Liquid biostimulant for plant growth.

Abstract

Title of the invention: Liquid biostimulant for plant growth. The present invention relates to a liquid biostimulant comprising at least a mass percentage of humic substances of between 2% and 20%, a mass percentage of extract of at least one alga of between 2% and 20%, and a vermicompost extract comprising at least one strain of bacteria of the genus Bacillus, at least one strain of bacteria of the genus Azotobacter, and at least one strain of bacteria of the genus Rhizobium. (Figure 1)

Description

Title of the invention: Liquid biostimulant for plant growth.

[0001] The present invention relates to a biostimulant used as a plant growth stimulant, particularly in agriculture. More particularly, the present invention relates to such a biostimulant obtained from vermicompost.

[0002] Biostimulants are commonly used inputs, particularly in so-called "conventional" and "organic" agriculture, to improve crop quality and yields. Today, in a context of developing new production methods, new inputs are being sought to promote crop yields while improving soil quality and biodiversity, using inputs that meet, in particular, the criteria of organic farming, while ensuring optimal yields.

[0003] Some existing inputs provide crops with the mineral elements necessary for their growth. However, such products do not meet all the constraints to which plants are subjected. Indeed, such inputs are not suitable for ensuring, in particular, fungal protection, protection against water stress, the promotion of symbioses between microorganisms and plants, or for making available the mineral elements naturally present in the soil.

[0004] As a result, farmers must increase inputs and spreading to provide their crops with the best conditions for development in order to promote both yields and biodiversity on their plots.

[0005] The present invention falls within this context and aims to overcome at least some of the drawbacks of the prior art. In particular, the present invention aims to provide a liquid biostimulant suitable for all types of agriculture, but also compliant with the requirements of organic farming and enabling it to effectively address the various stresses that plants experience during their growth.

[0006] Thus, the present invention relates to a liquid biostimulant comprising at least a mass percentage of humic substances of between 2% and 20%, a mass percentage of extract of at least one alga of between 2% and 20% and an extract of vermicompost comprising at least one strain of bacteria of the genus Bacillus, at least one strain of bacteria of the genus Azotobacter and at least one strain of bacteria of the genus Rhizobium.

[0007] The biostimulant is suitable for increasing soil microbial biomass. On the one hand, by supplying complex polysaccharides and amino acids derived in particular from the extract of at least one alga. On the other hand, by supplying microbial biomass. derived from vermicompost extract. It should be noted that the supply of complex polysaccharides and amino acids can also come, in addition to the extract of at least one algae, from plant extracts.

[0008] This composition makes it possible to facilitate the formation of symbioses between the plant and microorganisms, to degrade and mineralize organic matter efficiently and / or to solubilize nutrients confined in the soil.

[0009] Furthermore, the microorganisms present in the liquid biostimulant contribute to increasing the biomass at the base of the food chain. This increase in the biomass of the first links in the food chain contributes to increasing the biomass of later links, such as, by way of illustration and not limitation of the invention, fungivorous or insectivorous animals, at the plant level. The increase in the microfauna of the later links thus helps to regulate pests and diseases.

[0010] Furthermore, the high content of humic substances, particularly from the vermicompost extract, will have a strong effect on the physicochemical properties of the soil in order to optimize the mobilization of soil nutrients, whether they are already present and confined or supplied by fertilization programs.

[0011] According to one feature of the invention, the liquid biostimulant comprises a mass percentage of vermicompost extract of between 10% and 80%.

[0012] According to one feature of the invention, the liquid biostimulant comprises a mass percentage of vermicompost extract of between 40% and 70%.

[0013] According to a feature of the invention, the mass percentage of humic substances is between 5% and 15%.

[0014] According to one feature of the invention, the mass percentage of the extract of at least one algae is between 5% and 15%.

[0015] According to one feature of the invention, the extract of at least one alga is obtained from algae from the class Phaeophyceae.

