WO2025007201A1

WO2025007201A1 - Wood fertilizer

Info

Publication number: WO2025007201A1
Application number: PCT/BR2024/050284
Authority: WO
Inventors: Jose Ribeiro DOS SANTOS JUNIOR; Jarbas MESQUITA JUNIOR
Original assignee: Individual
Current assignee: Individual
Priority date: 2023-07-04
Filing date: 2024-07-02
Publication date: 2025-01-09
Anticipated expiration: 2026-01-04

Abstract

The present invention relates to a production process and a product to be used as nitrogen fertilizer in agricultural plantations. The process involves: wood treatment steps (trees and/or shrubs and/or grasses) followed by two other steps, the preparation of the nitrogenous substance (melamine, methylol - melamine and all melamine derivatives) that will bind to wood (cellulose and/or hemicellulose) and the reaction of fixing the compound in the wood. The Product (nitrogenated wood (cellulose/hemicellulose) composite) was applied in agricultural experiments: in washed sand to test nitrogen release and in soil to monitor plant growth

Description

Title: Wood fertilizer

Background

Fertilization of soil for enhancing plant growth is an important aspect of providing sufficient food for the world population. Nitrogenous fertilizers provide nitrogen to the soil, which is an important element to sustain plant growth. By enhancing nitrogen presence in a soil, plant growth can be stimulated.

Existing nitrogen fertilizers (urea, ammonium nitrate, ammonium sulphate, and the like] have the drawback of a high solubility. Although high solubility facilitates distribution of the fertilizer through soil, and also facilitates uptake of (nitrogenous substances derived from] the fertilizer by the plant, it also results in leakage: nitrogenous substances may wash out of the soil by unavoidable processes such as watering (by hand or by rain], or by diffusion. This results in nitrogen loss, which hampers efficiency of use. Also, nitrogen leakage may be detrimental to the environment, for example in cases where agriculture is practiced in areas close to natural areas which naturally thrive in low nitrogen conditions. In such cases, the natural area may become enriched in nitrogen (nitrification], altering the natural state of the area.

Various techniques to avoid nitrogen leakage have been proposed. Various composites and resins are known, which slowly degrade to release nitrogen. However, such systems are generally laborious to prepare, requiring high energy. This diminishes the societal efficiency of use of nitrogen fertilization. In addition, such techniques may not be perceived as "natural”, which is a drawback in times where consumers more and more demand "natural” growth conditions in among others agriculture.

The present invention provides a fertilizer which overcomes the above drawbacks.

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SUBSTITUTE SHEET (RULE 26) Figures

Figure 1: Scanning electron microscopy (SEM) picture of the wood used in example 1 for preparing the fertilizer (A), and of the fertilizer of the invention (B).

Figure 2: The fertilizer of the invention after preparation and drying to equilibrium moisture content

Figure 3: (A): corn seeds seeded in pots containing washed sand enriched with the fertilizer of the invention in different proportions. (B) the same pots having germinated seeds after 7 days.

Figure 4: Leaf development of an exemplary corn plant grown in a soil mixture comprising washed sand and the fertilizer of the invention.

Figure 5: Corn plants grown in a soil mixture comprising washed sand and the fertilizer of the invention after 28 days.

Figure 6: schematic procedure for preparing the fertilizer of the invention by reacting a material comprising fibers from cellulose and/or hemicellulose with an aqueous hydroxide base to provide a material comprising activated cellulose and/or activated hemicellulose, and separately reacting a primary or secondary amine with a carbonyl compound to provide a reactive intermediate, and subsequently combining the material comprising activated cellulose and/or activated hemicellulose with the reactive intermediate to provide the fertilizer, which is thereafter isolated by filtration, dried and ground.

Detailed description

The invention provides a fertilizer comprising fibers from cellulose and/or hemicellulose, wherein said fibers comprise covalently bonded nitrogen-containing side groups.

The present fertilizer can be used for (nitrogen] fertilization for most common plants. It is an advantage of the present invention that the fertilizer provides high efficiency of nitrogen fertilization, essentially without leakage to the environment. The present fertilizer provides for increased duration of nitrogen presence in the soil where it was admixed to,

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SUBSTITUTE SHEET (RULE 26) without increasing nitrogen levels to the environment. There is no need for multiple rounds of application in most types of agricultural practice, and due to the prolonged presence, there is a decreased need for transportation.

