In practice, the focus is often on how many nutrients are applied to a crop. But just as important is how much of those nutrients actually become available and are taken up by the plant.
That is exactly where fulvic acid plays an important role, the key component of our biostimulant NutriFul. Fulvic acid is a natural active substance extracted from deep Dutch groundwater, around 100 meters below the surface. Rather than acting as a fertiliser itself, fulvic acid works as an active component that influences processes in both the soil and the plant.
Fulvic acid is a carbon-rich, water-soluble, and highly biologically active fraction of humus. Thanks to its low molecular weight and reactive properties, it moves easily through the soil solution and interacts with minerals and organic compounds.
In the soil: improved mobilization of cations
In many soils, a significant amount of nutrients is present, but not directly available to the plant. This is especially true for cations such as calcium, magnesium, and trace elements, which are often bound to clay particles or organic complexes.
Fulvic acid influences these bindings by forming temporary complexes with these elements. As a result, cations become more mobile and available in the soil solution, exactly where plant roots can absorb them.
This effect has been clearly demonstrated in field trials. In a pear trial, where NutriFul was applied to the soil (2 × 10 l/ha), calcium uptake increased by 30% and magnesium uptake by 5%. Trace elements also increased significantly, especially iron (+66%) and manganese (+44%), but also zinc (+13%) and copper (+5%).
These results show that fulvic acid broadly improves nutrient efficiency, with a clear effect on both major nutrients and trace elements, particularly on the availability of cations.
Positive effect on phosphate availability
The effect of fulvic acid is not limited to cations alone. It can also positively influence phosphate availability, although through a different mechanism.
In soil, phosphate is quickly fixed. In calcareous soils it binds to calcium, while in acidic soils it forms complexes with iron and aluminum. As a result, part of the phosphate present in the soil becomes poorly available for plant uptake.
Fulvic acid can influence these fixation processes by binding to the elements that normally lock up phosphate. This helps phosphate remain available in the soil solution and accessible within the root zone.
Field trials also show this effect, where improved phosphate availability is linked to stronger root development and more efficient nutrient use.
In the plant: better efficiency and higher performance
Besides its effect in the soil, fulvic acid also plays a direct role when applied as a foliar treatment. Due to its small molecular structure, it can be absorbed through both the leaf cuticle and the stomata. Moisture conditions and contact time are important factors in this process.
Once absorbed, fulvic acid supports the transport of nutrients within the plant. This not only improves nutrient uptake, but also leads to visible improvements in yield and crop quality.
In an onion trial with foliar applications of NutriFul (3 × 1 l/ha), marketable yield increased by 4%, equivalent to approximately 2.5 tons per hectare. In addition, the grading shifted clearly toward the commercially preferred bulb sizes of 50–60 mm and 60–70 mm.
Nutrient efficiency also improved significantly: around 16 kg of extra yield was achieved per unit of nitrogen applied. The combination of higher yield, improved grading, and better efficiency resulted in a positive economic return of approximately €580 per hectare.
Stronger root development and crop growth
The influence of fulvic acid goes beyond nutrient uptake alone. By improving nutrient availability and transport, root system development is also stimulated.
This became very clear in a kiwi trial (1 × 20 l/ha soil application). Plant height increased by around 4%, while stem diameter increased by up to 25%.
The most striking effect, however, was measured below ground: root mass was up to 145% higher compared to the untreated control. NutriFul also showed clear improvements compared to a reference treatment, indicating a strong effect on root development and plant establishment.
From input to efficiency
The overall conclusion from these trials is that fulvic acid shifts the focus from input to efficiency. By releasing cations in the soil, supporting nutrient uptake through both leaves and roots, and improving nutrient transport within the plant, a system is created in which nutrients are used far more effectively.
Fulvic acid: from availability to utilization
Fulvic acid acts as an active link within the soil-plant system. It increases nutrient availability, especially cations, while also supporting nutrient uptake and internal transport within the plant.
What makes these results even more relevant is that the investment required is relatively limited. In practice, NutriFul application rates represent only a modest cost per hectare. Combined with improved nutrient efficiency, higher yields, and more effective nutrient use, this makes NutriFul not only agronomically valuable, but economically attractive as well.
Applications with NutriFul, containing 17% fulvic acid from a natural groundwater source, have consistently demonstrated improved nutrient efficiency, stronger root systems, and better overall crop performance. Want to know more? Please get in touch with us.