[0016] According to one feature of the invention, the extract of at least one alga is obtained from algae from the Laminariales family.

[0017] According to one feature of the invention, the liquid biostimulant comprises a mass percentage of potassium between 0.1% and 5%.

[0018] According to one feature of the invention, the liquid biostimulant comprises a mass percentage of nitrogen between 0.05% and 5%.

[0019] According to one feature of the invention, the liquid biostimulant comprises a mass percentage of amino acids between 0.05% and 5%.

[0020] According to one feature of the invention, the mass percentage of amino acids is between 0.5% and 3%.

[0021] According to one feature of the invention, the liquid biostimulant comprises a mass percentage of phosphorus between 0.01% and 0.5%.

[0022] According to one feature of the invention, the liquid biostimulant comprises a mass percentage of sucrose between 0.1% and 10%.

[0023] According to one feature of the invention, the liquid biostimulant comprises a mass percentage of molasses between 5% and 15%.

[0024] According to one feature of the invention, the liquid biostimulant comprises a mass percentage of xanthan gum between 0.05% and 0.2%.

[0025] According to one feature of the invention, the liquid biostimulant comprises a mass percentage of phenylpropanoids between 0.05% and 0.5%.

[0026] According to one feature of the invention, the liquid biostimulant comprises a mass percentage of solvent made up to 100%.

[0027] According to one feature of the invention, the major solvent is water.

[0028] According to one feature of the invention, the liquid biostimulant comprises a pH between 2 and 12.

[0029] According to a feature of the invention, the liquid biostimulant comprises a pH between 3 and 5.

[0030] According to another feature of the invention, the liquid biostimulant comprises a pH between 6 and 8.

[0031] According to another feature of the invention, the liquid biostimulant comprises a pH between 8 and 12.

[0032] The invention also relates to the use of a liquid biostimulant conforming to at least one of the characteristics previously mentioned for soil treatment.

[0033] According to one feature of the invention, the liquid biostimulant is applied at a dosage of between 1 and 30 liters per hectare. Preferably, the liquid biostimulant is applied at a dosage of between 2 and 10 liters per hectare. More preferably, the liquid biostimulant is applied at a dosage of between 3 and 5 liters per hectare. The liquid biostimulant can be applied from one to four times during the growing cycle.

[0034] According to one feature of the invention, the liquid biostimulant is used within a fertigation installation.

[0035] According to another feature of the invention, the liquid biostimulant is used to make a praline. This praline allows the roots of a plant to be dipped in a praline mixture before planting.

[0036] According to another feature of the invention, the liquid biostimulant is used to impregnate a fertilizer. This fertilizer may, for example, be in the form of a granular fertilizer.

[0037] According to one feature of the invention, the liquid biostimulant is applied to soils by spreading.

[0038] Other features, details and advantages of the invention will become clearer upon reading the following description on the one hand, and the illustrative and non-limiting examples of embodiments given with reference to the accompanying schematic drawings on the other hand, in which:

[0039] [Fig. 1] schematically represents a general view of a plant operating symbioses with microorganisms present in the liquid biostimulant so as to promote photosynthetic activity and nutrient uptake;

[0040] [Fig.2] schematically represents the impact of using a biostimulant liquid according to the present invention on a potato culture compared to a control.

[0041] The features, variants, and different embodiments of the invention may be combined in various ways, provided they are not incompatible or mutually exclusive. In particular, variants of the invention may be considered that comprise only a selection of features, described hereafter in isolation from the other described features, if this selection of features is sufficient to confer a technical advantage or to differentiate the invention from the prior art.

[0042] It should be noted that the mass percentages which will be mentioned in the following description are to be considered in relation to the total mass of biostimulant considered.

[0043] The invention provides a biostimulant to ensure good crop quality and yields. The biostimulant according to the invention can be used in particular in forestry, horticulture, viticulture, and agriculture, and in all agricultural production systems.

