Gourav Sabharwal
Soil-quality is a key determinant of sustainable agriculture that is influenced by the various physical and chemical properties whilst considering the influence of climate and external inputs. Various current land and crop management practices have resulted in degradation of soil quality, thereby, adversely impacting the sustainability of agricultural inputs. For example, excessive use of fertilizers has resulted in a nutrient surplus in parts of the world, resulting in water and air pollution, and disturbing human health and the environment. On the other hand, an imbalance in the supply of nutrients can reduce soil fertility and organic matter, affecting soil microbiota and resulting in erosion. A healthy soil ecosystem involves design and management to maintain a healthy and sustainable ecosystem that is not limited to nutrient cycling, biological control of biotic and abiotic factors and regulation of water and air supply. Many approaches are considered to reverse the changes of reduced soil quality while trying to replenish them. United Nations Convention to Combat Desertification (UNCCD) recommends systematic conservation agriculture practices that integrate crops with livestock and trees to create a healthy and complementary ecosystem. Approaches such as switching to biological plant growth agents instead of synthetic ones, and an integrated approach to water and soil management are also being pursued. An emerging approach, established by several research activities, is that use of carbon sequestration will have a positive impact when it comes to promoting a healthy soil ecosystem. Apart from increasing the soil quality and promoting plant growth, it can increase water availability to plants, reduce the impact of pollutants and improve soil and plant resilience to external environmental conditions. It’s also equally important to establish preventive measures to prevent further degradation of soil. A comprehensive action plan is needed to implement soil-friendly processes on a global scale. This requires the involvement of stakeholders across all societal segments, including farmers, researchers, trade associations, industrial participants, and the public. Development of qualitative and quantitative indicators that can continuously monitor soil health and help in developing/modifying an intervention plan to improve the nutrient content, soil microbiota, access to water and air can go a long way in maintaining soil health. Tax credits, financial aid and legislation that encourage the adoption and long-term implementation of soil friendly practices can help farmers choose agricultural inputs that don’t harm the soil while replenishing it. “A growing focus on sustainability has resulted in an evaluation of agricultural activities and their contribution to climate change. Various studies have underlined the potential environmental degradation that had resulted in the reduced nutrient availability to crops and increased susceptibility to environmental stresses and pathogens.” The role of soil microbiota is also crucial for establishing sustainable agricultural practices. Treating the soil ecosystem as a diverse food web and regulating the growth of beneficial microbes and plant pathogens can help in establishing a healthy soil microbial population that can help in promoting plant growth and yield but also help in maintaining healthy soil. Soil microbiota is often used as an indicator for soil health; hence, careful selection of growth promoters, plant protection agents, and microbial inoculants that are of biological origin causes minimal impact on the soil ecosystem as opposed to chemically derived ones. Further, they can also help in water conservation and improve water availability to plants.
Soils help meet societal needs, providing food, energy, and nutrients. They also help minimize the impact of climate change and promote healthy ecosystems. Below are three reasons why soil is so important:
Soil organisms ensure sustainable food systems and mitigate climate change. Plants and animals rely on soils for food, shelter, and more. Soil is also home to fungi, algae, and unicellular and multicellular organisms that are invisible to the naked eye, such as bacteria and protozoa. As they move through the soil, microorganisms help improve drainage and soil structure, making soil more fertile and productive. Soil plays a critical role in the carbon cycle: the continuous process by which carbon atoms travel between the atmosphere and Earth. For example, in breaking down organic matter in the soil, microorganisms release carbon dioxide into the atmosphere and create nutrients and minerals that feed plants and crops. Soil also naturally absorbs carbon from the atmosphere in a process known as sequestration. Healthier soil absorbs more carbon, reducing the effects of greenhouse gases.Soil’s essential roles Farmers rely on soils to make food production possible, feeding people and livestock. Soil also acts as a purifier: As surface water travels through the ground to replenish aquifers, soil filters out toxins and impurities, making it drinkable. Soil also provides raw materials for infrastructure. For example, soil is an important element in making bricks for buildings.
One can consider these resources for insights into soil’s role in sustainability and creating a healthier world.
4 Awe International, ‘Saving Our Soils for Future Generations’: An exploration of why healthy soils are essential for sustainable societies.
4Natural Resources Conservation Service, “The Heart of Soil: The Importance of Soil Health Principles”: An examination of healthy soil’s role in sustainable agriculture.
4Soil Science Society of America, “Soil Basics”: A deep dive into soil: what it is, it’s different types, and its function.
4Sustainable Agriculture Research and Education, ‘Why Soil Organic Matter Is So Important’: A comprehensive explanation of organic matter’s role as the foundation for healthy plants, animals, and humans.
