Cellulosic composition

Abstract

There is provided a method for producing a cellulosic composition for use as a soil supplement in agriculture, as a filter media or insulation comprising the steps: a) providing a cellulosic material with a dry content of ≥ 10 wt% by dry weight; b) adding a cationic polyelectrolyte in a content of 0.01-5 wt% by dry weight of cellulosic material to the cellulosic material having a dry content of ≥ 10 wt% by dry weight; and c) mixing the cellulosic material and the cationic polyelectrolyte.

Description

CELLULOSIC COMPOSITIONTECHNICAL FIELD

[0001] The present disclosure relates to the field of cellulosic compositions, and in particular to a cellulosic composition for use as a soil supplement in agriculture, as a filter media or insulation.BACKGROUND

[0002] By human activity with the use of fossil oil and gas as an energy source the CO2 emissions in the atmosphere increases rapidly with global warming. Residuals from crops and cereal production emits billion of tons of CO2 into the atmosphere when decomposing. Harvest residuals from food production of the big four (corn, wheat, soya bean, rice) emit more than 5 billion CO2 eq. Within a month and a year more than 40% and 80% respectively of the carbon in a wheat straw has been decomposed into CO2.

[0003] Agriculture is the practice of cultivating soil, growing crops, and raising animals for food, fiber, medicinal plants, and other products used to sustain and enhance human life. It is a critical component of human civilization, providing the primary source of food and raw materials.

[0004] Crop production includes growing a wide variety of plants such as grains, vegetables, fruits, and flowers. This involves irrigating and fertilizing for which there are problems to overcome including keeping the crops from drying out.

[0005] Filter media are materials used in filtration systems to remove particles, impurities, or contaminants from air, water, or other fluids.

[0006] Insulation refers to materials used to reduce the transfer of heat, sound, or electricity between environments.

[0007] There is an increased environmental concern, and products that traditionally have been based on synthetic materials are now desirable to replace with natural options. Filter medias and insulation are two areas where it would be desirable to use bio-based options instead. There are, however, problems to overcome to implement such transition.SUMMARY

[0008] One objective of the present disclosure is to provide a soil supplement which improves nutrient content, and overall health of crops, in particular by improving soil moisture retention and provision of nutrients. In addition, the soil supplement improves the humus level and thereby the yield of crops or plants, and carbon sequestration. Carbon sequestration reduces the amount of CO2 and methane in the air.

[0009] There is also an objective of the present disclosure to provide a bio-based filter media as well as a bio-based insulation material.

[0010] Accordingly, as a first aspect of the present disclosure there is provided a method for producing a cellulosic composition for use as a soil supplement, as a filter media or insulation comprising the steps: a) providing a cellulosic material with a dry content of > 10 wt% by dry weight; b) adding a cationic polyelectrolyte in a content of 0.01-5 wt% by dry weight of cellulosic material to the cellulosic material having a dry content of > 10 wt% by dry weight; and c) mixing the cellulosic material and the cationic polyelectrolyte.

[0011] As a second aspect of the present disclosure, there is provided a cellulosic composition with a dry content of > 10 wt% by dry weight for use as a soil supplement as a filter media or insulation comprising a cellulosic material and 0.01-5 wt% cationic polyelectrolyte by dry weight of the cellulosic material.

[0012] As a third aspect of the present disclosure, there is provided use of the composition according to the second aspect of the present disclosure as a soil supplement, as insulation, as filter media, as wipes or as absorbent mats.

[0013] As a fourth aspect of the present disclosure there is provided a mulch comprising the composition according to the second aspect of the present disclosure.

[0014] As a fifth aspect of the present disclosure there is provided a substrate for supporting growth of plants, wherein said substrate comprises a cellulosic material, said cellulosic material comprising cellulose fibers and a cationic polyelectrolyte adsorbed on said cellulose fibers.

[0015] As a sixth aspect of the present disclosure there is provided a method for producing a substrate for supporting growth of plants, wherein said method comprises the steps of: a) Selecting a cellulosic material comprising cellulose fibers; b) Mixing said selected cellulosic material with water thereby forming a stock; c) Adjusting a pH of said stock to be pH 7,0 or below; d) Adding a cationic polyelectrolyte to said stock; e) Allowing said cellulose fibers to adsorb the cationic polyelectrolyte; and f) Dewatering said stock thereby forming a dewatered acidic cellulosic material, said dewatered acidic cellulosic material forming said substrate.DETAILED DESCRIPTION

[0016] According to a first aspect of the present disclosure there is provided a method for producing a cellulosic composition for use as a soil supplement in agriculture, as a filter media or insulation comprising the steps: a) providing a cellulosic material with a dry content of > 10 wt% by dry weight; b) adding a cationic polyelectrolyte in a content of 0.01-5 wt% by dry weight of cellulosic material to the cellulosic material having a dry content of > 10 wt% by dry weight; and c) mixing the cellulosic material and the cationic polyelectrolyte.

[0017] Soil supplements are materials added to soil to improve for example its humus level, physical properties, nutrient content, and overall health. The soil is used in agriculture, horticulture and / or composts. Accordingly, the cellulosic composition can be added directly to soil in agriculture, the cellulosic composition can also be added directly to soil in horticulture, the cellulosic composition can also be added to a compost to improve composting. Soil produced in the compost can later be added to agriculture and / or horticulture. To be suitable for use as a soil supplement it is important that the cellulosic composition can be added to and distributed in the soil.

[0018] The inventors have realized that the cellulosic composition when put in soil contributes with water retention, which is beneficial by decreasing dehydration of soil, also known as soil desiccation. Without being bound to any theory it is believed that when the cationic polyelectrolyte is added to the cellulosic material, the cationicpolyelectrolyte binds to the cellulosic material providing a protection of the cellulosic material keeping the moisture from evaporating out into the atmosphere by for example wind and sunshine. Thereby, the cellulosic material can provide moisture to the soil and crops which increases the mulch content. In many parts of the world, in particular where there is a dry climate, e.g. in southern parts of Europe, India, California or parts of South America or Africa, there is a problem with that crops are not growing satisfactory due to too low mulch content. Therefore, the crops are not growing until needed to provide food. In addition, as yet another consequence the crops residues are incinerated. One traditional way of increasing mulch content is by addition of peat. However, when harvesting peat, high amounts of C02are released into the atmosphere, which is negative as it increases the greenhouse effect.

[0019] Moreover, the composition also provides nutrients, in particular in case the cationic polyelectrolyte is a nitrogen-containing polyelectrolyte. Further, the inventors have also realized that the cellulosic material in the composition does not degrade as fast and / or to the same extent as untreated cellulosic material and thereby sequester carbon. With reduced decomposition of cellulosic material, the nutrients in the soil can to a greater extent be for the plant and not for the microbes in the soil decomposing cellulosic material. Accordingly, the composition provides a combination of water retention, nutrient provision and carbon sequestration.

[0020] As is understood by the skilled person, the cellulosic material has a dry content > 10 wt% when adding the cationic polyelectrolyte. The inventors have realized that if the dry content is low, e.g. addition of the cationic polyelectrolyte to the cellulosic material in a suspension, the adsorption of the cationic polyelectrolyte is of significantly less quantity due to the dilution effect of the cellulosic material being provided with a higher water content. Thereby, even though if the same amount in dry weight of cationic polyelectrolyte would be added to the same amount in dry weight of cellulosic material the adsorbed cationic polyelectrolyte is significantly less since such suspension is typically dewatered and dried directly after addition not providing enough time for a high degree of adsorption. Advantageously, the cellulosic material provided in step a) has an even higher dry content of > 15 wt% by dry weight, such as > 20 wt% by dry weight. Moreover, with a much lower dry content, such as in case of a pulp suspension having a dry content of about 0.1 wt% by dry weight, there is also a need for excessive dewatering which is a disadvantage from acost and efficiency perspective. With a higher dry content it allows for impregnation and use of the cellulosic material without any active dewatering step between said impregnation and use.

[0021] Yet another advantage is reduced smell of the cellulosic material. In particular in the case of the cellulosic material being a material notorious for its unpleasant smell, such as manure, it is an advantage bad smell is reduced.

[0022] The cellulosic material is typically wood material, such as wood chips, wood shavings, sawdust, cutter chips and / or bark; plant fibers, such as straw, hemp, jute, flax, bagasse, elephant grass, bamboo and / or cotton; pulp fibers, such as wood pulp and / or regenerated cellulose fibers; fiber sludge, biosludge, peat, organic waste, green manure, composted organic material, farmyard manure, such as cattle manure and / or horse manure, agricultural residues, organic material from crop areas and gardens, harvest residuals such as from corn, cereals, rice, soya beans, rape or mixtures thereof. Typically, the cellulosic material is divided into pieces to facilitate mixing and spreading. The inventors have further realized that cellulosic material having a composition close to the composition of the corresponding raw material provides an improved effect in terms of carbon sequestration and resistance to degradation. Without being bound to any theory, it is believed that the less chemically refined the raw material is, the more efficient is the adsorption of cationic polyelectrolyte. Accordingly, mechanical pulp fibers are preferred over chemical pulp fibers as the mechanical pulp fibers have a chemical composition similar to that of native wood. Likewise, cellulosic material being only slightly processed, such as wood material, plant fibers, fiber sludge, biosludge, peat, organic waste, green manure, composted organic material, farmyard manure, agricultural residues, organic material from crop areas and gardens, harvest residuals such as from corn, cereals, rice, soya beans, rape or mixtures thereof are preferred over pulp fibers being less desirable to use as they have been previously treated in a pulping process. Moreover, it is more cost-efficient to use unprocessed cellulosic material as no pulping has been conducted and in case of pulp fibers provided in a suspension, the dry content is typically low, e.g. about 0.1 wt% by dry weight, and dewatering issues therefore also arises. Accordingly, the cellulosic material is preferably mechanical wood pulp, wood material, plant fibers, fiber sludge, biosludge, peat, organic waste, green manure, composted organic material, farmyard manure, agricultural residues, organicmaterial from crop areas and gardens, harvest residuals such as from corn, cereals, rice, soya beans, rape or mixtures thereof, even more preferably, wood material, plant fibers, fiber sludge, biosludge, peat, organic waste, green manure, composted organic material, farmyard manure, agricultural residues, organic material from crop areas and gardens, harvest residuals such as from corn, cereals, rice, soya beans, rape or mixtures thereof.

