Soil health

Summary

Soils are the foundation of agriculture and our food system. Soil health and vitality are pre-requisites for robust crop production and a sustainable future for farming.

Yara takes a long-term view on soil health. By providing farmers with tools and services enabling precise and balanced nutrient management in combination with suitable fertilizer products, we help them preserve and improve the fertility and health of their soils.

Download our position paper on Soil Health

The importance of soils

Soils are the foundation of agriculture and our food system. Soil health and vitality are pre-requisites for robust crop production and a sustainable future for farming.

Comprised of minerals, organic matter, air, water and living organisms, soils provide a rooting medium and nutrient source for plants. Soils contain a wealth of biodiversity and play a key role in regulating, storing and filtering water. Additionally, because of their ability to store carbon, soils play an important role in climate change mitigation.

Soil quality or soil fertility typically refers to the ecosystem services soils provide, such as adequate crop yields. Soil health, in a broader sense, emphasizes the role of soil as a living ecosystem that sustain the wellbeing of animals, people and the planet. It is this broad definition of soil health that Yara bases its work to improve and maintain soil health and vitality.

Soils are being degraded

An estimated one-third of agricultural soils are degraded1 which leads to agricultural productivity losses, reduced water holding capacity and a decreased ability for the soil to capture carbon. The degradation of soils is a risk for food production globally and subsequently, a threat to food security.

Soil degradation occurs due to a variety of both natural and human-induced processes. The most significant threats to soil function at global scale include soil erosion, loss of soil organic carbon, soil nutrient mining and nutrient imbalance, acidification, salinization and sodification.1, 2 With the pace of soil erosion drastically exceeding the pace of soil formation,3 we see an urgent need for soil preservation and the restoration of degraded soils. When combined with other threats to soil health (climate change, imbalanced nutrient and carbon flows combined with growing demand for food), it is imperative that we act to prevent a severe impact on food supply.

Sustainable cropland management, sometimes referred to as conservation agriculture, regenerative agriculture or good agricultural practice, aims at improving soil health and the proper functioning of the wider agro-ecosystem.
Practices can include a variety of methods, such as crop rotations, use of cover crops, reduced tillage, optimized nutrient applications incorporating organic fertilizers and balanced use of mineral fertilizers, liming and prevention of soil compaction. Applying these practices over time will likely maintain and improve soil health, depending on location- and condition-specific contexts. The United Nations Global Compact’s Principles for Sustainable Soil Management4 provides a helpful framework for good soil management, stewardship and policymaking.

The vital role of balanced crop nutrition

Best practice crop nutrition management, ensuring balanced fertilization suited for local conditions, is at the core of all good agricultural practices.

When crops are harvested, nutrients are removed from the soil. If these nutrients are not replaced, soil health will decline and eventually lead to soil degradation. Applying adequate amounts of organic biomass and required nutrients, in the form of organic or mineral fertilizers, maintains or increases crop growth, which in turn provides for larger quantities of crop residues to be returned to the soil. It contributes to the nutrition of soil organisms and the improvement of soil organic matter content and soil carbon sequestration.

When assessing soil carbon contents, it is important to consider that soil organic carbon levels and soil health are not necessarily correlated. A high level of soil organic carbon on its own is not a reliable indicator of soil health.

In addition to the major nutrients – nitrogen, phosphorus and potash – crops ultimately need a total of 13 different nutrients to obtain optimal yield and quality. Without a balanced approach to manage all plant nutrients, soils will become degraded. This is illustrated by the “Law of the Minimum” (Liebig, 1843) which states that “crop yields are proportional to the amount of the most limiting nutrient”.

Soil acidification is a major concern of soil health. The application of nutrients come with a specific requirement of lime and this needs to be managed to avoid soil acidification. In case this is not managed properly, soil health can suffer, and soil can become too acid for crop and soil life. As the importance of liming is widely known, it is addressed in common advisory systems.

Nutrient applications to farmland that exceed the nutrient demand of the agricultural crops can harm water quality and marine ecosystems and may lead to increased greenhouse gas emissions. Soil health is less sensitive to nutrient oversupply and many soils benefit from a nutrient accumulation up to a certain level.

The challenge of defining, measuring and monitoring soil health

Soils are living ecosystems characterized by varying natural states. They are in constant change and some level of degradation occurs naturally, without human intervention. Due to the variability and constant evolution of soils, an all-encompassing and scientifically standardized framework to define a “healthy soil”, does not yet exist. There are various ongoing initiatives aiming to establish standardization methods to evaluate and monitor soil health, such as Yara’s Soil Health Report that is being developed in Pocklington, United Kingdom.

The importance of an enabling policy environment

Due to the complex cross-sectorial, and often site-specific, nature of soil and land management, national, regional and global level policies and regulations tend to be fragmented. The exception is the United Nations Convention to Combat Desertification (UNCCD) 2018 – 2030 Strategic Framework, which sets global commitments to achieve Land Degradation Neutrality (LDN). This provision is currently the sole legally binding international agreement that links environment and development with the promotion of healthy soils.

Achieving the goals set forth in the LDN requires a policy environment in which various regulatory bodies coordinate policy on cross-cutting soil issues (agriculture, water, waste, pollution, food security and safety) in close association with farmers, scientists and the private sector. In addition, farmers require better access to knowledge, tools and financial incentives to stimulate an effective delivery of enhanced soil ecosystem services.