[0044] According to one aspect of the invention, the biostimulant is a liquid composition intended to be diluted for application, for example by means of a sprayer, to the soil or to a growing medium. By way of illustrative and non-limiting examples of the invention, this growing medium may consist of compost, potting soil, peat, sand, or any other element that ensures optimal plant growth. It is understood from the foregoing that when using a growing medium, the liquid biostimulant is introduced into the growing medium, preferably by ensuring homogenization between the growing medium and the liquid biostimulant.

[0045] According to another aspect of the invention, the biostimulant is a liquid composition intended to be applied pure, i.e. at maximum concentration, on a solid fertilizer or amendment or mixed with a liquid fertilizer.

[0046] The fluidity of the biostimulant composition according to the invention is assessed according to the viscosity of the latter, which is between 0.02 and 0.25 Pascal-second.

[0047] In addition, to allow the spraying of the composition by conventional spraying systems, particularly those used in agriculture, the biostimulant comprises particles whose size is less than 250 µm, preferably less than 200 µm, more preferably less than 150 µm, even more preferably less than 100 µm.

[0048] The biostimulant according to the invention is a product miscible at least with water; preferably, the biostimulant according to the invention is miscible with any homogeneous aqueous solution. It is understood from the foregoing that mixing the biostimulant with water yields a homogeneous product. Thus, the biostimulant according to the invention can be sprayed onto crops using a sprayer; alternatively, the biostimulant can be used in the irrigation system of a fertigation installation; alternatively, the biostimulant can also be used in aeroponic production systems. In these production systems, the miscibility of the biostimulant allows its use without risk of clogging the various spray nozzles used. Furthermore, this miscibility of the biostimulant also allows its use in hydroponic systems, in which the biostimulant can be distributed homogeneously.

[0049] The biostimulant comprises vermicompost extract. Vermicompost is obtained by the decomposition of processed organic matter by earthworms. This vermicompost, also known as worm compost or worm humus, can be obtained from any of the earthworm species suitable for vermicompost formation. In particular, vermicompost can be obtained from any of the following earthworm species: Eisenia fetida, Eisenia andrei, Eisenia hortensis, Eudrilus eugeniae, and Lumbricus rubellus.

[0050] Vermicompost is an essential component of the biostimulant; this vermicompost exhibits numerous biostimulant effects. In particular, this vermicompost is characterized by a strong capacity to improve soil quality by increasing the C / N ratio and enhancing soil enzymatic activity, especially the activity of phosphatases, which make phosphates from the clay-humus complex available, and ureases, which mineralize urea nitrogen.

[0051] Vermicompost contains a high concentration of microorganisms capable of generating symbioses, particularly with plant root systems, thereby stimulating plant growth and improving nitrogen fixation. These microorganisms also exhibit enzymatic activity, enabling them to to solubilize phosphates present in the soil and to improve plant protection against soil-borne diseases.

[0052] Furthermore, the vermicompost used in the production of the biostimulant promotes the development in the soil of fungivorous, bacteriophagous, and nematophagous nematodes, as well as mycorrhizal fungi and PGPR bacteria (Plant Growth Promoting Rhizobacteria). These microorganisms, which develop following the application of the biostimulant to the soil, further enhance the biostimulant's action as a soil fertility enhancer, a reducer of sensitivity to abiotic and biotic stresses, and a growth stimulator.

[0053] The previously mentioned vermicompost goes through an extraction step to obtain vermicompost extract allowing all the previously mentioned characteristics of vermicompost to be put into solution.

[0054] According to the invention, the biostimulant comprises at least one strain of bacteria of the genus Bacillus, at least one strain of bacteria of the genus Azotobacter, and at least one strain of bacteria of the genus Rhizobium. These bacteria are used for their biostimulant roles in promoting plant development.

