TECHNOLOGY FOCUS - AGRICULTURE - Preferred Process: The composition is treated at 170-230degreesC a bi-screw extruder (1). The extraction step is: carried out at 40-150degreesC, preferably 120degreesC by treating the humic substances with an alkaline solution, mixing the obtained intermediate product with the alkaline solution and recovering a liquid phase comprising the artificial humic substances and lowering the pH of the liquid phase; or carried out by macerating the intermediate product with the alkaline solution under agitation and subjecting the obtained product for solid-liquid separation process by filtration. The steps of extraction process are using a bi-screw extruder (7). The bi-screw extruder contains: an upstream zone, where the heat and/or the mechanical treatments are taken place; and a downstream zone in which the intermediate product of the upstream zone is put in contact with the alkaline solution. The downstream zone also comprises an opening of evacuation of liquid equipped with a solid-liquid filter to carry out solid-liquid separation by filtration. The process comprises adding a nitric acid solution to the liquid phase at a concentration and quantity to obtain a liquid solution of pH compatible to be used as manure to fertilize grounds of culture. Preferred Composition: The composition comprises the lignocellulosic matter at less than 20%. The composition comprises of poplar wood in powdered form at a thickness of less than 1.5 cm. The composition is present in liquid form. Preferred Components: The lignocellulosic matter is wood, stems and raids of corn or cereal straw. The wood particles of poplar are in the form of slices or sawdust.    TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - The alkaline solution is potassium hydroxide that is present at a normality of 1N. The concentration of the nitric acid is 1N.    TECHNOLOGY FOCUS - INSTRUMENTATION AND TESTING - Preferred Components: The extruder comprises the heated enclosure, which allows to bring the lignocellulosic matter up to the temperature of the treatment; rotators (2a, 2b) and their screw provides mixing and crushing effect. The bi-screw extruder comprises an enclosure (10) to receive the intermediate product, a solid-liquid filter (13) installed at a downstream end of the enclosure and rotators (9a, 9b) and their screw provides the malaxation or maceration step. EXAMPLE - Wood chips were dried at 100degreesC in a drying oven until a water content of 7% was reached in the wood chips composition. The obtained chips were introduced at a flow rate of 4.5 kg/hour in a standard bi-screw extruder to give the composition.