[0023] Chemical pulp fibers are made by breaking down the lignin in wood using chemicals, which helps in separating the fibers. Examples of chemical pulp fibers are kraft pulp, sulfite pulp, soda pulp and semi-chemical pulp. Mechanical pulps are produced by grinding or refining wood chips into fibers without significant chemical processing, retaining more lignin. Examples of mechanical pulp fibers are groundwood pulp, refiner mechanical pulp (RMP), thermomechanical pulp (TMP) and chemi-thermomechanical pulp (CTMP).

[0024] As understood by the skilled person, the term cellulosic material refers to a material comprising cellulose not to be confused with the term cellulose, which refers to only cellulose. A cellulosic material typically comprises further components, e.g. hemicellulose, lignin, inorganic compounds etc., and the whole material is still a cellulosic material.

[0025] In case the dry content of the cellulosic material is < 10 wt% by dry weight, the effect of combined water retention of plants, provision of nutrients and carbon sequestration is not obtained. Such case is for example if the polyelectrolyte is added to suspension of cellulosic material, e.g. a pulp suspension.

[0026] Preferably, the cellulosic material is non-delignified cellulosic material. Accordingly, the lignin content of the cellulosic material is typically at least 3% by dry weight, such as at least 5% by dry weight according to ASTM E1758-01. It has been realized that the combined effect of water retention, nutrient provision and carbon sequestration is improved if the cellulosic material is non-delignified.

[0027] Typically, the cationic polyelectrolyte in step b) is added with an aqueous solvent. Aqueous solvents are solvents in which water is the primary component. In such case, the concentration of the cationic polyelectrolyte in the aqueous solvent is typically 0.05-20 wt% by dry weight, such as 0.1-15 wt% by dry weight, such as 0.5-15 wt%. Typically, the cationic polyelectrolyte has an electrical conductivity in theaqueous solvent according to ISO 7888:1985 of at least 100 qS / cm, such as at least 300 qS / cm.

[0028] Typically, the cationic polyelectrolyte is a nitrogen-containing polyelectrolyte, preferably polyethylenimine (PEI), polyvinylamine (PVAm), cationic polyacrylamide (CPAM), cationic starch or mixtures thereof. A nitrogen-containing polyelectrolyte provides nutrition to crops growing in the soil. All crops require nitrogen for growth. However, the crops in the soil compete with microorganisms for nitrogen. Thereby, addition of a nitrogen-containing polyelectrolyte is beneficial for access to nitrogen of crops growing in the soil. In addition, the need for fertilizers is reduced.

[0029] A preferred way of adding the cationic polyelectrolyte is by spraying. Spraying is a method of applying liquids in the form of fine droplets. If the droplets are very small, such addition can also be referred to as misting. Within the present disclosure misting is a type of spraying. By spraying, potential dewatering problems are reduced or even omitted as the combination of the cellulosic material having a dry content of > 10 wt% by dry weight and spraying of the cationic polyelectrolyte, maintains the dry content at a high level, close to or even above 10 wt% by dry weight. A more efficient process is thereby provided. Moreover, spraying distributes the cationic polyelectrolyte in an efficient way in the cellulosic material.

[0030] Typically, the cationic polyelectrolyte is added to the cellulosic material in a content of 0.01-5 wt% by dry weight of cellulosic material, such as 0.05-5 wt% by dry weight of cellulosic material, such as 0.1-5 wt% by dry weight of cellulosic material.

[0031] In one embodiment the cellulosic material is agricultural residues. Agricultural residues are the by-products left over from the cultivation and processing of crops. These residues can be divided into two main categories: field residues and processing residues. Field residues are the parts of the crop that remain in the field after harvesting, for example stalks and stems being non-harvested portions of plants like corn stalks, wheat straw, and rice straw. Processing residues are by-products generated during the processing of agricultural products, for example husks and shells being outer coverings removed from grains, nuts, and seeds. In such embodiment, it is particularly preferred that agricultural residues are collected followed by addition of the polyelectrolyte, mixing and drying in the field where thecrops are being cultivated. For example, by using the same machinery to conduct all four steps. In such case, there is typically an intermediate step between mixing and drying which is distribution of the composition in soil. The drying can subsequently be conducted by drying in the sun. Such distribution can be conducted by e.g. ploughing back the composition into the soil or spreading it out on the soil. The agricultural residues maybe divided into smaller pieces. Typically, at least the field residues are divided into smaller pieces to allow for improved mixing with the cationic polyelectrolyte and distribution in soil. Moreover, harvest residuals from agriculture and food production are beneficial to use from a climate perspective, as it has been estimated that 10% reduction of CO 2 eq from decomposition of harvest residuals from the big four cereals will reduce the CO2 emission by 0.5 billion ton per year.

[0032] The method may further comprise an additional step: d) drying the mixed cellulosic material and the cationic polyelectrolyte.

[0033] The method is not limited to a certain type of drying. The drying can for example be conducted by drying at ambient temperature or drying at an elevated temperature. The drying is typically conducted by a non-contact method, e.g. by convection drying, IR-drying, air drying, vacuum drying, solar drying, microwave drying. A non-contact method is preferred over a contact method, e.g. press drying, as a contact-method is disadvantageous as it disrupts the structure of the cellulosic composition.

[0034] It may be advantageous to dry the mixed cellulosic material and the cationic polyelectrolyte. In particular when the cellulosic composition is for use a filter media or insulation a drying step is preferred. In case of the filter media, the drying facilitates transportation as less water is needed to be transported. Even though drying is advantageous from a perspective of transportation, it is not necessary to dry the mixed cellulosic material and the cationic polyelectrolyte for use as a filter media. The filter media can be used as is directly after mixing.

[0035] The inventors have realized that in particular when the cellulosic composition is for use as a soil supplement, the drying step is not necessary as the mixing of the cellulosic material and the cationic polyelectrolyte to provide thecellulosic composition suffices. The cellulosic composition can thereafter be directly used in the soil.

[0036] The dry content of the cellulosic composition after drying is typically > 10 wt% by dry weight. The dry content of the cellulosic composition may be even higher, such as > 20 wt% by dry weight, such as > 30 wt% by dry weight, such as > 40 wt% by dry weight, > 50 wt% by dry weight, such as > 60 wt% by dry weight, such as > 70 wt% by dry weight, such as > 80 wt% by dry weight.

[0037] For the avoidance of doubt, the method is preferably carried out in the order steps a)-c) followed by optional step d).

[0038] Typically, the composition comprises at least 95% cellulosic material by dry weight of the composition, such as at least 97% by dry weight of the composition.

[0039] Typically, the cellulosic composition and polyelectrolyte constitutes at least 95% by dry weight, such as at least 97% by dry weight, such as at least 98% by dry weight, such as least 99% by dry weight of the composition.

[0040] The cellulosic composition may further comprise clay. Preferably, said clay comprises plateau clay. Plateau clay has shown to have beneficial properties for holding water in the composition as well as to further improve the water uptake by the composition. In case the composition comprises clay, the composition typically comprises 5-20 wt% by dry weight of clay and 75-95 wt% by dry weight of cellulosic material.

[0041] As a second aspect of the present disclosure, there is provided a cellulosic composition with a dry content of > 10 wt% by dry weight for use as a soil supplement in agriculture as a filter media or insulation comprising a cellulosic material and 0.01-5 wt% cationic polyelectrolyte by dry weight of the cellulosic material.

[0042] Preferably, the cellulosic composition is provided divided into finely divided pieces, e.g. particles, or in bales. Bales are preferred in case production of the cellulosic composition is conducted at a first location and the usage is at a second location separate of the first location requiring transport of the cellulosic composition. A bale is a compressed bundle of loose material in contrast to webs, sheets or moulded three-dimensional structures that are either continuous or structured forms used differently in production or manufacturing. In case production and usage is at the same location, it is advantageous if the cellulosic composition isprovided into finely divided pieces, e.g. particles, as distribution of the cellulosic composition is facilitated.

[0043] Typically, the cellulosic composition has a density of < 600 kg / m3, such as < 550 kg / m3. If the cellulosic composition is provided in particle form, the density can for example be measured according to ASTM £873-82(2013). On the other hand, if the cellulosic composition is provided in bales the density can for example be measured according to ISO 8115-1:1986.

[0044] The examples and embodiments discussed above in connection to the first aspect apply to the second aspect mutatis mutandis.

[0045] As a third aspect of the present disclosure, there is provided use of the composition according to the second aspect of the present disclosure as a soil supplement, as insulation, as filter media, as wipes or as absorbent mats.

[0046] Filter media are materials used in filtration systems to remove particles, impurities, or contaminants from air, water, or other fluids. Just as filter media, wipes and absorbent mats are used to remove particles, impurities, or contaminants. Absorbent mats are not limited to mats of a certain size, but includes e.g. pads, towels, pillows, socks, sheets, booms, rugs and runners. Absorbent socks are long, flexible tubes designed to contain and absorb spills around machinery or in confined areas. Absorbent booms are larger, more robust tubes used for containing large spills, particularly on water bodies. Absorbent pillows are square or rectangular pillows that absorb large quantities of liquid in specific areas. Absorbent rolls are long sheets of absorbent material in roll form, allowing users to cut them to custom lengths as needed. Absorbent rugs and runners are designed for floor coverage, offering absorption over a large surface area while also functioning as a protective mat.