In addition, the fertilizer can be made using readily accessible materials, in an easy to use process. The present fertilizer is essentially a natural fertilizer, capable of providing sustained nitrogen presence for prolonged periods of time. In addition, the present fertilizer may be used to enhance water retention, and/or to enhance soil aeration, and the character anionic of the material, what easy the permutation of cations.

A plant, as herein defined, can be any plant, such as a wild plant (defined as a plant which grows naturally in its location], an ornamental plant, an agricultural plant, or a horticultural plant. Plants suitable for use in food are preferred, such as human food or animal feed. Further preferred are plants which require high quantities of nitrogen for optimal growth. The skilled person knows which plants require high quantities of nitrogen, in order to achieve optimal growth.

The present fertilizer comprises fibers from cellulose and/or hemicellulose. In one embodiment, the present fertilizer comprises fibers from cellulose. In another embodiment, the present fertilizer comprises fibers from hemicellulose. In much preferred embodiments, the present fertilizer comprises fibers from cellulose and from hemicellulose.

The fibers from cellulose and/or hemicellulose are preferably present in the form of a material comprising cellulose and/or hemicellulose and/or lignin. Preferably, the material is rich in cellulose and/or hemicellulose. Preferably, the material comprises 50 wt.% - 99 wt.%, more preferably 55 wt.% - 90 wt.%, even more preferably 60 wt.% - 85 wt.% of cellulose and/or hemicellulose. In preferred embodiments, the material comprises 35 - 85 wt.% cellulose, preferably 40 - 70 wt.% cellulose. Further preferably, the material comprises 10 - 50 wt. hemicellulose, preferably 15 - 40 wt.%, more preferably 20 - 35 wt.%. In further preferred embodiments, the material additionally comprises lignin, such as in a quantity of 10 - 35 wt.%, preferably 15 - 30 wt.%.

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SUBSTITUTE SHEET (RULE 26) Preferably, the material is plant material. Plant material, in this context, refers to any material obtained from plants which comprises cellulose and/or hemicellulose and/or lignin. Preferably, the material is plant material processed by physical and/or chemical. Preferred material is plant material from trees, shrubs or grasses. In much preferred embodiments, the material is wood. In other preferred embodiments, the material is and waste of the crops (corn, rice, wheat and coffee).

It is preferred that the material which provides the fibers from cellulose and/or hemicellulose of the present fertilizer is a particulated material. Particulated, in this regard, means that the particle size of the material is 0.05 - 6.0 cm, preferably 0.1 - 4.0 cm, more preferably 0.5 - 2.0 cm. Particle size is herein defined as the longest straight-line distance between opposing sides of a particle.

The fibers from cellulose and/or hemicellulose in the present fertilizer comprise covalently bonded nitrogen-containing side groups. That is, the fibers have been modified to incorporate (nitrogen-containing) side groups on the cellulose and/or hemicellulose molecules.

The nitrogen-containing side groups comprise at least one nitrogen atom. In preferred embodiments, the nitrogen-containing side group comprises multiple nitrogen atoms. In much preferred embodiments, the nitrogen-containing side groups are derived from a primary or secondary amine, preferably a primary or secondary amine which is rich in nitrogen. Nitrogen rich is defined as at least 30 wt.%, relative to molecular weight of the amine, of nitrogen atoms, preferably at least 40 wt.%, more preferably at least 45 wt.%, even more preferably at least 50 wt.% nitrogen, even more preferably at least 60 wt.%. nitrogen ("N”).

In much preferred embodiments, the nitrogen-containing side groups are derived from a primary amine.

The nitrogen-containing side groups are preferably derived from melamine (a primary amine having 66 wt.% N), urea (a primary amine having 46 wt.% N), ethylene diamine (a primary amine having 46 wt.% N)

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SUBSTITUTE SHEET (RULE 26) or diethylene triamine (a primary and secondary amine having 42 wt.% N), preferably melamine.

The nitrogen-containing side group is attached to the cellulose and/or hemicellulose backbone through a secondary or tertiary amine bond. Side groups derived from a primary amine provide side groups attached to the cellulose and/or hemicellulose backbone through a secondary amine group. Side groups derived from a secondary amine provide side groups attached to the cellulose and/or hemicellulose fiber through a tertiary amine group. The attachment of the primary or secondary amine is through a covalent bond. Thus, the cellulose and/or hemicellulose fiber is substituted with nitrogen-rich moieties as defined above through secondary or tertiary amine groups.

