Overview
- Introduction to soil health
- The functions of soil health
- Why is soil health important?
- What is soil degradation?
- How can we protect soil health?
- The role of organic matter in soil health
- The importance of organic matter and biodiversity in soil
- The impact of soil structure on water regulation and plant growth
- Soil health and climate change
- The future of soil health: Innovations and strategies
Introduction to soil health
Soil health is the capacity of soil to function as a vital living ecosystem that sustains its functions. Soil is a complex environment with many components, including organic matter, communities of micro-organisms (microbes), air and water pores, and minerals.
Sadly, human activities can damage soil health impacting entire ecosystems. However, some agricultural practices, such as regenerative farming, or integrated pest management, can help protect and restore soil, so it can maintain its vital functions.
In this article we explore soil health, why it is important, how to improve it and future strategies.
The functions of soil health
Healthy soil sustains essential functions such as:
- Water regulation: stores water and regulates movement.
- Support for plant and animal life: contributes to biodiversity and productivity of living organisms.
- Pollutant filtering: minerals and soil microbes filtrate pollutants, which protect groundwater quality.
- Nutrient cycling: soil microbes participate in the storage and cycling of nutrients like phosphorus, nitrogen and carbon.
- Physical stability and support: acts as a medium for plants to grow in and support human construction.
Understanding the physical, chemical, and biological aspects of a healthy soil
Soil health is a combination of three main soil properties:
- Physical properties: visual indicators, which include soil structure, aggregate stability, crusting and compaction, permeability, texture, porosity, etc.
- Chemical properties: they represent the chemical processes happening in the soil, for instance, nutrient availability, pH, salinity, etc.
- Biological properties: include visual indicators such as macro-organisms like earthworms, collembola, mites, etc. and their activity and byproducts.
All these aspects interact dynamically and can foster healthy soil together. For instance, soil structure influences water retention, which creates a good environment for microorganisms.
Why is soil health important?
Soil is the foundation of agriculture and sustains life on earth by providing nutrients, clean air and water. Healthy soil helps produce robust plants, increasing crop yields, food production and food security. Heathy soil also stores carbon from the atmosphere, mitigating climate change.
Unfortunately, soil health is under threat worldwide due to several drivers, including intensive agriculture, deforestation, erosion, pollution, and improper fertilizer and application. A recent study estimates that 61% of lands in the European Union are affected by soil degradation, while globally, the FAO reports that 33% of soils are already degraded. In addition, the IPBES states that over 90% of soils could become degraded by 2050.
The consequences of soil degradation and poor soil health go well beyond the loss of good soil for farming. They affect various aspects of human well-being and the environment. For instance, as degraded soil holds less water, it can decrease the amount of water available for plants and worsen drought.
What is soil degradation?
Soil degradation is the physical, chemical and biological decline in soil quality, which can be caused by human activities or natural processes. Factors influencing soil degradation include:
- Soil compaction by heavy farm machinery, excessive tillage and leaving the soil bare. Compacted soil does not have enough space for the movement of air, water and plant roots.
- Soil erosion or the loss of the top layer of soil at a rate faster than it is formed. This layer is the fertile portion of soil and is essential for plant growth. Erosion is mainly due to soil being exposed to climatic conditions after tillage and deforestation. Soil erosion can also increase pollution in water bodies.
- Chemical pollution from pesticides, fertilizers and other industrial chemicals. This negatively impacts soil microbes, decreases the amount and diversity of soil organisms, and reduces soil fertility.
- Tillage that releases carbon into the atmosphere, contributing to the emissions of greenhouse gases and causing poor health of soil. Overall, this contributes to climate change.
As a result of soil degradation, soil quality gets poorer in nutrients and loses its capacity to hold water. This causes food production to decrease; in the worst cases, degraded soil cannot support plant growth anymore.
We must protect soil health at all costs so that soils can sustain its functions, safeguarding the environment and human well-being.
How can we protect soil health?
Maintaining or creating healthy soil has many benefits. See some of our recommended techniques, supported by science, to protect this vital life source for both commercial and private lands.