[0047] In a preferred embodiment of use of the composition as wipes or as absorbent mats, the cellulosic composition comprises a mixture of cellulosic fibers being pulp fibers and non-pulp fibers. In such case, it is preferred that the composition comprises at least 10% by dry weight of pulp fibers with respect to the fiber content.

[0048] Insulation refers to materials used to reduce the transfer of heat, sound, or electricity between environments.

[0049] The examples and embodiments discussed above in connection to the first and second aspects apply to the third aspect mutatis mutandis.

[0050] As a fourth aspect of the present disclosure there is provided a mulch comprising the composition according to the second aspect of the present disclosure.

[0051] A mulch is a layer of material applied to the surface of soil.

[0052] The examples and embodiments discussed above in connection to the first, second and third aspects apply to the fourth aspect mutatis mutandis.

[0053] The present disclosure also provides for the following itemized listing of embodiments:1. A substrate for supporting growth of plants, wherein said substrate comprises a cellulosic material, said cellulosic material comprising cellulose fibers and at least one of a cationic polyelectrolyte, a lignin and a terpene adsorbed on said cellulose fibers.2. The substrate according to item 1, wherein a concentration of said cationic polyelectrolyte adsorbed on said cellulose fibers is 0,001-30 wt-% of a dry weight of said cellulose fibers, preferably 0,005-20 wt-% and more preferred 0,01-10 wt-%.3. The substrate according to item 1 or 2, wherein a concentration of said lignin adsorbed on said cellulose fibers is 0,001-30 wt-% of a dry weight of said cellulose fibers, preferably 0,005-20 wt-% and more preferred 0,01-10 wt-%.4. The substrate according to anyone of item 1 to 3, wherein a concentration of said terpene adsorbed on said cellulose fibers is 0,001-30 wt-% of a dry weight of said cellulose fibers, preferably 0,005-20 wt-% and more preferred 0,01-10 wt-%.5. The substrate according to anyone of the preceding items, wherein said terpene is a triterpene; said triterpene preferably comprises betulin.6. The substrate according to anyone of the preceding items, wherein said cationic polyelectrolyte comprises at least one of a starch-based polyelectrolyte, polyethylenimine, polyacrylamide, chitosan, cationic gelatin, polydiallyldimethylammonium chloride (PDDA), poly(acrylamide-co- diallyldimethylammonium chloride) (Poly(AM-co-DADMAC), polyallylamine, , polyvinylamine, polyvinylphosphonic acid, and poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) or a mixture of two or more thereof.7. The substrate according to any one of the preceding items, wherein saidcellulosic material is selected from wood material comprising wood chips, wood shavings, sawdust, cutter chips and / or bark; wood pulp, regenerated cellulose fibers, organic waste, composted organic material, organic material from crop areas, residuals from biogas production and water treatment plats, recycled fibers, fiber sludge, bark sludge; non-wood pulp, plant fibers such as fibers from bamboo, bagasse, cotton, hemp, flax, and jute, or mixtures thereof.8. The substrate according to item 7, wherein said wood pulp is selected from softwood pulp, hardwood pulp, High Yield Pulp (HYP), dissolving pulp, chemical pulp such as kraft pulp, sulphate pulp or sulphite pulp, recycled paper and board, broke, cellulose nano pulp, dissolving pulp, deinked pulp (DIP), and said nonwood pulp is selected from straw pulps, hemp pulps, bagasse pulps, regenerated fibers; or a combination of one or more of these.9. The substrate according to item 8, wherein said High Yield Pulp (HYP) is selected from mechanical pulp, refiner mechanical pulp (RMP), thermomechanical pulp (TMP), chemi-thermomechanical pulp (CTMP), defibrated fiber-material, high temperature chemi-thermomechanical pulp (HTCTMP), chemi-mechanical pulp (CMP), stone groundwood pulp (SGW), pressure groundwood pulp (PGW), or a mixture thereof.10. The substrate according to anyone of the preceding items, wherein said substrate further comprises an amount of cellulose fibers not comprising said adsorbed cationic polyelectrolyte, lignin, or terpene and selected from any of the cellulosic materials as defined in items 7-9.11. The substrate according to any one of the preceding items, wherein said substrate further comprises macronutrient(s), micronutrient(s), chemical binder(s), natural gum(s), interlocking manmade fiber(s), soil, pumic stone, peat, and / or seed.12. The substrate according to any one of the preceding items, wherein said substrate comprises clay; preferably, said clay comprises plateau clay.13. The substrate according to item 12, wherein a content of said clay is within an interval of 1-30 vol-% as calculated on a total volume of the substrate, preferably 2- 15 vol-%, and more preferred 3-10 vol-%.14. The substrate according to any one of the preceding items, wherein said substrate has a pH lower than pH 7,0, preferably equal to pH 6,5 or lower, and more preferred equal to pH 6,0 or lower.15- The substrate according to any one of the preceding items, wherein said substrate has a pH equal to pH 3,5 or higher, and more preferred pH 4,0 or higher; preferably said substrate has a pH within an interval of pH 4,5-pH 6,0.16. The substrate according to any one of the preceding items, wherein a value of N-immobilisation is equal to or less than 30.17. A method for producing a substrate for supporting growth of plants, wherein said method comprises the steps of: a) Selecting a cellulosic material comprising cellulose fibers; b) Mixing said selected cellulosic material with water thereby forming a stock; c) Adjusting a pH of said stock to be pH 7,0 or below; d) Adding at least one of a cationic polyelectrolyte, a lignin and a terpene to said stock; e) Allowing said cellulose fibers to adsorb said at least one of the cationic polyelectrolyte, the lignin and the terpene; f) Dewatering said stock thereby forming a dewatered acidic cellulosic material, said dewatered acidic cellulosic material forming said substrate.Optionally adding a flocculant agent and / or a chelate agent after b).18. The method according to item 17, wherein adjusting the pH of step c) to be pH 7,0 or lower is performed prior to addition of said at least one of the cationic polyelectrolyte, the lignin and the terpene; and wherein said pH is adjusted simultaneously as mixing said cellulosic material with water or after mixing said water with said cellulosic material.19. The method according to item 17 or 18, wherein allowing said cellulose fibers to adsorb said at least one of the cationic polyelectrolyte, the lignin and the terpene for a residence time of at least 1 second, preferably at least 1 minute, and more preferred at least 10 minutes.20. The method according to any one of item 17-19, wherein said step f) further comprises:- at least one dewatering step fl) of said stock after the adsorption of said at least one of the cationic polyelectrolyte, the lignin and the terpene onto said cellulose fibers; and- at least one washing step f2) of adding water to said stock, and wherein said steps fi) and f2) are performed prior to adding said acid.21. The method according to item 20, wherein said dewatering in step fl) is performed until a concentration of said cellulosic material cellulosic fibers and said at least one of the cationic polyelectrolyte, the lignin and the terpene adsorbed on said cellulosic fibers is more than 30 wt-%, preferably more than 40 wt-%, and calculated as a dry weight.22. The method according to any one of items 17-21, wherein adjusting said pH in step c) to pH 7,0 or lower, preferably to pH 6,0 or lower,23. The method according to any one of items 17-22, wherein said method further comprises at least one step of stirring of said stock, wherein said stirring is performed within a time interval of 0,5-60 minutes.24. The method according to any one of items 17-23, wherein a dry weight of the cellulose fibers in step b) is 0,1-30 wt-% of the total weight of the stock, preferably 0,5- 10 wt-%, and more preferred 1-5 wt-%.25. The method according to any one of items 17-24, wherein said dewatering step g) comprises at least one of pressing, filtering and centrifuging said substrate to a dryness of 40 wt-% or more, preferably 50 wt-% or more.26. The method according to any one of items 17-25, wherein said method further comprises a drying step after said dewatering step g); and wherein said drying is performed until a dryness of 70-90 wt-% of a dry weight of said substrate has been reached, preferably 75-85 wt-%.27. The method according to any one of items 17-26, wherein adjusting pH in said step c) to be equal to pH 7,0 or lower, preferably equal to pH 6,5 or lower and more preferred equal to pH 6,0 or lower.28. The method according to any one of items 17-27, wherein said adjustment of pH in step c) is performed by addition of a weak acid and / or an acid salt.29. The method according to any one of items 17-28, wherein said method further comprises a step of adding clay to said substrate, preferably said clay comprises plateau clay.30. The method according to item 29, wherein a content of said clay is within an interval of 1-30 vol-% as calculated on a total volume of said substrate, preferably 2-15 vol-%, and more preferred 3-10 vol-%.31. The method according to any one of items 17-30, wherein said method further comprises a step of heating at least one of said cellulosic material, said stock, said cationic polyelectrolyte, said lignin and said terpene.32. The method according to any of the items 17-31, wherein said step of heating comprises heating said cellulosic material to a temperature of 50 °C or more, preferably to a temperature of 70 °C, and more preferred to a temperature of 80 °C or more; preferably said heating is performed by at least one of addition of steam, electrical heating, gas heating or hot water.33. The method according to any one of items 17-32, wherein said cationic polyelectrolyte comprising at least one of a starch-based polyelectrolyte, polyacrylamide, chitosan, cationic gelatin, polydiallyldimethylammonium chloride (PDDA), poly(acrylamide-co-diallyldimethylammonium chloride) (Poly(AM-co- DADMAC), polyallylamine, polyethylenimine, polyvinylamine, polyvinylphosphonic acid, and poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA), or a mixture of two or more thereof.34. The method according to any one of items 17-33, wherein a concentration of said cationic polyelectrolyte in the stock maybe within an interval of 0,001-30 wt- % of a total weight of said stock, preferably 0,005-20 wt-%, and more preferred 0,01-10 wt-% of said total weight of said stock.35. The method according to any one of items 17-34, wherein a concentration of said lignin in the stock is within an interval of 0,001-30 wt-% of a total weight of said stock, preferably 0,005-20 wt-%, and more preferred 0,01-10 wt-% of said total weight of said stock.36. The method according to any one of items 17-35, wherein a concentration of said terpene in the stock is within an interval of 0,001-30 wt-% of a total weight of said stock, preferably 0,005-20 wt-%, and more preferred 0,01-10 wt-% of said total weight of said stock, preferably said terpene is a triterpene and wherein said triterpene preferably is betulin.37. The method according to any one of items 17-36, wherein said cellulosic material is selected from wood material comprising wood chips, wood shavings, sawdust, cutter chips and / or bark; wood pulp, organic waste, composted organic material, residuals from biogas production, regenerated cellulose fibres, recycled fibers, fiber sludge, bark sludge, non-wood pulp, plant fibres such as fibres from bamboo, bagasse, cotton, hemp, flax, and jute, or mixtures thereof.38. The method according to item 37, wherein said wood pulp is selected from softwood pulp, hardwood pulp, High Yield Pulp (HYP), dissolving pulp, chemical pulp such as kraft pulp, sulphate pulp or sulphite pulp, recycled paper and board,broke, cellulose nano pulp, dissolving pulp, deinked pulp (DIP), regenerated fibers, and said non-wood pulp is selected from straw pulps, hemp pulps, bagasse pulps, or a combination of one or more of these.39. The method according to item 38, wherein said High Yield Pulp (HYP) is selected from mechanical pulp, refiner mechanical pulp (RMP), thermomechanical pulp (TMP), chemi-thermomechanical pulp (CTMP), defibrated fiber-material, high temperature chemi-thermomechanical pulp (HTCTMP), chemi-mechanical pulp (CMP), stone groundwood pulp (SGW), pressure groundwood pulp (PGW), or a combination of one or more of these.40. The method according to any one of items 17-39, wherein said substrate further comprises an amount of cellulose fibers not comprising said cationic polyelectrolyte or lignin or terpene, and selected from the cellulosic materials as defined in items 38-39, and added to said initial step of preparing said stock, to said stock and / or after dewatering said stock.41. The method according to any one of items 17-40, wherein said method further comprises addition of at least one of macronutrient(s), micronutrient(s), chemical binder(s), natural gum(s), interlocking manmade fiber(s), soil, pumice stone, and peat to said substrate.42. The method according to any one of items 17-41, wherein said method comprises a step of grinding said cellulose fibers to a fiber average length within an interval of 1-30 mm, preferably said grinding step is performed prior to said mixing in step b) and / or after said dewatering and / or said drying.