The quantity of nitrogen which can be present in the present fertilizer may vary within wide ranges. For example, the present fertilizer may have a nitrogen (NJ content of 10 - 500 mg N per gram fertilizer, preferably 20 - 250 mg N per gram fertilizer, more preferably 30 - 150 mg N per gram fertilizer. Nitrogen content can be determined by Kjeldahl determination, as is known in the art.

The fertilizer of the invention preferably has a particle size, defined as above, of 0.05 - 6.0 cm, preferably 0.1 - 4.0 cm, more preferably 0.5 - 2.0 cm. The fertilizer preferably has a pH of from 3.0 - 10.0, such as 3.5 - 9.0. In preferred embodiments, the fertilizer has a pH of 4.5 - 7.0, preferably 5.0 - 7.0. In alternative preferred embodiments, the fertilizer has a pH of from 6.5 - 10.0, preferably 7.0 - 9.5.

In much preferred embodiments, the fertilizer is a free flowing powder. The free-flowing powder preferably has a moisture content of from 1.0 - 15 wt.%, preferably 3 - 12 wt.%. The moisture content is preferably the equilibrium moisture content, as dictated by the humidity of the surroundings.

The invention further provides a method for preparing the fertilizer described above, comprising:

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SUBSTITUTE SHEET (RULE 26) a) providing a material comprising fibers from cellulose and/or hemicellulose; b) reacting said material with an aqueous hydroxide base, preferably sodium hydroxide, to provide a material comprising activated cellulose and/or activated hemicellulose; c) providing a primary or a secondary amine; d) reacting said primary or secondary amine with a carbonyl compound to provide a reactive intermediate; e) reacting the material comprising activated cellulose and/or activated hemicellulose obtained under b) with the reactive intermediate obtained under d) to provide the fertilizer.

The material comprising fibers from cellulose and/or hemicellulose has been defined above, and is preferably plant material, such as for example wood or bagasse, most preferably wood.

The material is reacted with an aqueous hydroxide base, preferably sodium hydroxide, to provide a material comprising activated cellulose and/or activated hemicellulose. The aqueous hydroxide base preferably has a concentration of hydroxide salt (e.g. NaOH) in water of 1 - 30 wt.%, more preferably 5 - 25 wt.%, more preferably 10 - 20 wt.%, optimally about 15 - 20 wt.%.

The reaction can be carried out by combining the material with the aqueous hydroxide base in any appropriate vessel, preferably while providing some form of mixing (e.g. stirring) and allowing the reaction to occur. In preferred embodiments, the temperature is maintained between 20 - 100 °C, in which case the reaction may be allowed to proceed for a period of 1 - 30 hours. Higher temperatures allow for a considerable shortening of the reaction time: in the preferred embodiment where the material is heated in the aqueous hydroxide solution (to 70 - 100 °C), the reaction could provide sufficient quantities of activated cellulose and/or activated hemicellulose in as little as 0.5 - 5 hours, preferably 0.5 - 2.5 hours.

Subsequently, the material comprising activated cellulose and/or activated hemicellulose is separated from the aqueous hydroxide solution.

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SUBSTITUTE SHEET (RULE 26) This may be achieved in any conceivable way, such as by decanting, filtering, centrifuging or cycloning. This provides a solid particulate material comprising activated cellulose and/or activated hemicellulose.

The material is subsequently washed, preferably to a pH of 7.0 - 9.0, more preferably 7.0 - 8.0. Said washing is preferably performed with an aqueous medium having a temperature of 20 - 90 °C, said aqueous medium preferably being water.

The method further comprises a step of providing a primary or secondary amine. Said primary or secondary amine will become the nitrogen-containing side group, to be coupled through the nitrogen atom of the primary or secondary amine.

The primary or secondary amine has been defined above: it is preferably a nitrogen-rich primary or secondary amine, most preferably a nitrogen-rich primary amine. In much preferred embodiments, the primary or secondary amine is melamine, urea, ethylene diamine or diethylene triamine, most preferably melamine.

