Biostimulants based on water-soluble concentrated humic acid extracts of leonardite/Lignite and aquatic fulvic acids are already used worldwide as biostimulants in adverse climatic and soil conditions for the purpose of climate-adapted agriculture. Climate-related abiotic stress factors include heat, drought and salt stress, but also wetness, frost and cold. Humic-based biostimulants such as humic and fulvic acids serve to increase the tolerance of crops to these abiotic stress factors. For example, humic and fulvic acids are able to decisively reduce the salt concentrations in the soil solution through their adsorption capacity and thus enable higher-yielding agriculture again via the lower salt-induced osmotic pressure on the plants.
At the same time, humic and fulvic acid-based biostimulants increase the fertilisation efficiency of macronutrients such as phosphorus, nitrogen and potassium. Especially for the plant-available mobilisation of mineral fixed phosphates, humic substances play a decisive role in the soil. In addition, humic substances mobilise essential trace nutrients such as iron, zinc, copper and manganese, which otherwise cannot be directly absorbed by crops, especially in dry soils poor in humus.
The complexation of these trace nutrients by natural humic acids is an excellent alternative to persistent synthetic chelates such as EDTA. The adsorption of ammonium nitrogen by humic substances reduces emissions of the greenhouse gas ammonia from farm manures such as slurry and digestate, while at the same time helping to reduce nitrification and thus nitrate inputs into groundwater.