[0054] The substrate in the itemized listing is used interchangeably with the composition referred to in the first, second, third and fourth aspects of the present disclosure.

[0055] In a fifth aspect of the present disclosure, there is provided a substrate for supporting growth of plants, wherein said substrate comprises a cellulosic material, said cellulosic material comprising cellulose fibers a cationic polyelectrolyte adsorbed on said cellulose fibers.

[0056] The examples and embodiments discussed above in connection to the first, second, third and fourth aspects apply to the fifth aspect mutatis mutandis.

[0057] In a sixth aspect of the present disclosure, there is provided a method for producing a substrate for supporting growth of plants, wherein said method comprises the steps of: a) Selecting a cellulosic material comprising cellulose fibers; b) Mixing said selected cellulosic material with water thereby forming a stock; c) Adjusting a pH of said stock to be pH 7,0 or below; d) Adding at least one of a cationic polyelectrolyte to said stock; e) Allowing said cellulose fibers to adsorb the cationic polyelectrolyte; and f) Dewatering said stock thereby forming a dewatered acidic cellulosic material, said dewatered acidic cellulosic material forming said substrate.

[0058] A step of lowering said pH to 7.0 or below, i.e. to an acidic pH, of the substrate creates a good environment for growth of plants and good adsorption of the cationic polyelectrolyte onto said cellulose fibers. One advantage is that the lowering of pH is performed by addition of a weak acid and / or an acid salt that is non-toxic to human beings. The plants growing in the substrate will not adsorb toxic chemicals.

[0059] “Biobased” as used herein means products derived from raw, natural materials biological products, forestry materials, or renewable domestic agricultural materials, including plant, animal, or marine materials. Typically, these products, which are composed in whole or in significant part of the raw natural materials, provide a renewable alternative to conventional petroleum derived products.“Organic waste” as used herein means biodegradable, compostable waste from homes, businesses, institutions, and industrial sources. Examples include food scraps, yard and garden trimmings, food-soiled paper products and biosolids.

[0060] “Mild acid” or “weak acid” is an acid that partially dissociates into its ions in an aqueous solution or water. In contrast, a strong acid fully dissociates into its ions in water. The conjugate base of a weak acid is a weak base, while the conjugate acid of a weak base is a weak acid.

[0061] “Macronutrients” as used herein are nutrients needed in large amounts, examples of macronutrients are nitrogen (N), phosphorus (P), potassium (K), sulphur (S), calcium (Ca), silica (Si), and magnesium (Mg). For example, P is needed for early root formation and growth. For the growth phase, as a rule, a nutrient mixture with a higher N value is used because plants need extra nitrogen for vegetative growth. Forthe flowering phase, an NPK content with a higher P and K value is used to increase fruit and flower production.

[0062] “Micronutrients” as used herein are nutrients needed in small amounts. Examples are boron (B), chloride (Cl), copper (Cu), iron (Fe), manganese (Mn), molybdenum (Mo), nickel (Ni), sodium (Na), cobalt (Co), and zinc (Zn).Micronutrients are important for plant growth, as plants require a proper balance of all the essential nutrients for normal growth and optimum yield.

[0063] “Germination” as used herein is the growth of a plant contained within a seed; it results in the formation of the seedling. It is also the process of reactivation of metabolic machinery of the seed resulting in the emergence of radicle. Seed germination depends on both internal and external conditions. The most important external factors include right temperature, water, oxygen or air and sometimes light or darkness.

[0064] “Germination rate” as used herein describes how many seeds of a particular plant species, variety or seedlot are likely to germinate over a given period. It is a measure of germination time course and is usually expressed as a percentage, e.g., an 85% germination rate indicates that about 85 out of 100 seeds will probably germinate under proper conditions over the germination period given.

[0065] “Horticulture clay” or plateau clay for horticulture as used herein is a type of fine- grained natural soil material containing clay minerals.

[0066] “Water uptake” as used herein denotes the process by which water (and dissolved nutrients) in soil is drawn into the plants. Examples of water uptake may e.g. be by diffusion or osmosis.

[0067] “Nitrogen immobilisation” or “N immobilisation” as used herein refers to the process in which nitrate and ammonium are taken up by soil organisms and therefore become unavailable to crops. A low N immobilisation means that more nitrogen is available to the crops.

[0068] “Bonding” as used herein shall be widely interpreted and include, but are not limited to, ionic bonding, covalent bonding, inter-molecular forces and hydrogen bonding.

[0069] “Lignin” is a natural, amorphous polymer, consisting of carbon, hydrogen and oxygen and can be found in all trees and plants. About 30 % of all things thatgrow contain lignin. It is the second most abundant biomass in the world after cellulose. Lignin can be extracted as a residue in a paper pulp mill, from the ’’black liquor” - so-called ’’Kraft lignin”. Lignin is also an abundant residue from agricultural activities, such as sugar and lignocellulosic ethanol production.

[0070] “Terpene” is a class of natural products consisting of compounds with the formula (C5H8)n for n > 2.

[0071] An interval of said dry weight of the cellulose fibers comprised in the stock is 0.1-30 wt-% of the total weight of the stock, preferably 0.5-10 wt-%, and more preferred 1-5 wt-%.

[0072] In some embodiments, said step of mixing may comprise a washing step bi) wherein said cellulosic material is mixed with water, possibly under stirring, and then dewatering the mixture. Said washing step bi) maybe performed one or several times. The washing step is followed by mixing said cellulosic material with water now forming the stock that is to be pH-adjusted in step c). Said washing step bi) maybe advantageous to reduce electrical charges and, if the cellulosic material comprises too high levels of compounds such as e.g. sodium, chloride, sulphate, sulphur and / or heavy metals, to lower the levels of said compounds.

[0073] Said method further comprises step c), adjusting a pH of said stock to be on or below pH 7,0, i.e. to be acidic. Adjusting pH may in some embodiments not be necessary. Accordingly, within the present disclosure the wording adjusting the pH refers to setting the pH. For example, a fiber sludge may already be acidic when mixing it with water in step b) for forming said stock. This means that if a pH of said stock comprising said fiber sludge already is low enough, said step c) - adjusting the pH to be acidic - may not be needed. Hence, step c) reads setting a pH of said stock to be pH 7.0 or below.

[0074] Said pH of the stock is adjusted to pH 7,0 or lower-Preferably, said pH is adjusted to pH 6,0 or lower. Said adjustment / lowering of pH is performed by addition of a weak acid and / or an acid salt.

[0075] Said weak acid is typically selected from dihydrogen carbonate, formic acid, acetic acid, benzoic acid, carbonic acid, citric acid, tartaric acid, lactic acid, hydrofluoric acid, phosphoric acid, sulphurous acid, and nitrous acid, or combinations thereof.