[0055] More specifically, the biostimulant may include a combination of bacteria according to the invention from among Azotobacter chroococcum, Azotobacter armeniacus, Azotobacter nigricans, Bacillus subtilis, Paenibacillus spp., Pseudomonas fluorescens, Pseudomonas sp., Brevibacterium, Mesorhizobium, Lysinibacillus, Bradyrhizobium, Az.ospirillum sp., Dietzia n. atronolimnaea, Flavobacterium sp., Brevundimonas sp., Rhizobium sp.

[0056] These bacteria are present in the biostimulant in a dormant state, which significantly limits microbial activity within the biostimulant once it has been packaged. To promote the dormancy of the microorganisms, the biostimulant includes preservatives such as cinnamaldehyde. Furthermore, the dormancy of the bacteria present in the liquid biostimulant is achieved, according to one embodiment of the invention, by maintaining the liquid biostimulant at an acidic pH. Also, according to this embodiment of the invention, the pH of the biostimulant is between 2 and 6, preferably between 3 and 5, preferably between 3.5 and 4.5, more preferably between 3.8 and 4.3, and even more preferably between 4.0 and 4.3.

[0057] A pH of the biostimulant within the ranges mentioned limits the degradation of compounds by microorganisms present in the biostimulant at a pH that is too acidic and limits microbial activity at a pH that is too neutral. More specifically, a pH of 4.0 limits the degradation of compounds and microorganisms present in the biostimulant better than a pH of 3.8 and better than a pH of 3.5. Furthermore, a pH of 4.3 limits microbial activity within the biostimulant better than a pH of 4.5 and better than a pH of 5. Therefore, it is clear that a compromise must be found to limit microbial activity in the biostimulant without degrading the compounds and microorganisms present within it. The inventors were thus able to determine that a pH between 3.5 and 4.5, and preferably between 3.8 and 4.3, provides an optimal compromise.

[0058] The pH of the biostimulant is maintained within the desired range by adding citric acid at a mass percentage of between 0.1% and 3%, preferably between 0.5% and 1.5%. It should be noted that the mass percentage of citric acid incorporated into the biostimulant is determined to obtain a pH of interest for the biostimulant in accordance with what has been previously stated. Furthermore, any other acidifying agent may be used at optimal mass percentages to obtain a pH in accordance with what has been previously stated.

[0059] The bacteria thus put into dormancy will be activated during the natural rise in pH occurring during the use of the biostimulant, for example during the dilution of the biostimulant in a volume of water at neutral pH before spraying on crops.

[0060] It should be noted, however, that in an alternative embodiment of the invention, the pH of the liquid biostimulant can be maintained at neutral pH, and more specifically between 6 and 8. In this embodiment of the invention, the presence of the aforementioned preservatives alone is sufficient to keep the microorganisms present in the liquid biostimulant dormant. Maintaining such a neutral pH between 6 and 8 thus preserves the buffering capacity of the liquid biostimulant and limits the degradation of microorganisms.

[0061] In another embodiment of the invention, the pH of the biostimulant is maintained between 8 and 12. In this embodiment of the invention, the presence of preservatives and an alkaline pH helps maintain the dormancy of microorganisms. Furthermore, a basic pH of the solution improves the solubilization of humic acids present in the liquid biostimulant. It should be noted that, for this embodiment of the invention, the liquid biostimulant comprises an alkaline agent such as ash, lime, or caustic soda.

[0062] In addition, the vermicompost extract includes many secondary metabolites such as phenolic compounds promoting the branching of the root system and ensuring protection against oxidative stress.

[0063] Furthermore, vermicompost contains numerous plant hormones that are also found in vermicompost extract. These plant hormones are synthesized by certain bacteria present in the earthworm microflora, including auxins, gibberellins, cytokinins, and brassinosteroids. The supply of phytohormones provided by the biostimulant effectively stimulates the plant growth, and in particular to promote seed germination and vegetative growth. Furthermore, the presence of phytohormones also significantly improves photosynthetic activity and fruit size. This plant stimulation thus improves the yields of crops biostimulated by the biostimulant according to the present invention.

