Successful crop production relies on soil health. United Nations figures suggest one third of global cropland is degraded due to human impacts and another 18% is deteriorated through non-human factors (UNFAO State of Land and Water Resources for Food and Agriculture, 2021) at a time when soils are under pressure to produce more food with fewer resources.
Soil health is measured in terms of physical, chemical, and biological parameters. Physical traits include texture, structure, and stability. Chemical criteria include nutrient availability, cation exchange capacity, and pH. Biological characteristics are the amount of organic matter, as well as the diversity of micro-organisms and other soil dwellers. The three aspects of soil health interact.
Biostimulants are emerging as key contributors to improving soil health. Unlike traditional fertilisers, which provide essential nutrients directly to plants, biostimulants work by stimulating the natural processes within plants and the soil, which therefore supports soil health in the following ways:
Optimising Nutrient Use Efficiency
Biostimulants help plants utilise nutrients more efficiently, reducing the need for chemical fertilisers. By improving nutrient uptake and assimilation, they minimise nutrient runoff and leaching, which are common issues with conventional fertilisation practices. This not only enhances plant growth but also reduces the environmental impact of farming.
Improving Soil Structure
Certain biostimulants, particularly those containing humic and fulvic acids, enhance soil structure by promoting root development. When roots grow deeper and more extensively, they improve soil aeration and water retention. Additionally, the organic matter left behind by roots at harvest increases soil carbon content, further contributing to soil health.
Enhancing Soil Biodiversity
Microbial biostimulants play a vital role in fostering a diverse and healthy soil microbiome. These products introduce beneficial microorganisms that can fix nitrogen, solubilise phosphorus, and outcompete harmful pathogens. A rich microbial community is essential for nutrient cycling, soil fertility, and the overall resilience of the soil ecosystem.
Regulating Soil pH and Chemical Composition
Biostimulants can positively influence the chemical composition of soils, including regulating pH levels. A balanced soil pH is critical for the availability of nutrients to plants and the activity of soil microorganisms. By maintaining an optimal chemical environment, biostimulants contribute to healthier, more productive soils.
Mitigating Against Abiotic Stress
Biostimulants help plants cope with various abiotic stresses, such as drought, extreme temperatures, and salinity. By enhancing the plant’s natural defence mechanisms, biostimulants prevent crop failures that could lead to soil degradation. Maintaining crop cover through stressful conditions also helps prevent erosion and promotes water retention in the soil.
The role of biostimulants in soil health aligns with the goals of sustainable agriculture. As the agricultural sector faces increasing pressure to produce more food with fewer resources, biostimulants offer a pathway to achieving higher efficiency while preserving the natural environment. They support the EU’s Soil Health Observatory indicators, including soil carbon stock, biodiversity, and erosion control, making them integral to the future of farming.
Biostimulants are a powerful tool in the quest for healthier soils and more sustainable agricultural practices. By enhancing the natural processes within plants and soils, they contribute to long-term productivity and environmental protection, ensuring that our soils remain fertile and resilient for generations to come.