[0076] In some embodiments, hydrochloric acid (HC1) may be used as acidifier. Said acid salt is typically selected from sodium hydrogen sulphate and ammonium chloride, or a mixture thereof. A step of stirring of the basic stock may be performed for 1-60 minutes. Said mixing of the cellulosic material with water and said pH adjustment, and possibly also said stirring, may be performed simultaneously.

[0077] Said method further comprises step d), adding the cationic polyelectrolyte to said basic stock.

[0078] A concentration of the cationic polyelectrolyte in the stock is preferably equal to or greater than 0,001 wt-% of a dry weight of cellulose fibers in the stock, more preferred equal to or greater than 0,005 wt-%, and most preferred equal to or greater than 0,01 wt-%. In order not to overdose the cationic polyelectrolyte but rather to optimize the dose, an upper limit of the cationic polyelectrolyte in the stock is equal to or lower than 30 wt-% of a dry weight of cellulose fibers in the stock, preferably equal to or lower than 20 wt-%, and more preferred equal to or lower than 10 wt-%. A concentration interval of the cationic polyelectrolyte in the stock maybe within the interval of 0,001-30 wt-% cationic polyelectrolyte of a total weight of said stock, preferably 0,005-20 wt-%, and more preferred 0,01-10 wt-%.

[0079] Said method further comprises step e), allowing said cellulose fibers to adsorb the cationic polyelectrolyte. With the word “allowing” is meant that said cellulose fibers are exposed to the cationic polyelectrolyte so that said fibers can adsorb said cationic polyelectrolyte.

[0080] Said cellulose fibers may be allowed to adsorb said cationic polyelectrolyte for a residence time of at least 1 second, preferably at least 1 minute, and more preferred at least 10 minutes, and preferably not more than 24 hours. Said residence time starts when adding said polyelectrolyte to said stock meaning that step d) - adding said polyelectrolyte - and step d) - allowing the fibers to adsorb said polyelectrolyte - may be seen as one and the same step, or at least integrated with each other. In preferred embodiments said residence time for the adsorption of the cationic polyelectrolyte onto said cellulose fibers is 0,5- 240 minutes, preferably 5-60 minutes, and more preferred 10-30 minutes. Step e) may further comprise a step of stirring of the stock may be performed for 1-60 minutes. In some embodiments it may be preferred to adjust pH and add the cationic polyelectrolyte simultaneously, while in other embodiments said pH is adjusted after the addition of the cationicpolyelectrolyte. Embodiments are conceivable where step c) - step e) are performed simultaneously. Different plants to be grown in the inventive substrate require different pH, and the desired pH value of the substrate therefore varies.

[0081] Said method further comprises step f), dewatering said stock thereby forming a dewatered acidic cellulosic material and wherein said dewatered acidic cellulosic material forms said substrate.

[0082] It is to be understood that said dewatering step may comprise one or more sub steps of dewatering. Each sub step may be one of a pressing step, a filtering step and a centrifugation step and said substrate is preferably dewatered to a dryness of 40 wt-% or more, preferably 50 wt-% or more.

[0083] Said method may further comprise a drying step, step g), after said dewatering step f). Said drying maybe performed until a dryness of 70-90 wt-% of a dry weight of said substrate has been reached, and preferably to a dryness of 75-85 wt-%. In some embodiments, said method may further comprise at least one step of dewatering, step fl), of said stock after the adsorption of said cationic polyelectrolyte onto said cellulose fibers. Said dewatering may preferably be followed by at least one step of addition of water, step f2). Said dewatering in step fl) maybe performed until a concentration of said cellulosic material comprising said cellulosic fibers and the cationic polyelectrolyte adsorbed on said cellulosic fibers is more than 30 wt-%, preferably more than 40 wt-%, and calculated as a dry weight.

[0084] Said addition of water is performed such that a dry weight of the cellulose fibers in step f2) is 0,1-30 wt-% of the total weight of the stock, preferably 0,5-10 wt- %, and more preferred 1-5 wt-%. It is further to be understood that said dewatering step f) may comprise a washing step fl). After a first dewatering of the acidic cellulosic material, washing fluid, e.g. water, may be added to the dewatered cellulosic material, possibly during stirring and for a residence time of at least 30 seconds, followed by a second dewatering. This washing step may be repeated one or several times. A reason for washing the dewatered cellulosic material may e.g. be to wash away any remaining acid from acidifying step c). For example, chloride ions maybe present if hydrochloric acid was used as acidifier. The method may further comprise at least one additional step of stirring of said stock, wherein said stirring is performed within a time interval of 0,5-60 minutes.

[0085] The method may further comprise at least one step of temperature adjustment of said water and / or said stock and / or said washing fluid, at least one additional step of pH adjustment, or any combination thereof.

[0086] The method may further comprise a step of heating said cellulosic material. Said heating of said cellulosic material may be performed prior to mixing said selected cellulosic material with water thereby forming a stock in step b). In some embodiments said stock comprising said cellulosic material is heated. Said step of heating comprises heating said cellulosic material to a temperature of 50 °C or more, preferably to a temperature of 67 °C, and more preferred to a temperature of 7O°C or more; preferably said heating is performed by at least one of addition of steam, electrical heating, gas heating or hot water. One reason to perform said heating maybe to reduce the electrical charges. Another reason maybe to kill any spores, seeds, bacteria and microorganisms etc. that may be present in the cellulosic material. Said spores, seeds, bacteria and microorganisms may be unwanted in said substrate for supporting growth of plants.

[0087] Said method may further comprise addition of a chelating agent, e.g. EDTA, for capturing any heavy metals and / or a flocculant for capturing any charged particles if present in the cellulosic material selected. Said chelating agent and flocculant may be added e.g. in step b).

[0088] Said method may further comprise addition of a wetting agent, mainly sulfosuccinates or polyacrylates, for increased water uptake or a sixing agent, mainly starch-based derivatives, for reduced water uptake for fine tuning of the substrate. Said method may further comprise addition of an amount of cellulose fibers not comprising said adsorbed cationic polyelectrolyte. Said cellulose fibers may be selected at step a) and added e.g. in step b). Said cellulose fibers not comprising said adsorbed cationic polyelectrolyte maybe present in an amount within an interval of 1- 50 wt-%, preferably, 2-30 wt-% and more preferred 5-15 wt-%. Depending on which plants are to be grown in the substrate, different additives can be mixed into the substrate. Different plants have different needs for nutrients, water, water retention etc. The additives maybe either during production of the substrate or afterwards, to the finished substrate.

[0089] Clay is an example of an additive that may be added to the substrate. Preferably, said clay comprises plateau clay. Clay contributes to a water holdingcapacity of the substrate and possibly also creates water ways within the substrate. In some embodiments, said addition of clay is performed after said dewatering and / or after said drying of the substrate. A content of said clay is preferably within an interval of 1-30 vol-% as calculated on a total volume of the substrate, more preferred 2-15 vol-%, and most preferred 3-10 vol-%.

[0090] In some embodiments, peat may be added to the substrate such that a concentration of peat is equal to or lower than 80 wt-%, preferably equal to or lower than 70 wt-%, and more preferred equal to or lower than 50 wt-%.

[0091] Other additives that said substrate may further comprise are macronutrient(s), micronutrient(s), chemical binder(s), natural gum(s), interlocking manmade fiber(s), soil, pumic stone, peat, and / or seed.

[0092] A step of grinding the selected cellulosic material in step a) may be performed prior to performing step b) and / or after said dewatering and / or said drying. Said cellulose fibers may be grinded to a fiber average length within an interval of 1 mm - 30 mm.

[0093] For the avoidance of doubt, the cellulosic material is preferably the same as in the first aspect of the present disclosure. And also for avoidance of doubt, selecting a cellulosic material is the same as providing a cellulosic material.

[0094] Fiber sludges have shown to sometimes comprise too high concentrations of salts comprising sodium, chloride and sulphate. A washing step bi) as disclosed above may be advantageous for washing out or to at least lower the concentrations of said sodium, chloride and / or sulphate before forming the stock in step b). A preferred concentration of sodium in the stock maybe below 3 wt-%, preferably below 2 wt-%, and more preferred below 1 wt-%. The same figures apply for preferred concentrations of chloride.

[0095] In embodiments, a dry cellulosic material is mixed with lignin, wherein said lignin maybe a powder or a liquid. Preferably, said lignin is added such that the lignin content is within an interval of 0,5-30 wt -% of the dry weight of said cellulose fibers. Thereafter the mixture is heated to 5O°C or more, preferably 70-150 degrees for at least 30 seconds, preferably, 1-10 minutes. By heating the mixture, the lignin softens and adsorption to the cellulose fibers is thereby improved.

[0096] The examples and embodiments discussed above in connection to the first, second, third, fourth and fifth aspects apply to the sixth aspect mutatis mutandis.EXAMPLESEvaluation of water uptake

[0097] Water uptake is an indirect measurement on how much of the polyelectrolyte added to respective mixture that is absorbed by the cellulosic material. In case a low amount of polyelectrolyte is adsorbed, the water uptake is higher and in case a higher amount of the added polyelectrolyte is adsorbed, the water uptake is lower. Without being bound to any theory it is believed that the cationic polyelectrolyte adsorbs to the anionic charges of the cellulosic material, whereby the anionic charges are neutralized making the cellulosic material less polar leading to a lower absorption of water.Preparation of test specimens

[0098] Cellulosic raw materials being fiber sludge form a sulphate mill having a lignin content of about 25%, peat having a lignin content of about 15%, agricultural residues having a lignin content of about 10%, and pulp fibers having a lignin content of about 25% were tested.