[0064] Figure 1 illustrates the effects of vermicompost extract on a plant 2. Specifically, the introduction of a liquid biostimulant 1 according to the present invention at soil level provides the plant 2 with, on the one hand, a wealth of microorganisms 4 in close proximity to the plant 2, and more specifically to its root system 6, and on the other hand, humic substances 8 and an extract of at least one alga 10, as will be described in more detail in the following description. This deposition of microorganisms 4 in close proximity to the plant 2 promotes the formation of symbioses 12 between these microorganisms 4 and the root system 6 of the plant 2. Furthermore, these symbioses 12 promote nutrient uptake from the soil, thereby improving the foliage of the plant 2 and thus its photosynthetic activity.

[0065] Furthermore, the extract of at least one alga 10 is rich in high molecular weight alginates. Among the microorganisms 4 provided by the liquid biostimulant 1, microorganisms 4' enable the depolymerization of complex polysaccharides with a weak biostimulant effect, such as the alginates mentioned above, into smaller fractions of low molecular weight such as oligoalginates which have a much greater biostimulant effect.

[0066] According to one embodiment of the invention, the biostimulant comprises a mass percentage of vermicompost extract of between 10% and 80%, preferably between 30% and 80%, more preferably between 40% and 80%, more preferably between 40% and 70%, even more preferably between 50% and 70%.

[0067] The vermicompost extract is obtained by extracting the compounds and molecules of interest from the vermicompost resulting from the decomposition of organic matter by earthworms. This vermicompost is a solid material that is not compatible with application by spraying a liquid product. It is understood from the above that the extraction of vermicompost makes it possible to preserve the compounds and elements of interest in the vermicompost while allowing, for example, the spraying of this vermicompost extract.

[0068] More specifically, the vermicompost extract is obtained by extracting a mass percentage of vermicompost in solid state of between 2% and 40%, preferably between 10% and 40%, more preferably between 20% and 30% in a volume of water made up to 100%.

[0069] Within the mass percentage ranges of vermicompost used to obtain the vermicompost extract described above, the extraction of compounds of interest present in the raw material processed by the earthworms is optimal. Indeed, the higher the raw material content, the higher the content of compounds of interest or microorganisms in the vermicompost extract. However, the inventors have shown that beyond 40% vermicompost used to obtain the vermicompost extract, the extraction is not optimal and many compounds of interest are not extracted. Furthermore, at very low concentrations, specifically below 2%, the content of compounds of interest in the vermicompost extract is too low, thus limiting its effectiveness.

[0070] It is also understood that a compromise between the quality of the extraction carried out and the content of compounds of interest must be found. The inventors were able to determine that this optimal compromise is achieved in a mass percentage of vermicompost between 5% and 40%, and preferably between 10% and 30%.

[0071] Furthermore, vermicompost extract contains high levels of humic substances, particularly humic and fulvic acids. Humic substances, as documented in particular by Rose et al. 2014 “A Meta-Analysis and Review of Plant-Growth Response to Humic Substances” and Nardi et al. 2021 “Chemical Structure and Biological Activity of Humic Substances Define Their Role as Plant Growth Promoters,” significantly improve the bioavailability of macro- and micronutrients through their ability to chelate minerals. Moreover, their complex chemical forms offer a strong capacity to buffer soil pH and form aggregates that contribute to improving the physical and physicochemical structure of the soil. In addition to their action on the soil, which limits the occurrence of water and salt stress, humic substances activate antioxidant enzyme systems, thereby increasing plant resistance to these same stresses.

[0072] Furthermore, humic substances also have a hormonal-like action that stimulates growth, particularly root growth. This action was highlighted by Rose et al. (2014), especially with regard to humic substances derived from vermicompost. The origin of this action is generally attributed to their complex shapes, which allow them to enclose smaller molecules, such as phytohormones, within these larger structures (Canellas et al., 2002, 2015; Wong et al., 2020). Thus, humic substances from vermicompost are formed in the presence of phytohormones and manage to enclose them within their molecular structures. These humic substances therefore significantly improve the effectiveness of the biostimulant.

