A climate full of extremes
Climate change has put increasing pressure on Flemish agriculture in recent years. Prolonged droughts, heat waves and unpredictable precipitation lead to yield losses and quality problems. Especially in northern Limburg, with its light sandy soils and high concentration of livestock farming, this translates into increased drought stress for crops. Although groundwater levels are relatively high in parts of the region, the upper soil layers, crucial for crop growth, dry out quickly. This makes crops on sandy soils especially vulnerable.
Grassland as a forward-looking crop
Grassland is the most common crop in Flanders and forms the basis of roughage production. In Limburg alone, it covers more than 32,000 hectares. At the same time, grass is highly dependent on sufficient precipitation and thus sensitive to drought. Yet grassland, especially in mixtures with clover and herbs, offers important opportunities in the light of stricter environmental legislation such as zero fertilisation and the Manure Decree.
Grass (clover) can still maintain basic production with minimal or no fertilisation. Leguminous plants such as clover fix nitrogen from the air, reducing the need for external inputs. In addition, grass absorbs nitrate quickly, which helps reduce leaching. Grassland also scores well in terms of climate: it can provide locally produced protein and thus (partly) replace imported soy, which is often linked to deforestation and a high carbon footprint.
Deep roots as key to drought resistance
The resilience of grassland to drought is largely determined by what happens underground. A deep and healthy root system allows water and nutrients to be absorbed from deeper soil layers when the top layer has dried out. Research from Wageningen University & Research shows that deeper roots can use significantly more water.
In addition, roots improve soil structure and feed soil life through root secretions. This stimulates micro-organisms, promotes nutrient availability and initiates a positive, regenerative cycle leading to a more resilient soil system.
Factors affecting rooting
The rooting depth of grass is determined by several factors:
- Species and variety selection: deep-rooting species such as reed fescue and alfalfa are more resistant to drought.
- Soil structure: compaction by heavy machinery limits root growth and water infiltration.
- Chemical soil quality: pH and nutrient ratios affect the uptake of essential elements.
- Soil biology: micro-organisms and earthworms improve structure, nutrient cycling and root access to deeper layers.
The importance of fertilisation and manure management
Fertilisation choices have a direct impact on root development. Fertilisers provide rapidly available nutrients, but require a lot of water and energy from the plant and can cause additional stress under dry conditions. Organic fertilisers, such as slurry, work more slowly and support soil life and structure.
Within DeepRoot, the focus is on slurry, as this product is widely available but can vary greatly in composition. Factors such as feeding regime and manure basement management help determine how slurry affects soil and root growth. Thoughtful application can enhance rooting and thus increase drought tolerance.
Purpose of the DeepRoot project
DeepRoot aims to future-proof grassland by focusing on a robust and deep root system. Through practical trials, fertilisation, soil conditioners, seed mixtures and soil treatments are evaluated. Here, grassland serves as an ideal testable crop thanks to its perennial nature and rapid response to management measures.
DeepRoot's four core ambitions:
- Demonstrating the relationship between fertilisation and root depth
- Supporting farmers in thoughtful fertilisation and management choices
- Promoting root growth through better soil management and reducing compaction
- Using grassland as field crop for research on rooting and drought tolerance
DeepRoot is building an agricultural system that is less dependent on irrigation and external inputs, and more resilient to climate change. By putting natural soil and plant processes at the centre, the project contributes to a sustainable, economically viable and climate-adaptive agricultural model.
