming decades, on less land and using less inputs. The majority of the world’s human population eats a soil-grown, plant-based diet. Even where diets are rich in animal products, livestock rely on soil-grown plants (fish being a notable exception). The quantity and nutritional quality of crops is very much a product of the soils in which they grow. The link between crop production and soil quality is well established.
For example, that 30 per cent of the world’s human population is affected by Zn deficiency is not surprising, given that the soils of almost half of the world’s cereal growing regions are low in Zn. Taken together, it is clear that efforts focused on achieving food security cannot ignore the link between soil and food.
Water quality (SDGs 6, 14): Nutrient exports from agricultural systems are a large contributor to water quality issues in many parts of the world. For example, reports of up to 160 kg of nitrogen (N) and up to 30 kg of phosphorus (P) per hectare can be lost via leaching and surface runoff.
When nutrients reach waterways, they can contaminate groundwater and can also cause eutrophication which can lead to algal blooms and the loss of terrestrial and aquatic biodiversity. Soil biota play an important role in regulating the movement of water into and through soil as well as cycling of nutrients in the soil and water. This can impact their risk of nutrients being lost via leaching.
Similarly, some soil microbes (such as mycorrhizas) play an important role in helping plants to interact with such nutrients, thereby reducing the risk of nutrient leaching. Wider use of agricultural practices that leverage soil biota to manage nutrient availability and loss could contribute significant progress toward water quality goal.
Air quality (SDGs 3, 13): Soil plays an important role in air quality and soil greenhouse gas emissions. When agricultural soils are tilled, the increased oxygen can spur biological activity and respiration of carbon dioxide that can contribute to global warming. Moreover, certain soil microbes under anaerobic conditions (such as flooded or very wet soils) can transform nitrate into the potent greenhouse gas nitrous oxide.
Similarly, other soil microbes can release methane from soil, which also contributes to global warming. Soil microbes have also been reported to help purify air. It is also worth noting that soil microbes and soil fauna can also help to bind soil particles together and improve soil structure in some situations. In doing so they can reduce the risk of wind erosion, thereby helping to reduce levels of dust in the air we breathe.
Soil health (SDGs 2 and 3): The prevention of soil pollution could reduce soil degradation, increase food security, contribute substantially to the adaptation and mitigation of climate change, and contribute to the avoidance of conflict and migration. By taking immediate actions against soil pollution we can thereby contribute to the achievement of almost all the SDGs, with a significant impact on goals 2 and 3.
Climate mitigation (SDG 13) and adaptation: Soil, and the biota it supports, have a central role to play in climate mitigation, and agricultural soils play a key role because they cover such a large portion of the earth. In addition to reducing greenhouse gas emissions from soil (see air quality above), the soil has the potential to sequester large amounts of carbon.
Agricultural practices such as reducing tillage and maximising plant cover can improve soil biological activity and C sequestration. Not only should we mitigate climate change, we must also adapt to it. Soil-provided ecosystem services can help to buffer systems against (resistance) and rebound from (resilience) external perturbations.
Affordable and clean energy (SDG 7): Biofuel can be produced using plant-based feedstocks, using plants grown expressly for this purpose or grown for other purposes and waste materials used in energy production systems. For example, waste materials, such as those from forestry, food processing, wine production, and many others can be processed in various ways (such as pyrolysis, gasification, liquefaction) to extract the energy they contain.
The production of such materials for the most part has their genesis in the soil (for example, crop residues). Moreover, many of these processes produce bioproducts that can potentially be used as a soil amendment (often rich in carbon) and (potentially) nutrients. Furthermore, such materials can provide habitat for soil organisms.
Above-ground biodiversity/biodiversity loss (SDG 15): It is increasingly well understood that above- and below-ground communities are closely linked, and that a change in one can affect the other. For example, a reduction in below-ground diversity can reduce above-ground plant diversity. Similarly, changes in above-ground vegetation can alter below-ground communities.
For example, in a recent meta-analysis it was found that by reducing soil tillage and planting a cover-crop, the formation of beneficial mycorrhizal associations (symbiosis between plant roots and soil fungi that improve plant nutrient acquisition) Contributions of soil biodiversity to ecosystem functions and services 131 was improved. Soil fauna including nematodes, collembola, and mites have been shown to increase grassland succession and plant diversity.
Gender Equality (SDG 5) and Decent Work and Economic Growth (SDG 8): Women are important members of farming communities around the world. Men and women relate to land differently, and their unique perspectives are driven by varying roles, responsibilities, access to resources and control. Understanding these roles, along with power relations in land management, is a primary requirement to achieving effective outcomes when addressing sustainable agricultural development.
Efforts to mainstream gender as proposed by the United Nations Convention to Combat Desertification Gender Action Plan (GAP) as well as recommendations from the United Nations Framework Convention on Climate Change (UNFCCC), the United Nations Convention on Biological Diversity (UNCBD), UN Women, the International Union for Conservation of Nature (IUCN), and the Convention on the Elimination of All Forms of Discrimination against Women (CEDAW) among others convey the importance of gender equality and gender inclusive action in supporting agricultural production and protecting land from degradation.
The numerous recommendations promoting gender equality and human rights and empowerment of women and girls in environmental governance have been proposed by the United Nations Environment Assembly.
Women form a major part of agricultural development with traditional knowledge and skills in farming being closely tied to the maintenance and improvement of land productivity.
Women’s contributions can include knowledge and respect for soil organisms and their role in supporting farming practices. These vital roles of women need to be understood and addressed, on the one hand to enable communities to support women as farmers and as leaders, and on the other hand to ensure that men and women benefit equally, and that inequality is not perpetuated. It is important to enable more equal access to natural resources and to facilitate women in becoming active users and managers of natural resources, goals that are interlinked with SDG 5 and SDG 8.
Source: State of Knowledge of Soil Biodiversity Report by http://FAO.org