[0073] Also, according to the invention, the biostimulant comprises a mass percentage of humic substances of between 2% and 20%, preferably the biostimulant comprises a mass percentage of humic substances between 5% and 15%, more preferably the biostimulant comprises a mass percentage of humic substances between 7% and 12%. It should be noted that these mass percentages of humic substances are obtained in accordance with the analytical method RD 1110 / 1991 (BOE 170 17 / 07 / 1991 Met4).

[0074] The inventors were able to determine that an excessively high content of humic substances in the biostimulant increases the likelihood of particle precipitation within the biostimulant. Furthermore, an excessively high content of humic substances increases the C / N ratio of treated soils, which limits the availability and assimilation of nitrogen by plants.

[0075] In some embodiments, the mass percentage of humic acid is equal to the mass percentage of fulvic acid plus or minus 1%. In other embodiments, the mass percentage of fulvic acid is greater than the mass percentage of humic acid by at least 2%.

[0076] The results presented below in connection with Table 1 highlight the impact of the use of the liquid biostimulant, according to the present invention, on different crops compared to a control belonging to the same crop and on which no biostimulant was applied.

[0077] It is particularly noteworthy that the use of the liquid biostimulant at a dose of 5 liters per hectare (L / ha) on a wheat crop at the germination or seedling growth stage increases yields by 5.92 quintals per hectare (q / ha), representing a 6.8% increase in yields. It is also noteworthy that the use of the liquid biostimulant at a dose of 5 liters per hectare on a sugar beet crop at the germination stage increases yields by 108.9 quintals per hectare, representing a 13% increase in yields.

[0078] The use of the biostimulant according to the invention also improves straw yields. Furthermore, tests carried out on a flax crop have shown that the liquid biostimulant improves the assimilation of macro and micronutrients, particularly phosphorus, boron, and nitrogen.

[0079] This improved assimilation of said macro and micronutrients, applied at the germination stage of flax at a dose of 3 liters per hectare, results in a 4 cm increase in stem length compared to a control flax crop. More specifically, the application of the biostimulant increases flax stem length by 7%. This increase in stem length leads to a 0.26 tonne per hectare (t / ha) increase in straw yields, representing a 6.4% yield increase. [Tables 1] Crop Input Quantity (L / ha) Yield (q / ha) Straw Yield (t / ha) Change Biostimulant t / Control Wheat Organic iostimulant 5 92.48 - +6.8% Control 0 86.56 - Beet Organic iostimulant 5 976.1 - +13% Control 0 867.2 - Flax Organic iostimulant 3 -4.34 +6.4% Control 0 -4.08

[0080] Fig. 2 illustrates another trial carried out on a potato crop with a biostimulant input of 5 liters per hectare during planting compared to a control without biostimulant.

[0081] Thus, [Fig. 2] illustrates by means of histograms the number of tubers (14 per size) and by means of curves the harvested mass (16 kilograms per size). It should be noted that in [Fig. 2], the results obtained on potatoes to which the liquid biostimulant was applied are represented by the hatched histograms and the solid line curve, while the control results are represented by the histograms with a solid background and the dashed line curve.

[0082] Also, it is particularly noteworthy from this trial that the use of the biostimulant increases both the number and size of the tubers obtained. This increase translates into an increase in the harvested mass and therefore the associated financial gain.

[0083] According to one aspect of the invention, the biostimulant comprises a mass percentage of at least one algal extract of between 2% and 20%, preferably between 5% and 15%, and more preferably between 6% and 12%. The inventors have demonstrated that the presence of at least one algal extract in the biostimulant stimulates plant growth and also increases resistance to water, salt, and heat stress. Furthermore, the inventors have also demonstrated that the presence of algal extracts in the proportions defined above improves crop yields and quality.