The primary or secondary amine is reacted with a carbonyl compound to provide a reactive intermediate. The carbonyl compound is preferably a small molecular compound. A small molecular compound, in this context, is a compound which has a molecular weight of from 30 to 100, preferably from 30 - 80, more preferably from 30 to 60. The carbonyl compound is further preferably characterized by the formula CxHyO, wherein x = 1 - 5, preferably 1 - 3, more preferably 1 - 2, more preferably 1. Further preferably, y = 2 - 10, more preferably 2 - 6, more preferably 2 - 4, most preferably 2. Generally, it was found that increasing the molecular weight of the carbonyl compound decreases the reaction rate with the amine. The carbonyl compound is preferably formaldehyde, acetaldehyde or acetone, most preferably formaldehyde.

The reaction of the primary or secondary amine with the carbonyl compound is preferably performed by heating the primary or secondary amine in the presence of the carbonyl compound. The carbonyl compound is preferably a liquid at the reaction temperature, so that the carbonyl

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SUBSTITUTE SHEET (RULE 26) compound may function as solvent as well as reactant. In alternative embodiments, the carbonyl compound and primary or secondary amine are dissolved in an appropriate solvent. Appropriate solvents for this type of reaction are well-known in the art of organic chemistry. Formaldehyde, for example, is preferably used in the form of an aqueous solution, such as a 37 % formaldehyde solution (formalin).

In preferred embodiments, the primary or secondary amine is combined in a 1 : 2 or 1 : 1, respectively, mass ratio with formaldehyde, and subsequently heated, preferably while stirring, as defined elsewhere. In alternative preferred embodiments, the primary or secondary amine is dissolved in an alkaline medium, preferably having a pH of 7.1 - 11.0, preferably 8 - 11, more preferably 8.5 - 10.0, in a concentration of 0.5 - 5 wt.%, preferably 1.0 - 3.0 wt.%, relative to the total mass of the alkaline medium. The alkaline medium may optionally comprise a base; suitable bases are known in the art. In much preferred embodiments, the primary or secondary amine is dissolved in formalin, at the indicated concentration or mass ratio.

The heating can be to any suitable temperature, as is known in the art. In preferred embodiments, the temperature can be from 30 - 90 °C, more preferably 50 - 70 °C, more preferably about 60 °C. The duration of heating can be 5 - 300 minutes, preferably 10 - 120 minutes, more preferably about 40 minutes. In much preferred embodiments, the reaction between the primary or secondary amine and the carbonyl compound is performed by heating the amine (preferably melamine) in an aqueous formaldehyde solution to a temperature of 40 - 80 °C for a period of 20 - 120 minutes. This provides a solution of a reactive intermediate. The reactive intermediate may for example be an amine alcohol, depending on the chosen reactants and reaction conditions.

The material comprising activated cellulose and/or activated hemicellulose is subsequently reacted with the reactive intermediate to provide the fertilizer. The reaction may be referred to as a coupling reaction, which effects the coupling of the primary or secondary amine to the

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SUBSTITUTE SHEET (RULE 26) (activated) cellulose and/or hemicellulose, to provide a material which comprises cellulose and/or hemicellulose bearing (covalently bounded) nitrogen-containing side groups.

The reaction can be achieved by combining the solution of the reactive intermediate as obtained in step d) with the material comprising activated cellulose and/or activated hemicellulose as obtained under b), preferably in a mass ratio of 1 : 1 - 1 : 10, preferably 1 : 1 - 1 : 5.

The reaction is preferably performed by heating the material comprising activated cellulose and/or activated hemicellulose in the presence of the reactive intermediate at a temperature of 30 - 95 °C, preferably 50 - 90 °C, more preferably about 85 °C. The reaction time is preferably a period of 5 - 300 minutes, more preferably 10 - 120 minutes.

Preferably, the reaction mixture is subsequently neutralized, such as by using an acid, for example acetic acid. The pH of the fertilizer can be adjusted as needed, such as by addition of an acid or base, to a pH of from 3.0 - 10.0, such as 3.5 - 9.0. In preferred embodiments, the pH can be adjusted to 4.5 - 7.0, preferably 5.0 - 7.0. In alternative preferred embodiments, the pH can be adjusted to 6.5 - 10.0, preferably 7.0 - 9.5.

Suitable acids or bases to achieve pH adjustment are known in the art, and include any acid or base which does not hamper plant growth, and which does not degrade the fertilizer of the invention. Examples include dilute hydroxide solutions, or weak acids or bases such as ammonia /ammonium solutions, acetic acid/acetate solutions, or citric acid/citrate solutions.