How to improve soil health for gardening
You can promote soil health at home in your own garden by:
- Creating compost from food waste, grass clipping or plant debris, for instance. In doing so, you can avoid the overuse of chemical fertilizers.
- Mulching increases the soil organic matter and promotes the activity of soil microbes.
- Using biological control are nature-based environmentally-friendly products that protect your garden from pests and diseases and improve plant health.
Agricultural practices to promote soil health
Whilst agriculture is a driver of soil health decline, there are several agricultural practices that can reverse the trend and help restore soil health. Following these, growers can:
- Reduce the use of chemicals by opting for nature-based solutions like biocontrol and bioprotection products, which have many advantages. These natural products are safer for non-target organisms and preserve soil biodiversity.
- Increase the amount of organic matter going back into the fields with a cover crop by leaving crop residues on the soil surface or using organic mulch.
- Reduce soil compaction from machinery and livestock through minimum or zero tillage and pasture management to avoid over-grazing. This minimizes soil disturbance, which helps build back soil health.
- Rotate crops to increase diversity above and within soil to break the cycle of pests and diseases. Legumes are good crops for rotation as they increase nitrogen in the soil.
- Learn more about regenerative agriculture and its benefits in our blog ‘Regenerative agriculture: an approach to tackle food security issues.’
Other ways to improve soil health in a farming system are:
- Managing water by planting vegetation such as trees and shrubs. It can increase the infiltration of water into the soil. Other techniques, like mulching, help save water.
- Managing nutrients by carefully planning and applying manure and fertilizers to minimize nutrient excesses.
- Integrated Pest Management to tackle pests sustainably. This limits unwanted environmental effects.
- Read more about IPM in our blog ‘Integrated Pest Management: how it works and benefits‘
The role of organic matter in soil health
Organic matter is any material produced originally by living organisms (plants and animals) and is returned to the soil for further decomposition.
Rich soil with organic matter has biodiversity, like bacteria, viruses and fungi, but also macro-organisms such as beneficial insects or worms.
The presence of organic matter in soil is essential as a source of nutrients for macro- and microbial organisms. These organisms break down nutrients that are absorbed by plants.
The importance of organic matter and biodiversity in soil
Organic matter helps soil to function and influences it, directly and indirectly, in many ways, such as:
- Improving soil structure
- Regulating soil pH, temperature and aeration
- Promoting microbial activity and diversity
- Supplies nutrients essential for plant growth
- Enhancing disease suppression
- Enhancing water absorption and retention
- Reducing soil erosion, avoiding the loss of fertile lands.
Organic matter is therefore vital for enhancing overall soil health and fertility and increasing soil biodiversity. Likely, soil biodiversity is essential for the cycling of nutrients and water as well as pest suppression, all of which support plant growth and health. In other words, soil biodiversity provides us with food and clean water.
The dynamics between organic matter and nutrient cycling
Organic matter is a reservoir of nutrients that are slowly released into the soil through its decomposition over time. Microbial organisms decompose organic matter to break down these essential nutrients into a form that plants can absorb. As a result, soil fertility increases, and plants can grow better and stronger. Proper management of organic matter ensures a balanced nutrient cycle. This will contribute to long-term crop productivity and a balanced ecosystem.
From composting to mulching: Practical approaches to increase soil organic matter
Several practical approaches increase soil organic matter in gardening and agricultural systems. Two ways to do this are via:
- Composting: once fully decomposed, compost becomes organic matter full of nutrients that can return to the soil.
- Mulching: by applying any material to the soil to cover it. Wood chips, shavings, bark or plant residues can be used. As the mulch covers the soil surface, the soil retains moisture more effectively, weeds have more difficulty germinating and growing, and soil microbial flora increases.
The impact of soil structure on water regulation and plant growth
Soil structure is a fundamental aspect of soil health, directly influencing its ability to regulate water and support plant growth.
Soil structure refers to the aggregates of soil particles and pores (or spaces) between them. A well-structured, healthy soil has large pore spaces that allow water to penetrate the soil rather than run off it, air to circulate better, and plant root to reach nutrients and water more effectively.
On the contrary, compacted or poorly structured soil restricts water movement and root growth, leading to reduced plant growth. Over time, these factors contribute to soil degradation, further diminishing soil health.