[0084] The extract of at least one alga in the biostimulant is rich in complex polysaccharides with biostimulating properties. Thus, the extract of at least one alga comprises a combination of at least one polysaccharide among mannitol, fucoidans, carrageenans, laminarins, alginates.

[0085] Furthermore, the extract of at least one alga activates immune genes responsible for the synthesis of PR proteins and phenolic compounds. The extract of at least one alga also increases chlorophyll levels and photosynthetic activity in plants. In addition, a significant portion of the effects of the extract of at least one alga is attributed to the presence of phytohormones, particularly auxins, gibberellins, and cytokinins, which increase the phytohormone content of the biostimulant. The action of these phytohormones results, among other things, in greater aboveground biomass and increased root system development. This increase in root and aboveground systems maximizes water and nutrient uptake, thus promoting crop yields.

[0086] The inventors have particularly emphasized that the contribution of the extract of at least one alga is especially optimized in brown algae of the class Phaeophyceae. More specifically, according to one aspect of the invention, the extract of at least one alga is obtained from algae belonging to the family Laminariales. Alternatively or in combination, the extract of at least one alga can be obtained from algae belonging to the family Fucaceae. By way of example, the extract of at least one alga can be obtained from Ascophyllum nodosum.

[0087] In certain embodiments, the biostimulant comprises a high content of amino acids from plant sources, particularly vermicompost extract and extract of at least one algae. These amino acids, of exogenous origin to the plants, enable them to overcome stress situations, particularly those related to periods of drought and the application of herbicides. Indeed, their exogenous origin provides the plants with amino acids that are directly convertible into proteins without requiring their biosynthesis.

[0088] The biostimulant may thus comprise a combination of amino acids of at least one of the following amino acids: Alanine, Arginine, Asparagine, Aspartate, Cysteine, Glutamate, Glutamine, Glycine, Histidine, Isoleucine, Leucine, Lysine, Methionine, Phenylalanine, Proline, Pyrrolysine, Selenocysteine, Serine, Threonine, Tryptophan, Tyrosine, Valine.

[0089] Also, the biostimulant comprises in certain embodiments a mass percentage of amino acids of between 0.05% and 5%, preferably between 0.5% and 3%, more preferably between 1% and 2%.

[0090] The inventors have demonstrated that these amino acid levels stimulate nitrogen nutrition in the plant. Furthermore, at these levels, the amino acids promote the establishment of microorganisms, enabling them to better adapt to the plant's environment.

[0091] Indeed, amino acids are an important source of nutrients for soil microorganisms, thereby increasing soil microbial biomass and consequently their metabolic activities, i.e. the degradation and mineralization of organic matter, as well as their PGPR activities.

[0092] It should be noted that, like polysaccharides, amino acids are important sources of nutrients for soil microorganisms.

[0093] In some embodiments, the biostimulant comprises a mass percentage of potassium of between 0.1% and 5%, preferably between 0.5% and 2%, a mass percentage of nitrogen of between 0.05% and 5%, preferably between 0.1% and 2% and a mass percentage of phosphorus of between 0.01% and 0.5%, preferably between 0.05% and 0.2%.

[0094] In certain embodiments, the biostimulant comprises a mass percentage of molasses between 5% and 15%, preferably between 6% and 13%, and more preferably between 7% and 12%. This molasses can be obtained from sugar beets or sugar cane. The inventors have demonstrated that, in these proportions, the addition of molasses provides a high content of nutrients and phenolic compounds without affecting the solubility of the other compounds during the preparation of the biostimulant.

[0095] The addition of molasses to the biostimulant allows for the valorization of a byproduct of sugar production that is very rich in sugars, minerals, and phenolic compounds with antioxidant properties. The molasses in the biostimulant improves soil fertility, particularly when used in organic fertilization. Furthermore, the presence of molasses in the biostimulant enhances root and shoot growth in young seedlings, especially when associated with PGPR bacteria such as those found in vermicompost, to which molasses provides an important source of nutrients for their development.