In preferred embodiments, the product of the reaction is subsequently separated from the reaction mixture, such as by filtration, decanting, sieving or cycloning. In further preferred embodiments, the product is subsequently dried to provide a powder.

The reaction (e) to provide the fertilizer from the material comprising cellulose and/or hemicellulose and the primary or secondary amine is preferably performed so that the quantity of primary or secondary amine (under c) of the method) is 2 - 50 wt.%, preferably 10 - 35 wt.%, more

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SUBSTITUTE SHEET (RULE 26) preferably about 25 wt.%, of the quantity of material under a) of the method.

In preferred embodiments, the reactions are performed batch- wise, so that the quantity of material under a) and the quantity of primary or secondary amine under c) are adapted to provide a single batch of material comprising activated cellulose and/or hemicellulose under b) and a single batch of reactive intermediate under d), said single batches being appropriate to be combined so as to provide the fertilizer with the abovespecified ratio of primary or secondary amine to material comprising cellulose and/or hemicellulose.

In alternative performed embodiments, the reaction sequence may be executed continuously so as to provide the fertilizer with the abovespecified ratio of primary or secondary amine to material comprising cellulose and/or hemicellulose. The skilled person is able to convert a batch process as shown herein to a continuous process using common general knowledge and some routine experiments.

In further preferred embodiments, the fertilizer can be subjected to particle size reduction to obtain a preferred particle size. A preferred particle size is 0.01 - 6.0 cm, preferably 0.05 - 4.0 cm, more preferably 0.1 - 2.0 cm, even more preferably 0.1 - 1.0 cm, even more preferably 0.2 - 0.5 cm. Particle size reduction can be achieved by any means known in the art, such as for example grinding, milling, cutting or crushing. Grinding is preferred. Techniques for particle size reduction, including grinding, are conventionally known in the art, and any technique can be used. An example is a ball mill.

The invention furthermore provides a soil mixture comprising the fertilizer as herein defined. Soil, in this context, is to be understood broadly as any type of medium suitable to sustain at least some plant growth. Plain sand is encompassed in the definition of soil, such as for example dessert sand or river sand. Preferred is soil comprising a mixture of inorganic particles and organic matter. Said inorganic particles may be selected from clay, sand and the like. In the present context, soil is to be understood as the

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SUBSTITUTE SHEET (RULE 26) total of inorganic particles and all further organic matter which may be present in a soil used for plant growth, except for the fertilizer.

The soil may be combined with the fertilizer in any usable ratio. Preferably, the soil mixture comprises soil in a quantity of 25 - 99 wt.%, more preferably 40 - 95 wt.%, even more preferably 50 - 90 wt.%, most preferably 60 - 80 wt.%. Further preferably, the soil mixture comprises the fertilizer in a quantity of 1 - 75 wt.%, preferably 5 - 60 wt.%, more preferably 10 - 50 wt.%, most preferably 20 - 40 wt.%. In further preferred embodiments, the soil mixture may comprise, in addition to the soil as herein defined and the fertilizer, up to 10 wt.% of other components. Such components may include, for example, a source of potassium, sulphur and/or phosphorous.

In preferred embodiments, the soil furthermore comprises minerals, such as nitrogen, potassium, sulphur and/or phosphorous, in quantities sufficient to sustain at least some plant growth. A soil of the invention comprising the fertilizer of the invention has the advantage that it provides a steady nitrogen supply for prolonged periods, without leakage of nitrogen into the environment. A soil of the invention has the further advantage that it provides for improved water holding (relative to the soil without the present fertilizer), and improved aeration: the soil is more "loose” by enriching it with the present fertilizer.

The soil mixture of the invention is preferably a soil for growing plants. The soil can be present in an agricultural field, in a greenhouse, a garden, or a in container for growing plants, such as a pot. The soil is preferably potting soil, garden soil, agricultural soil or horticultural soil.

The soil mixture of the invention preferably has any pH which is convention for the type of soil in question. The pH may be of from 3.0 - 10.0, such as 3.5 - 9.0. In preferred embodiments, the soil mixture has a pH of 4.5 - 7.0, preferably 5.0 - 7.0. In alternative preferred embodiments, the soil mixture has a pH of from 6.5 - 10.0, preferably 7.0 - 9.5.

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SUBSTITUTE SHEET (RULE 26) The invention also provides a method for fertilization, comprising a step of providing soil with the fertilizer of the invention. The soil may be provided with the present fertilizer in any conceivable means. The soil can be provided with the fertilizer by combining the fertilizer with the soil, and optional subsequent mixing.

