Exploring the Link Between Soil Quality and Nutrient Density
Written by Sophie Kirk, Deakin University Food & Nutrition Science Placement Student
The nutritional density in our global produce has declined significantly within the past 50-70 years. (1) Whilst yields have gone up and soil health has been neglected more and more in modern day farming practices, nutrient levels in commercial produce have suffered. (2) So how exactly does sustainable agriculture and soil quality contribute to nutrient density, and why is this important?
Nutrient density is the concentration of essential nutrients in a weight of food, relative to its caloric content. Nutrient dense foods provide high levels of vitamins, minerals and beneficial compounds. This impacts dietary quality directly - a diet rich in nutrients gives our bodies the fuel to support all of its essential processes and functions.
Soil acts as the foundation of agriculture, providing essential water and nutrients for the plants that grow within it. It’s made up of a complex mix of minerals, organic matter, water, and air, which all influence key factors for crop health like water retention, drainage and microbial activity. (2)
Whilst the inherent genetic makeup of a plant strongly determines its nutritional content, the growing conditions and soil quality also play a key role. Optimal growing conditions increase photosynthesis and the synthesizing of nutrients. Droughts or extreme temperatures can cause stress to plants, negatively impacting their nutrient levels, which is why it’s important the soil in which they grow is healthy and resilient. (3)
What makes soil ‘healthy’ and ‘resilient’? Key components of healthy soil include strong soil structure, organic matter and biodiversity. (3)(4)
The structure of the soil affects the aeration, water infiltration and root penetration of the soil (meaning the roots can more easily access nutrients). This ensures more resilient soil that is less affected by changes in climate.
Organic matter includes decomposed plant and animal materials, which improves the water retention and fertility of the soil. It ensures the plants get essential nutrients, enhances the structure of the soil and supports microbial life - contributing to nutrient cycling.
Biodiversity means having a diverse community of organisms within the soil - such as bacteria, fungi and more microorganisms. This maintains soil health and contributes to soil aeration and nutrient composition. Microorganisms break down organic matter from decomposed plants and animals, which releases nutrients back into the soil (such as nitrogen, phosphorus and potassium). For example, bacteria convert ammonium into nitrate, a form readily available to plants, and fungi enhance nutrient absorption through symbiotic relationships with plant roots, making nutrients more accessible. (3)(4)
The connection between soil health and nutrient density emphasises the importance of nurturing our agricultural ecosystems. This is why practices like regenerative farming, implemented here at Common Ground Project, are fundamental. It’s no wonder, reflecting back to an interview we did with Tony from Resilience Farming, the use of a refractometer revealed that the produce from CGP had a nutrient density 20-40% higher than that of commercially grown options.
Healthy soils are essential for producing nutrient-rich crops, which directly impact human health and well-being. By understanding this relationship and supporting practices that enhance soil health, we can improve food quality, contribute to better public health outcomes, and support a stronger food system.
References
Bhardwaj, R.L. et al. (2024) ‘An alarming decline in the nutritional quality of foods: The biggest challenge for Future Generations’ Health’, Foods, 13(6), p. 877. doi:10.3390/foods13060877.
Why modern food lost its nutrients - BBC News. Available at: https://www.bbc.com/future/bespoke/follow-the-food/why-modern-food-lost-its-nutrients/
Montgomery, D.R. and Biklé, A. (2021) ‘Soil Health and nutrient density: Beyond organic vs. conventional farming’, Frontiers in Sustainable Food Systems, 5. doi:10.3389/fsufs.2021.699147.
Vegetable systems trial (2024) Rodale Institute. Available at: https://rodaleinstitute.org/science/vegetable-systems-trial/