[0099] The fiber sludge had a dry content of about 30-40 % by dry weight. Fiber sludge was sprayed with an aqueous solution of cationic polyelectrolyte (Xelorex, Solenis) with a concentration of 10% to provide an addition of 1.2% by dry weight of cationic polyelectrolyte with respect to the dry weight of the raw material followed by mixing and drying.

[0100] Moreover, the agricultural residues as well as peat having a dry content of above 90% by dry weight were separately sprayed with an aqueous solution of polyvinylamine (Xelorex, Solenis) with a concentration of 10% to provide an addition of 1.2% by dry weight of polyvinylamine with respect to dry weight if cellulosic material followed by mixing and drying.

[0101] Separately, pulp fibers were provided in an aqueous suspension at a concentration of about 1 % by dry weight and the aqueous solution of polyvinylamine (Xelorex, Solenis) having a concentration of 10% was sprayed into the suspension toprovide an addition of 1.2% by dry weight. The suspension was thereafter mixed, dewatered and dried.Evaluation of water uptake

[0102] Water uptake was quantified by measuring the weight of the fiber sludge after 20, 60 and 120 minutes. The results are presented in Table 1 below.Table 1. Water uptake.

[0103] As seen in Table 1 is there a significant difference in the water uptake of the unmodified fiber sludge compared with the fiber sludge that had polyelectrolyte added.

[0104] Likewise, both the peat and the agricultural residues displayed a significantly decreased water uptake in a similar test.

[0105] The pulp fibers impregnated with polyelectrolyte while the pulp fibers were in suspension, on the other hand, displayed a similar water uptake to unmodified pulp fibers.Evaluation of degradation by massPreparation of test specimens

[0106] Cellulosic raw materials being softwood Chemi Thermo Mechanical Pulp (CTMP) having a lignin content of about 25%, pine sapwood chips having a lignin content of about 25%, and birch sapwood chips having a lignin content of about 20%, were tested.

[0107] The CTMP had a dry content of about 25-40% and was sprayed with an aqueous solution of cationic polyelectrolyte (Xelorex, Solenis) with a concentration of 10% to provide an addition of 1.2% by dry weight of cationic polyelectrolyte with respect to the dry weight of the raw material followed by mixing and drying.[ooio8] The wood chips were left untreated as control samples. All samples were conditioned at 20 °C, 85 % RH and then planted in the soil to a depth of approximately 10 cm. Testing was conducted according to the European testing standard SS-ENV 807:2009 and evaluated after 32 weeks of degradation. The results are presented in Table 2 below.Table 2. Degradation test.

[0109] The impregnated CTMP fibers outperformed the pine as well as birch control samples.Evaluation of nitrogen-immobilizationPreparation of test specimens

[0110] Nitrogen-immobilization (N-immobilization) refers to the process of converting inorganic nitrogen (such as ammonium or nitrate) into organic forms, which are then incorporated into microbial biomass or organic matter. This process reduces the availability of inorganic nitrogen in the soil or aquatic environments, thus "immobilizing" it and preventing it from being readily accessible to plants or other organisms.

[0111] N-immobilization typically occurs when there is an abundance of carbon- rich organic material in the environment. Microorganisms use this carbon source for growth, and in doing so, they take up inorganic nitrogen from the surroundings to balance their nutrient needs, converting it into organic nitrogen in their biomass.

[0112] A nitrogen immobilization test was conducted on hydrangea soil evaluating the extent to which nitrogen is absorbed or retained by soil microorganisms, making it temporarily unavailable for plant uptake. In this test the cellulosic material is added to the soil and then left to incubate allowingmicroorganisms to act on nitrogen. After incubation, the remaining nitrogen levels in the soil are measured. This shows how much nitrogen has been immobilized (taken up by microbes) versus how much remains available for plant use. The difference between the initial nitrogen amount and the remaining nitrogen indicates the level of immobilization, which informs how effectively the hydrangea can access nitrogen from the soil.

[0113] Thereby, an N-immobilization test reflects how much extra nitrogen that would be needed to be added to the hydrangeas during growth. A lower number is therefore advantageous as less extra nitrogen is needed.Preparation of test specimens

[0114] Cellulosic raw materials being fiber sludge form a sulphate mill having a lignin content of about 25% and CTMP fibers having a lignin content of about 25% were tested.

[0115] The fiber sludge had a dry content of about 30-40 % by dry weight and the CTMP had a dry content of about 25-40% by dry weight. The fiber sludge and the CTMP were sprayed separately with an aqueous solution of cationic polyelectrolyte (Xelorex, Solenis) with a concentration of 10% to provide an addition of 1.6% by dry weight of cationic polyelectrolyte with respect to the dry weight of the raw material followed by mixing and drying. CTMP without any cationic polyelectrolyte was used as a reference. The fiber sludge was after drying pressed at 250-300 °C into pellets. All cellulosic materials were separately immobilized in the hydrangea soil.

[0116] The results of the N-immobilization is presented in Table 3 below.Table 3. Evaluation of N-immobilization.

[0117] The equipment can measure up to 30 mmol N per liter soil, at a higher level it is not possible to differentiate the results. Already after 1 week, the unmodified CTMP gave such result. It is preferred that the mmol of N per liter soil measured is about 20 or lower.Evaluation of water-holding capacity

[0118] Water-holding capacity reflects how well the internal water of the cellulosic material is kept within the cellulosic material so that it can continue to provide water to the soil as it has not been dried out.Preparation of test specimens

[0119] Saw dust from fir denoted “mulcher pale” having a lignin content of about 25% and a dry content of 92% by dry weight, two types of fiber rejects denoted “mulcher grey” and “mulcher brown” with a dry content of 92% by dry weight were sprayed with an aqueous solution of cationic polyelectrolyte (Xelorex, Solenis) with a concentration of 10% to provide an addition of 1.2% by dry weight of cationic polyelectrolyte with respect to the saw dust, and the two types of fiber rejects.

[0120] In addition, bark, polystyrene beads and vermiculite granules were used for comparison being commercially available mulcher products.

[0121] After addition of the cationic polyelectrolyte the materials were dried.Test set-up

[0122] Pots were filled with 65% water and 35% soil at a weight of about 33 g. Per rack there was in total 6 pots and each rack contained 200 g water and soil. To each pot, 7.5 ml of dry test specimen was added. As a control, to one pot no test specimen was added.

[0123] A fan was arranged 50 cm away from the racks and with constant air flow directing air onto the pots in the rack. Every 12thhour the pots were weighed to calculate the ability of holding water. The ability of holding water was evaluated asmass loss, the lower the mass loss, the better water-holding capacity. The results are presented in Table 4 below.Table 4. Evaluation of water-holding capacity.

[0124] The reference being void of the cationic polyelectrolyte displayed a higher water loss, i.e. a lower capacity of binding water. In particular during the first 48 hours there is a significantly reduced water loss of the treated samples compared with the reference and commercial mulchers (bark, polystyrene and vermiculite). This improvement is visualized in Table 2 above by the inserted row describing the water holding capacity compared with the reference after 24, 48, 72 and 96 h. All inventive examples displayed a significant improvement compared with the reference, also over time. Mulcher pale, being based on saw dust, an un -refined, i.e. not pulped, source of cellulosic material, displayed particularly good results.

[0125] Notably, the biobased mulchers have at least a comparable water-holding capacity compared with conventionally used polystyrene, bark and vermiculite, even for longer times, up to 96b.Evaluation Anaerobic degradationPreparation of test specimens

[0126] Two test specimens were used: wood fibers and wheat straw. The wood sample was wood fibers from wood residues - a mix of chips, bark and shavings from fir and pine having a lignin content of about 20-30% and the wheat straw had a lignin content of about 15%. The wood fibers and wheat straws were individually sprayed with an aqueous solution of cationic polyelectrolyte (Xelorex Solenis) with a concentration of 10% to provide an addition of 1.2% by dry weight of cationic polyelectrolyte with respect to the dry weight of the raw material followed by mixing and drying. As reference, wood fibers and wheat straw without any cationic polyelectrolyte addition was used. All fiber samples were sterilized in 120 °C for 60 minutes. In case of the inventive examples, the sterilization was conducted prior to addition of the polyelectrolyte.Anaerobic degradation

[0127] The degradation of the samples was conducted in batch digestion. The batchwise degradation was carried out in triplicate in 0.5 L bottles containing inoculum, sample, and water. The test bottles were placed on shaking tables in a constant temperature room at 37°C. The gas pressure and methane content were measured regiooularly. Gas pressure was used to measure gas production (normal gas volume, 1 atmiog and o°C). Gas samples were taken, and methane content was analyzed by gas chromii6atography (FID detector). The experiment included 15 samplings over an incubai2Otion period of approximately 45 days.

[0128] One reference stage with only the inoculum, to eliminate its contribution to gas formation, and a positive control to evaluate the activity of the inoculum, was included.

[0129] In the following Tables 5-6, the results from the anaerobic degradation tests are presented. In each table there is a column where the improvement is presented in percentage. This improvement represents how much less of each of the compounds CO2, and biogas was produced of the modified (inventive) examples. It is beneficial to release less carbon in terms of carbon sequestration. The average C as mg biogas and CO2 was measured per g of VS sample, where g VS refers to the amount of volatile solids in grams. Volatile solids are the portion of the sample thatcan be vaporized or burned off when heated to high temperatures, used to represent organic material.

[0130] In Table 5 below is the amount of carbon produced in the form of biogas being carbon dioxide as well as methane gas, during the anaerobic decomposition of straw presented.Table 5. Evaluation of anerobic decomposition of straw.