The fertilizer may be distributed on top of the soil, or it may be mixed into the soil. In preferred embodiments, the fertilizer is mixed into the soil, such as by (pre)mixing (in the case of potting soil or gardening soil), or by distribution of the fertilizer on the soil and subsequent mixing, such as by ploughing, scratching or raking (in the case of larger patches of soil, such as agricultural soil).

The mass ratio of fertilizer to soil is preferably 100 : 1 - 1 : 100, more preferably 50 : 1 - 1 : 50, more preferably 1 : 1 - 1 : 50. In preferred embodiments, the fertilizer is used in a quantity of 1 - 75 wt.%, preferably 5 - 60 wt.%, more preferably 10 - 50 wt.%, most preferably 20 - 40 wt.%, relative to the mass of the soil after enrichment with the fertilizer.

The invention furthermore provides use of the present fertilizer for promoting plant growth. Use of the invention can be in any context, such as promoting plant growth in areas where plants only grow with difficulty, or promoting plant growth so as to stimulate said growth beyond the capacity of the soil itself. Use of the invention thus may provide enhanced flowering, or increase a harvest.

EXAMPLES

Example 1: preparation of the fertilizer

Ground wood with particles having particle sizes (the longest straight-line distance between opposing sides of a particle) between 0.5 and 2.0 cm was activated in a 20 wt.% aqueous NaOH solution at 100 °C for 2 hours under stirring. The wood particles were isolated by filtration and washed with water to a pH in the range of 7.0 - 8.0.

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SUBSTITUTE SHEET (RULE 26) Melamine was dissolved in a 37 % aqueous formaldehyde solution ("formalin”) at a concentration of 2.0 wt.%. The pH of the solution was around 9.0. The solution was heated to 60 °C for a period of 40 minutes, thereby providing a reactive intermediate suitable for reaction with the activated wood.

The isolated activated wood was combined with the melamine-formaldehyde solution and heated to a temperature of 85 °C for 30 minutes under stirring. The product was subsequently filtered, washed with water and dried, and then ground using a ball mill to a particle size of 0.2 - 0.5 cm.

The quantity of nitrogen in the wood was 21,4 g N/100 g fertilizer, as determined by Kjeldahl.

Example 2: application of the fertilizer to stimulate plant growth River sand was thoroughly washed with fresh (tap) water to pH 7.5 to remove all nutrients.

The washed sand was combined with the fertilizer of the invention in four different proportions, providing sand/fertilizer (soil) mixtures having 100.0, 200.0, 300.0 and 400.0 mg N/kg of washed sand (0.470, 0.935, 1.405 and 1,870 g fertilizer per kg of sand).

Pots were filled with the sand/fertilizer mixture, and corn was seeded in the soil mixture.

On day 34, the plants were harvested for numerical comparison on the parameters

• stalk diameter (mm)

• root length (cm)

• fresh stem and leaf mass (g)

• dry stem and leaf mass (g)

• fresh root mass (g)

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SUBSTITUTE SHEET (RULE 26) • dry root mass (g)

• leaf area (cm²)

The results are shown in table 1.

Table 1: growth parameters for plants grown in plain sand using various quantities of the fertilizer of the invention.

The results show that using the fertilizer of the invention, the plant receives sufficient nutrients. The plant is able to dedicate its energy to growth, which can be seen from the increase in leaf and stem mass, and in particular leaf area. Plants without the fertilizer of the invention direct their energy to the search for more nutrients, as can be seen from higher attention given to root development in control 1.

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SUBSTITUTE SHEET (RULE 26)

Claims

1. A fertilizer comprising fibers from cellulose and/or hemicellulose, wherein said fibers comprise covalently bonded nitrogen-containing side groups.

2. The fertilizer according to claim 1, wherein the nitrogencontaining side groups are covalently bonded to the fibers through a secondary or tertiary amine group, preferably a secondary amine group.

3. The fertilizer according to claim 1 or 2, wherein the nitrogencontaining side groups are derived from a primary or a secondary amine, preferably a primary or secondary amine characterized by a quantity of nitrogen, relative to molecular weight of the amine, of at least 30 wt.%.

4. The fertilizer according to any of claims 1 - 3, wherein the nitrogen-containing side group is derived from melamine, urea, ethylene diamine or diethylene triamine, preferably melamine.

