A complex ecosystem lives in the soil beneath your feet. There’s much more to it than mud. In fact, the earth we walk upon is crucial to the resilience of our food systems and the health of our environment. And we need to take much better care of it.
Here Giulia Stellari, Unilever’s Sustainable Sourcing Director, explains why – and how – Unilever is taking action to protect soil.
What’s at risk if we don’t look after soil?
It’s no exaggeration to say soil is essential to life on Earth. It’s the medium through which plants and the people and animals who eat them receive their nutrition. It helps to regulate the planet’s water cycles, holding and releasing water throughout the year. And it’s the habitat for many animals from prairie dogs to worms, as well as fungi and bacteria.
Soil is alive and wonderfully complex. If we don’t look after soil, we put the balance of all the agroecosystems which rely on it at risk.
What role does this biodiversity play in keeping soil healthy?
Soil comprises mainly living organisms or the remains of dead organisms. If fact, there are more micro-organisms in a teaspoon of soil than there are human beings on the planet. These are principally the myriad of bacteria, fungi and other single-cell organisms that make up the bulk of soil. This is a good thing because these organisms help to release nutrients from the soil so that they can travel into the plants and nourish them.
Soil biodiversity is still poorly understood. We know that the amount of biodiversity in the soil is an important factor in soil health, but scientists are still working on how this interacts with the plants that grow in the soil, and how we translate that into overall soil health.
What contributes to soil erosion and damage?
We have to remember that soil itself is partly the product of erosion – the slow weathering of large rocks to form silt and sand which make up the inorganic part of soils. So not all erosion is bad. The bad kind of erosion comes from practices that change the quality of the soil or the amount of soil that is present.
The worst forms of erosion happen when areas of forest are cleared on hillsides or mountain slopes. When the soil is no longer held together by the roots of trees and bushes, rainy weather can cause massive mud slides, resulting in devastating damage and the loss of huge amounts of topsoil.
Soil is also vulnerable to erosion in the winter when plant roots are not available to hold it in place and harsh weather can wash away the top layers. Over the years this can decrease the amount of soil that is present on a farm. Without deep rich soils, plants are not as resilient, needing more water and more fertiliser to grow.
Attempting to prepare soil too soon in the season, or running heavy machinery or equipment on soil when it is too wet, can cause irreparable damage too. Air is pushed out of the soil and the soil becomes dense. This compaction makes it difficult for plants to grow because their roots are unable to penetrate the soil or easily get the oxygen they need to grow.
How is Unilever supporting farmers to use practices that protect soil?
All agricultural suppliers work to the rigorous standards set out in our Sustainable Agricultural Code (PDF 7.67MB). We are now also working with suppliers to apply regenerative agricultural practices, which farmers can adopt to leave a positive impact on soil health.
One of our largest programmes focusing on soil health is in the soy supply chain for Hellmann’s in Iowa. We’ve been working closely with soy farmers and soy oil suppliers to introduce the use of cover crops as a way of protecting the soil to prevent erosion.
A combination of droughts and heavy rainfall over several years has seen Iowa’s nutrient-rich soils degrade and decline. The soils are washed off, and the nutrient-rich run-off flows into the Gulf of Mexico via the Mississippi River. This is bad news for Iowa farmers and for the environment and downstream communities affected by this issue.
Planting cover crops between harvests, rather than leaving the earth bare, can help prevent erosion and the loss of nutrients by keeping roots in the ground all year.
How are you scaling this up?
Each year we have recruited more and more farmers into this programme via on-the-ground engagement through our partner, Practical Farmers of Iowa.
We’re working with the local farming community and our network of suppliers to share the programme with farmers, using peer learning as a way to build confidence in trying cover crops. This includes learning events and field days – all designed to connect local farmers so they can share knowledge to build healthy soils.
For those who are new to the practice, we have a special programme that further mitigates the risk of testing cover crops for the first time. This approach has proved very successful for recruiting new farmers and is expected to play a key role in scaling up the programme. Our goal is to ensure every acre of land used to grow soy for the production of our Hellmann’s mayonnaise is covered, and the soil protected.
What are some of the actions we can all take to make a more positive impact on soil health?
Choosing to eat a more diverse diet is a great step. If we start eating a wide range of different grains such as spelt, quinoa or buckwheat, or vegetables such as cabbage, kale and spinach, we can influence farmers to increase the variety of crops they choose to grow.
Not only does that make our food systems more resilient, it’s also better for the soil and the billions of micro-organisms that live within it too.