Soil health and climate change
Soil health and climate change are intricately linked. Climate change affects soils through extreme weather events, higher temperatures, or changes in precipitation patterns, to name a few. These impact soil health in many ways. For instance:
- Reduced amount of organic matter from a high rate of decomposition
- Disturbed soil structure
- Reduced soil moisture due to high temperatures
- Increased erosion
Soil health also profoundly impacts climate. Healthy soil can absorb carbon from the atmosphere (CO2) through carbon sequestration and store it in the soil, eventually limiting greenhouse gas emissions. However, unhealthy soil contributes to the emission of CO2 or methane into the atmosphere in several ways, including the loss of organic matter. Unhealthy soil also sequesters less carbon, aggravating the impact of climate change.
Therefore, good soil health is one vital part of helping tackle climate change.
The future of soil health: innovations and strategies
Given the importance of maintaining soil health, advances in technology give an opportunity to utilize these new mediums to help monitor, record and protect soil.
Technological advances in soil health assessment and management
Additionally, precision agriculture and smart technologies are starting to transform how farming systems are managed. In terms of soil health, tools such as soil sensors, drones, and satellite imagery can collect lots of soil variables that can support farmers in making informed decisions.
Measurable soil variables include, for instance, moisture levels, soil pH, and nutrient content. Information from these measures can help adjust irrigation schedules, optimize fertilizer application, and more. These technologies are not only improving crop yields but also promoting soil conservation and long-term health.
US policy
A promising development is the recent introduction of US policy to protect soil health, promoting sustainable agricultural practices to improve food security and combat climate change. Policymakers are introducing laws to promote soil health at the federal and state levels.
For instance, the USDA’s Natural Resources Conservation Service (NRCS) has several programmes that provide technical and financial assistance to farmers and landowners in implementing conservation practices that improve soil health.
The 2018 Farm Bill, extended in 2023, is one of the country’s most significant funding in the conservation and management of farmlands. It provides programmes that support healthy soil practices.
Global movement towards soil health and sustainability
Soil health is increasingly recognized as a cornerstone of sustainability. There is a growing movement towards prioritizing soil health through practices such as regenerative agriculture, agroecology and climate-smart agriculture. Global initiatives, such as the United Nations’ Sustainable Development Goals (SDGs) and the Global Soil Partnership, emphasize the critical role of healthy soil in achieving food security and tackling climate change.
Countries worldwide are adopting policies and practices that promote soil conservation. Collaborative efforts among governments, NGOs, and the private sector are driving research, education, and the implementation of sustainable soil management techniques, fostering a global commitment to preserving and enhancing soil health.
By embracing these sustainable practices and fostering global cooperation, we can ensure that our soil continues to support life, safeguard the environment, and provide food security for generations to come.
FAQs
What is meant by soil health?
Soil health is the ability to function as a living ecosystem in a particular environment as needed to maintain plant, animal and human life.
Healthy soil helps with water regulation, supports animal and plant life, filters pollutants, cycles nutrients, provides physical support and more.
What is in healthy soil?
Healthy soil has many features, including an abundance of beneficial organisms like microbes, organic matter and minerals. Microbes such as bacteria and fungi decompose organic matter, transforming it into nutrients available to plants and filtrate pollutants. Minerals ensure proper drainage and aeration of the soil. Healthy soil also has a good structure and permeability. All components of soil, physical, chemical and biological properties must be maintained for good health.
How do you check soil health?
There are many ways soil health can be tested, depending on what information is needed and how the soil is used (e.g. for commercial purposes or in a private residence).
As a starting point, a simple soil science analysis is the first step. It measures nutrient levels, pH, and organic matter content, for example. To do this, take a soil sample from different locations in the area and send this to a soil laboratory for analysis. Alternatively, you can use visual soil assessments and DIY methods for checking soil health, including earthworm sampling, soil acidity, or alkalinity testing, and soil component assessment with an empty jar and water.
To fully assess soil health, it is useful to know the physical, chemical and biological properties. Understanding these will enable an assessment of the soil’s status, and what is needed to optimize functionality. Ideally, this will be done using different tactics to validate findings.