[0131] In Table 6 below is the amount of carbon produced in the form of biogas being carbon dioxide as well as methane gas, during the anaerobic decomposition of wood fibers presented.Table 6. Evaluation of anerobic decomposition of wood fibers.

[0132] For both the wood fibers and the straw there was a significant improvement in anaerobic conditions in terms of reduced degradation.Evaluation Aerobic degradationPreparation of test specimens

[0133] Four test specimens were used: wood fibers, corn residuals, cattle manure and horse manure. The wood sample was wood fibers from wood residues - a mix of chips, bark and shavings from fir and pine having a lignin content of about 20-30%. The wood fibers corn residuals, cattle manure and horse manure were individually sprayed with an aqueous solution of cationic polyelectrolyte (Xelorex Solenis) with a concentration of 10% to provide an addition of either 3.0% by dry weight (wood fibers, corn residues and cattle manure) or 5.0 wt% (horse manure) of cationic polyelectrolyte with respect to the dry weight of the raw material followed by mixing and drying (wood fibers and corn residues) or not drying (cattle manure and horse manure). As reference, wood fibers, corn residuals, cattle manure and horse manure without any cationic polyelectrolyte addition was used.Aerobic degradation

[0134] When microorganisms break down organic compounds in the compost, carbon dioxide is released into the air as a residual product. By measuring the amount of carbon dioxide produced from a given amount of material, the microbial activity can be analyzed.

[0135] The test specimens were individually mixed with compost and water according to Table 7 below. TS refers to total solids. In case of horse manure, nocompost was added. The content was mixed in a small bottle and put into a container together with a CO2 meter. The lid was closed. CO2 level was measure on a regular basis. When CO2 level increased to or above 5000 pm the lid was opened for 2 minutes. A duplicate of each sample was tested.Table 7. Amounts used in aerobic decomposition tests.

[0136] The following fractions were analyzed: a) Control with compost only (dry weight 40%), b) Unmodified test specimen with compost, and c) Modified test specimen with compost, or without compost in case of the horse manure.

[0137] The CO2 level from a) compost was deducted from b) and c) to provide the results. The results are presented in Tables 8-11 below.

[0138] In Table 8 below is the amount of oxygen gas produced during the aerobic decomposition of wood fibers presented. The improvement reflects how much lower the amount of CO2 produced was of the modified specimen compared with the unmodified specimen.Table 8. Evaluation of aerobic decomposition of wood fibers.

[0139] In Table 9 below is the amount of oxygen gas produced during the aerobic decomposition of corn residuals presented. The improvement reflects how much lower the amount of CO2 produced was of the modified specimen compared with the unmodified specimen.Table 9. Evaluation of aerobic decomposition of corn residuals.

[0140] In Table 10 below is the amount of oxygen gas produced during the aerobic decomposition of cattle manure presented. The improvement reflects how much lower the amount of CO2 produced was of the modified specimen compared with the unmodified specimen.Table 10. Evaluation of aerobic decomposition of cattle manure.

[0141] In Table 11 below is the amount of oxygen gas produced during the aerobic decomposition of horse manure presented. The improvement reflects how much lower the amount of CO2 produced was of the modified specimen compared with the unmodified specimen.Table 11. Evaluation of aerobic decomposition of horse manure.

[0142] For all test specimens there was a significant improvement in aerobic conditions in terms of reduced degradation.Evaluation of CO2 production from wood fibers and CTMP pulp fibersPreparation of test specimens

[0143] The wood fibers were wood residues - a mix of chips, bark and shavings from fir and pine having a lignin content of about 20-30%. The wood fibers were refined to < 4 mm granula and sterilized at 120 °C for 60 minutes. The CTMP pulp fibers had a lignin content of about 25%. The refined wood fibers having a dry content of 40% were impregnated by spraying with an aqueous solution of cationic polyelectrolyte (Xelorex 1300, Solenis) with a concentration of 10% to provide an addition of 1.6% by dry weight of cationic polyelectrolyte with respect to the dry weight of the raw material followed by mixing and drying. The same procedure was used for the addition of 1.6 wt% cationic polyelectrolyte to the CTMP pulp fibers. As reference, wood fibers as well as CTMP pulp fibers without any cationic polyelectrolyte addition was used.Evaluation of CO2 production using 1 g of test specimen

[0144] 1 gram of test specimen was mixed with 0.5 g compost and 2.5 g water. The content was mixed in a small bottle and put into a container together with a CO2 meter. The lid was closed. CO2 level was measure on a regular basis. When CO2 levelincreased to or above 5000 pm the lid was opened for 2 minutes. A duplicate of each sample was tested.

[0145] The following fractions were analyzed: d) Control with compost only (dry weight 40%), e) Unmodified wood fibers with compost, and f) Modified wood fibers with compost.

[0146] The CO2 level from a) compost was deducted from b) and c) to provide the results.

[0147] The carbon dioxide production during aerobic degradation was measured during an incubation time of in total 21 days. The amount of carbon dioxide produced from the impregnated, inventive, fibers is significantly lower than for the reference fibers. Accordingly, the carbon sequestration of the impregnated fibers is significantly higher than for the reference fibers. The results are presented in detail in Table 12 below.Table 12. Evaluation of CO2 production from wood fibers.Evaluation of CO2 production using 2 g of test specimen

[0148] 2 gram of test specimen was mixed with 1.0 g compost and 5.0 g water. The content was mixed in a small bottle and put into a container together with a CO 2 meter. The lid was closed. CO2 level was measure on a regular basis. When CO2 level increased to or above 5000 pm the lid was opened for 2 minutes. A duplicate of each sample was tested.

[0149] The following fractions were analyzed: a) Control with compost only (dry weight 40%), b) Unmodified wood fibers or CTMP pulp fibers with compost, and c) Modified wood fibers or CTMP pulp fibers with compost.

[0150] The CO2 level from a) compost was deducted from b) and c) to provide the results.

[0151] The carbon dioxide production during aerobic degradation was measured during an incubation time of in total 14 days. The amount of carbon dioxide produced from the impregnated, inventive, fibers is significantly lower than for the reference fibers. Accordingly, the carbon sequestration of the impregnated fibers is significantly higher than for the reference fibers. The results are presented in detail in Table 13 below.Table 13. Evaluation of CO2 production from wood fibers.

[0152] After 14 days of testing, the CTMP fibers impregnated with polyelectrolyte achieved a 23% improvement. For the wood material, on the other hand, a 43% improvement is achieved with the impregnation, i.e. in principle twice as much improvement as for CTMP. The inventors have thus realized that the impregnation as such is beneficial in both cases and particularly advantageous for a cellulosic material that has not been refined by a pulping process.Evaluation of different substrate mixtures for cultivationPreparation of test specimens

[0153] Cellulosic material being fiber sludge was sprayed with an aqueous solution of cationic polyelectrolyte (Xelorex, Solenis) with a concentration of 10% to provide an addition of 1.6% by dry weight of cationic polyelectrolyte with respect to the dry weight of the raw material followed by mixing and drying. Fiber sludge without any cationic polyelectrolyte was used as a reference.

[0154] The polyelectrolyte-containing fiber sludge was mixed with fiber sludge and / or clay and / or peat. The peat used in the substrate mixtures was Hasselfors natural peat without nutrients from Hasselfors Garden AB, Sweden. The clay used in the substrate mixtures was Bara Clay granulate 0-1 from Bara Mineraler AB, Sweden. Peat soil pellet was included in the test as a control substrate in the form of 100% peat soil pellets. Said peat soil pellets were provided by Nelson Garden AB, Sweden. The compositions of the different mixtures are presented below in Table 14.Table 14. Compositions prepared.Products and equipment used in cultivation test

[0155] Seed: Tomato Moneymaker, Solanum lycopersicum, Weibulls.

[0156] Nutrients: Botana Pot Plant Nutrition from Grona vaxter, Sweden. Formula of nutrition: 5 ml nutrients to 1 000 ml of water.

[0157] Perlite: Nelson Garden, Sweden.

[0158] Mini greenhouse: Nelson Garden Large 8 plantation trays, each with 6 pots, each pot 10 cl in volume.

[0159] Greenhouse lamp: 14 W, timer with 16 hours light per day.Preparation of cultivation

[0160] Each of the eight substrate mixtures was moistened with 20% of volume of water. 60 cl of each substrate mixture was moistened with 15 cl of tap water. The moistened substrate mixtures were placed in plantation trays, 10 cl of substrate mixture in each pot, six pots per plantation tray; i.e. one plantation tray comprising six pots per substrate mixture and in total eight plantation trays.

[0161] A cavity, 5 mm deep and 5 mm in diameter, was made in a surface of the substrate mixture in each pot. One seed was placed / planted in each cavity.

[0162] A perlite granule was placed to cover the seed in each cavity. Perlite, produced from a volcanic mineral substance, provides better structure through increased air volume and improved drainage.

[0163] 30 ml of water was added to each pot. The eight plantation trays were placed in the greenhouse, each with a cover covering the upper portion of the plantation tray. A temperature inside the greenhouse was kept at 20 °C.

[0164] A cultivation scheme for a cultivation period covering 21 days from day 1 to day 21 was strictly followed. Said cultivation scheme is presented in Table 15 below.Table 15. Cultivation scheme.

[0165] Two milliliters of water were added to each pot on the first two days of the cultivation period.

[0166] From day 3 to day 21 the greenhouse was arranged under a greenhouse lamp and was exposed toi6 hours of light per day.

[0167] On the third day perlite was removed from the surface of each substrate mixture.

[0168] On each of days 3-4, 6-9, 11-14 and 16-21, 2 ml of water was added to each pot.