5. The fertilizer according to any of claims 1 - 4, wherein the fibers from cellulose and/or hemicellulose are fibers from plant material, preferably plant material from trees, shrubs or grasses, most preferably wood or bagasse.

6. The fertilizer according to any of claims 1 - 5, wherein said fertilizer has a particle size, defined as the longest straight-line distance between opposing sides of a particle, of 0.05 - 6.0 cm, preferably 0.1 - 4.0 cm, more preferably 0.5 - 2.0 cm.

7. A method for preparing a fertilizer according to any of claims 1 - 6, comprising: a] providing a material comprising fibers from cellulose and/or hemicellulose; b] reacting said material with an aqueous hydroxide base, preferably sodium hydroxide, to provide a material comprising activated cellulose and/or activated hemicellulose; c] providing a primary or a secondary amine; d] reacting said primary or secondary amine with a carbonyl compound to provide a reactive intermediate; e] reacting the material comprising activated cellulose and/or activated hemicellulose obtained under b) with the reactive intermediate

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SUBSTITUTE SHEET (RULE 26) obtained under d) to provide the fertilizer.

8. The method according to claim 7, wherein the primary or secondary amine is melamine, urea, ethylene diamine or diethylene triamine, preferably melamine.

9. The method according to claim 7 or 8, wherein the carbonyl compound is a small molecular compound, characterized by a molecular weight of from 30 to 100, preferably from 30 - 80, more preferably from 30 to 60.

10. The method according to any of claims 7 - 9, wherein the carbonyl compound is a compound of formula C_xH_yO, wherein x = 1 - 5, preferably 1 - 3, more preferably 1 - 2, more preferably 1, and/or wherein y = 2 - 10, preferably 2 - 6, more preferably 2 - 4, most preferably 2.

11. The method according to any of claims 7 - 10, wherein the carbonyl compound is formaldehyde, acetaldehyde or acetone, preferably formaldehyde.

12. The method according to any of claims 7 - 11, wherein

1] the reaction under b) is performed by reacting the material in an aqueous hydroxide solution, preferably an aqueous sodium hydroxide solution having a concentration of 1 - 30 wt.%, preferably 5 - 25 wt.%, more preferably 10 - 20 wt.%, more preferably about 15 wt.%, preferably at a temperature of 20 - 100 °C for a period of 1 - 30 hours; and/or

2] the reaction under d) is performed by heating the primary or secondary amine in the presence of the carbonyl compound, preferably for a period of 5 - 300 minutes, more preferably 10 - 120 minutes, more preferably about 40 minutes, preferably at a temperature of from 30 - 90 °C, more preferably 50 - 70 °C, more preferably about 60 °C; and/or

3] the reaction under e) is performed by heating the material comprising activated cellulose and/or activated hemicellulose obtained under b] in the presence of the reactive intermediate obtained under d] at a temperature of 30 - 95 °C, preferably 50 - 90 °C, more preferably about 85 °C, preferably for a period of 5 - 300 minutes, more preferably 10 - 120 minutes.

13. The method according to any of claims 7 - 12, wherein the reaction under e) is performed so tli61 the quantity of primary or secondary amine under c) is 2 - 50 wt.%, preferably 10 - 35 wt.%, more preferably

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SUBSTITUTE SHEET (RULE 26) about 25 wt.%, relative to the quantity of material under a).

11. The method according to any of claims 7 - 13, wherein after step b), the material is separated from the aqueous hydroxide solution and subsequently washed until the pH is 7.0 - 9.0, preferably 7.0 - 8.0, and wherein preferably, said washing is performed with an aqueous medium having a temperature of 20 - 90 °C, said aqueous medium preferably being water.

12. The method according to any of claims 7 - 14, wherein the material under a) is a particulate material having a size no larger than 6 cm, preferably 0.5 - 2 cm, more preferably about 1 cm.

16. A soil mixture, comprising the fertilizer according to any of claims 1 - 6.

17. A soil mixture according to claim 16, wherein said soil is soil for growing plants, preferably potting soil, garden soil, agricultural soil, or horticultural soil.

18. A method for fertilization, comprising a step of providing soil with the fertilizer of any of claims 1 - 6.

19. Use of the fertilizer of any of claims 1 - 6 for promoting plant growth

SUBSTITUTE SHEET (RULE 26)