[0096] Furthermore, the high sugar and nutrient content of molasses improves the substrate quality for the growth of microorganism populations. Thus, molasses contributes to the revitalization of stressed soils, for example following flooding or excessive mechanization during soil preparation, and promotes the multiplication of commensal and beneficial bacteria that limit the establishment of pathogens.

[0097] The biostimulant may thus comprise a mass percentage of sucrose of between 0.1% and 10%, preferably between 0.3% and 7%, preferably between 0.5% and 5%, more preferably between 1% and 4%.

[0098] In some embodiments, the biostimulant comprises a mass percentage of phenylpropanoids of between 0.05% and 0.5%, preferably between 0.1% and 0.3%.

[0099] In some embodiments, the biostimulant comprises a mass percentage of xanthan gum between 0.05% and 0.2%. Xanthan gum creates a network that retains particles in suspension, thus preventing sedimentation. The inventors have determined that, at these mass percentages, xanthan gum retains the particles present in the biostimulant in suspension while adjusting the viscosity to a satisfactory level between 0.02 Pa·s and 0.25 Pa·s. Furthermore, xanthan gum is a polysaccharide that promotes microbial growth in treated soils.

[0100] The present invention achieves its objective by proposing a liquid biostimulant that meets the requirements of agriculture, and in particular of so-called "organic" agriculture, making it possible to respond effectively to the various constraints that plants undergo during their growth.

[0101] The present invention is not limited to the embodiments described here and also extends to any equivalent means and configuration as well as to any technically operative combination of such means.

Claims

Demands

1. Liquid biostimulant comprising at least a mass percentage of humic substances of between 2% and 20%, a mass percentage of extract of at least one alga of between 2% and 20% and an extract of vermicompost comprising at least one strain of bacteria of the genus Bacillus, at least one strain of bacteria of the genus Azotobacter and at least one strain of bacteria of the genus Rhizobium.

2. Liquid biostimulant according to claim 1, comprising a mass percentage of vermicompost extract of between 10% and 80%.

3. Liquid biostimulant according to any one of claims 1 and 2, comprising a mass percentage of vermicompost extract of between 40% and 70%.

4. Liquid biostimulant according to any one of claims 1 to 3, wherein the mass percentage of humic substances is between 5% and 15%.

5. Liquid biostimulant according to any one of claims 1 to 4, wherein the mass percentage of the extract of at least one algae is between 5% and 15%.

6. Liquid biostimulant according to any one of claims 1 to 5, wherein the extract of at least one alga is obtained from algae from the class Phaeophyceae.

7. Liquid biostimulant according to claim 6, wherein the extract of at least one alga is obtained from algae from the Laminariales family.

8. Liquid biostimulant according to any one of claims 1 to 7, comprising a mass percentage of amino acids between 0.05% and 5%.

9. Liquid biostimulant according to claim 8, wherein the mass percentage of amino acids is between 0.5% and 3%.

10. Liquid biostimulant according to any one of claims 1 to 9, comprising a mass percentage of sucrose of between 0.1% and 10%.

11. Liquid biostimulant according to any one of claims 1 to 10, comprising a mass percentage of molasses between 5% and 15%.

12. Liquid biostimulant according to any one of claims 1 to 11, comprising a mass percentage of xanthan gum between 0.05% and 0.2%.

13. Liquid biostimulant according to any one of claims 1 to 12, comprising a mass percentage of solvent made up to 100%.

14. Liquid biostimulant according to any one of claims 1 to 13, comprising a pH between 2 and 12.

15. Use of a liquid biostimulant according to any one of the preceding claims for soil treatment

16. Use of a liquid biostimulant according to the preceding claim, wherein the liquid biostimulant is applied in a dosage of between 1 and 30 liters per hectare.

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