[0169] On day 5, 10 ml of nutrition was added, and on day 10, 5 ml of nutrition was added to each pot.

[0170] The following parameters were measured during the cultivation period and at the end, day 21, of said period:- Average time to germination. Days after planting of seed.- Average time to root protrusion through substrate mixture.- First leaf, average days after planting.- Average Leaf Counts, 20 and 30 days after planting.- Average stem length and diameter after 21 days.Results of the cultivation

[0171] Each plantation tray contained six pots, all six pots of the same tray comprising one of the eight substrate mixtures. The average values presented in some of the tables below are calculated per plantation tray. A mean germination rate of the eight substrate mixtures was 100% for each substrate mixture meaning that all seeds germanized.

[0172] Average time to germination was measured and values are presented in Table 16. The average time to germination for seeds planted in the substrate mixtures “1”, “2”, “6” and “7”, was 2.5 days after planting. Of the eight substrate mixtures, these four substrate mixtures had the fastest average time to germination.

[0173] For substrate mixture “8”, the average time to germination was 2.7 days, while for “5” said time was 2-4 days, and in average it took 2.8 days to germinate.Table 16. Average time to germination, days after planting (measured % of total).

[0174] Seeds planted in all substrate mixtures comprising “1” started to germinate two days after planting.

[0175] Average time to root protrusion was measured for the eight substrates, and as can be seen in Table 17 below, seeds planted in “5”, containing no modified fiber sludge, had the longest average time, 5.7 days. The substrate mixtures in which the seeds had the shortest average time to root protrusion were “1”, “3”, and “7”. The average time to root protrusion for these three substrate mixtures was four days after planting.Table 17. Average time to root protrusion.

[0176] Number of days for a first leave to protrude was measured. Results are presented in Table 18 below.

[0177] The seeds planted in the substrate mixture “5” had the longest time for the first leaf to protrude, an average of 8.7 days, while the seeds planted in the substrate mixtures “1”, “2” and “3” had the shortest time for the first leaf to protrude, an average of 5.3 days.Table 18. Average time for a first leaf to protrude.

[0178] An average leaf count as well as stem length on day 20 and 30 after planting was performed for substrate mixtures no. “1”, “2” and “8” and results are presented in Table 19 below.Table 19. Average leaf count and stem length.

[0179] As can be seen in Table 19 the substrate mixture “2” had the highest average number of leaves 20 days after planting. Counting again after 30 days from planting showed that the seeds planted in the substrate mixtures “1” and “2” had the highest average number of leaves. All three mixtures had comparable stem length after 30 days.Electrical conductivity

[0180] Electrical conductivity, EC, (measured as milliSiemens per meter, mS / m) was measured.

[0181] A total of seven samples were prepared and consisted of untreated CTMP, untreated fiber sludge and CTMP and fiber sludge treated with PrimeBond, PVAm or lignin.

[0182] The following steps were performed for each sample:- Step 1 - washing step: 20 grams of dry fiber was mixed with 10L of tapwater (EC 0,17) and was left to stand for 4 hours.- Step 2- drying of the washed fibers at ioo°C for 4 hours.- Step 3 - measurement of EC: 10 grams of dry fiber was mixed with 100 ml deionised water. Measurement (relative) of EC of the mixture was performed after 6 hours. All samples had pH 7.

[0183] The results presented in Table 20 show that fibers having PVAm adsorbed on them had the lowest relative EC-values. The electrical charges of fibers comprising adsorbed PrimeBond were lower as compared to untreated fibers. The electrical charges of fibers comprising adsorbed PVAm were even lower.Table 20. Electrical conductivity.Filter media evaluationTest set-up

[0184] Cellulosic raw material being fiber sludge or saw dust were individually sprayed with an aqueous solution of cationic polyelectrolyte (Xelorex Solenis) with a concentration of 10% to provide an addition of 3.0% by dry weight of cationic polyelectrolyte with respect to the dry weight of the raw material followed by mixing and drying. The fiber sludge and saw dust were thereafter mixed with activated carbon and an ion exchanger to prepare a filter medium.

[0185] Contaminated water containing heavy metals, hydrocarbon contaminants or PFAS was thereafter passed through the filter medium. The results are presented in Tables 21-23 below.Table 21. Results from filtration of heavy metals.Table 22. Results from filtration of hydrocarbon contaminants.Table 23. Results from filtration of PFAS.Evaluation of smell from chicken manurePreparation of test specimens

[0186] Chicken manure (100 g dry weight) was mixed with water (400 g) to a total dry weight of 20 wt%. Polyvinyl amine was either added in a content of 3 wt% by dry weight (inventive example) or not added (comparative example). The mixtures were mixed for 5 minutes.Evaluation of smell

[0187] 6 people were asked to smell the two different mixtures and rate the intensity of the smell according to a scale from 1 to 3 where 1 was “no / little smell”, 2 was “medium smell” and 3 was “strong smell”.Results

[0188] For the inventive example, all 6 people rated the smell being “1” whereas for the comparative example 5 out 6 people rated the smell being “3” and 1 out 6 rated the smell being “2”.

[0189] Thereby, in addition to the advantages described throughout the present disclosure, a reduced smell is yet another advantage.

Claims

CLAIMS1. Method for producing a cellulosic composition for use as a soil supplement, as a filter media or insulation comprising the steps: a) providing a cellulosic material with a dry content of > 10 wt% by dry weight; b) adding a cationic polyelectrolyte in a content of 0.01-5 wt% by dry weight of cellulosic material to the cellulosic material having a dry content of > 10 wt% by dry weight; and c) mixing the cellulosic material and the cationic polyelectrolyte.

2. The method of claim 1, wherein the cationic polyelectrolyte in step b) is added with an aqueous solvent.

3. The method of claim 2, wherein the concentration of the cationic polyelectrolyte in the aqueous solvent is 0.05-20 wt% by dry weight, such as 0.1-15 wt% by dry weight, such as 0.5-15 wt%.

4. The method of claim 2 or 3, wherein the cationic polyelectrolyte has an electrical conductivity in the aqueous solvent according to ISO 7888:1985 of at least 100 pS / cm, such as at least 300 pS / cm.

5. The method of any one of the preceding claims, wherein the cationic polyelectrolyte is added by spraying.

6. The method of any one of the preceding claims, wherein the cationic polyelectrolyte is added to the cellulosic material in a content of 0.01-3 wt% by dry weight of cellulosic material, such as 0.05-3 wt% by dry weight of cellulosic material, such as 0.1-3 wt% by dry weight of cellulosic material.

7. The method of any one of the preceding claims, wherein the cellulosic material is wood material, such as wood and / or leaf brushwood, wood chips, wood shavings, sawdust, cutter chips and / or bark; plant fibers, such as straw, hemp, jute, flax, bagasse, elephant grass, bamboo and / or cotton; pulp fibers, such as wood pulp and / or regenerated cellulose fibers; fiber sludge, biosludge, peat, organic waste, green manure, composted organic material, farmyard manure, agricultural residues, organic material from crop areas and gardens, harvest residuals such as from corn, cereals, rice, soya beans, rape or mixtures thereof, preferably mechanical wood pulp,wood material, plant fibers, fiber sludge, biosludge, peat, organic waste, green manure, composted organic material, farmyard manure, agricultural residues, organic material from crop areas and gardens, harvest residuals such as from corn, cereals, rice, soya beans, rape or mixtures thereof, even more preferably, wood material, plant fibers, fiber sludge, biosludge, peat, organic waste, green manure, composted organic material, farmyard manure, agricultural residues, organic material from crop areas and gardens, harvest residuals such as from corn, cereals, rice, soya beans, rape or mixtures thereof.

8. The method of any one of the preceding claims, wherein the cationic polyelectrolyte is a nitrogen-containing polyelectrolyte, preferably polyethylenimine (PEI), polyvinylamine (PVAm), cationic polyacrylamide (CPAM), cationic starch or mixtures thereof.

9. The method of any one of the preceding claims, wherein the composition comprises at least 95% cellulosic material by dry weight of the composition, such as at least 97% by dry weight of the composition.

10. The method of any one of the preceding claims, wherein the lignin content of the cellulosic material is at least 3% by dry weight, such as at least 5% by dry weight according to ASTM E1758-01.

11. The method of any one of the preceding claims, wherein the cellulosic material provided in step a) has a dry content of > I5wt% by dry weight, such as > 20 wt% by dry weight.

12. The method of any one of the preceding claims, wherein the method further comprises the step of: d) drying the mixed cellulosic material and the cationic polyelectrolyte.

13. A cellulosic composition with a dry content of > 10 wt% by dry weight for use as a soil supplement in agriculture as a filter media or insulation comprising a cellulosic material and 0.01-5 wt% cationic polyelectrolyte by dry weight of the cellulosic material.

14. The composition of claim 13, wherein the cellulosic composition has a density of < 600 kg / m3, such as < 550 kg / m3.15- Use of the composition according to any one of the claims 13-14 as a soil supplement, as insulation, as filter media, as wipes or as absorbent mats.

16. A mulch comprising the composition according to any one of the claims 13-14.

17. A method for producing a substrate for supporting growth of plants, wherein said method comprises the steps of: a) Selecting a cellulosic material comprising cellulose fibers; b) Mixing said selected cellulosic material with water thereby forming a stock; c) Adjusting a pH of said stock to be pH 7,0 or below; d) Adding a cationic polyelectrolyte to said stock; e) Allowing said cellulose fibers to adsorb the cationic polyelectrolyte; and f) Dewatering said stock thereby forming a dewatered acidic cellulosic material, said dewatered acidic cellulosic material forming said substrate.

18. The method of claim 17, wherein the method further comprises a step of adding a flocculant agent and / or a chelate agent after step b).

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