Soil conservation contributes to sustainability and offers the following benefits:
4Improves soil quality and productivity. Increased fertility improves crop yields, reduces the need for chemical fertilizers, and saves money.
4Optimizes water infiltration. Better filtration increases water storage, preventing soil from drying out.
4Provides food and shelter. Soil-producing vegetation provides nourishment to all types of animals and offers protection from the elements.
Soil conservation also helps to minimize the following:
4Loss of fertile and arable land, impacting crops and livestock production, as well as the economy
4Pollution and sedimentation flowing in streams and rivers, affecting fish and other species
4Erosion and environmental degradation and desertification of land, potentially increasing flooding and negatively impacting forest ecosystems
Soil conservation is key to environmental sustainability. It helps protect natural resources and watersheds, restores habitats for plants and wildlife, improves water quality, and makes soil healthier. Soil conservation also creates economic opportunity. Productive and healthy soil helps farmers meet increased demand for agricultural commodities from a growing global population, driving economic growth. Tilling turns over about 10 inches of topsoil and allows farmers to plant more seeds with less effort. A downside of tilling is that it removes the plant covering, potentially leaving the soil bare, decreasing the amount of nutrient-rich organic matter, and reducing its ability to absorb water and retain nutrients. Tilling can also make the soil more susceptible to erosion. In no-till farming, seeds are planted in narrow furrows, eliminating the need to plow. No-till farming protects the soil from moisture loss due to high temperatures because cover crop residue remains on the surface of the soil. The residue layer also helps infiltrate water into the soil and increases organic matter and microorganisms, further enriching the soil.
Terrace farming is an agricultural practice that uses terraces, or steps, built into the slopes of hilly or mountainous areas to create a water catchment system for crops and is commonly used in growing rice. Rainwater carries nutrients and vegetation from one terrace to the next, so the soil remains healthy. Terrace farming also reduces soil erosion and improves soil productivity in otherwise idle plots of land.
Like terrace farming, contour farming involves growing crops on hills, but instead of changing the structure of a hill, the farmer uses its natural slope. In contour farming, a farmer plows the soil parallel to the hill’s contours, creating rows of small dams that minimize runoff of essential nutrients, organisms, and plants, while increasing water infiltration in the soil. The U.S. Department of Agriculture (USDA) reports that contour farming can reduce soil erosion by as much as 50 per cent.
Instead of planting the same crop year after year on the same plot of land, crop rotation involves planning out growing seasons for different crops. This method of sustainable agriculture requires long-term planning, with crops changed every season. In addition to improving soil health and organic matter, crop rotation reduces the need for fertilizer and pesticides, lowering costs. It also helps prevent excess chemicals from entering water supplies, improving water quality.
Windbreaks are rows of trees and bushes planted between fields of crops, reducing the erosive power of the wind on the soil. Windbreaks also provide homes for living things. From an economic standpoint, using trees that produce fruits and nuts in windbreaks can diversify farm income.
The U.S. Environmental Protection Agency (EPA) defines wetlands restoration and protection as “removing a threat or preventing the decline of wetland conditions.” Wetlands provide a habitat for living creatures of all types. They also act as buffers, protecting farmlands from floods. Like windbreaks, buffer strips are designated areas of land planted with trees and bushes. Instead of protecting soil from the wind, their purpose is to prevent water runoff and reduce erosion.
In areas where soil has degraded, the reestablishment of forest cover can improve soil and restore ecosystem health. This method provides shade for crops and is particularly useful for forest farming, which cultivates high-value crops, such as those used for medicinal purposes. Earthworms are among the most productive organisms in soil. They digest plant matter, releasing essential nutrients into the soil, and their tunnel networks create air channels that help water move through the soil.
Unsustainable agricultural practices can affect soil health, which in turn affects the global climate cycle. Poorly managed soil can release excess carbon dioxide, a greenhouse gas that contributes to climate change. Restoring degraded soil and using soil conservation practices in agriculture can effectively sequester carbon, helping build resilience to the effects of climate change. Soil conservation also promotes sustainable and economic development to meet the U.N. Sustainable Development Goals (SDGs): 17 goals focused on providing a “sustainable future for all.” According to the European Environment Agency, seven SDGs directly correlate to soil conservation practices, including SDG 6 – Clean Water and Sanitation: Through drainage and purification, soil helps to provide clean water for drinking and farming; SDG 13 – Climate Action: Through sequestration, soil can play a pivotal part in combating climate change by reducing atmospheric carbon and SDG 15 – Life on Land: Healthy soils are essential for sustainable management of forests, fighting desertification, and reversing land degradation. Building the resilience of our ecosystems is critical to addressing the challenges of a changing climate. One key factor sits right under our feet: soil. Through soil conservation, we can work to minimize the impact of climate change and support the long-term needs of society.
