NOVELTY - Producing superabsorbent pellets and/or of a fibrous material from crop residues of monocotyledonous flowering plants (preferably maize) cultivation, comprises cutting the maize stalks planted in the ground of the field below the lowest cob of the stalks; cutting the less leafy stalk segments as close to the ground as possible; harvesting the less leafy stalk segments; cutting the harvested less leafy stalk segments into stalk sections; and providing a mechanical impact to the stalk sections.    USE - The method is used for producing superabsorbent pellets and/or of a fibrous material from crop residues of monocotyledonous flowering plants (preferably maize) cultivation. The superabsorbent pellets f1 are used as (i) absorbent/filter/elimination unit of gaseous and/or liquid products originating from animal excrements, biogas production sites, meat processing sites, treatment of exhaust gas from thermal energy production, gaseous and liquid hydrocarbons, including oil and its derivatives; or (ii) support for chemical/biological treatment of any substrate, the support possibly including an active principle, useful as processing aid. The fibrous matter f2 or product is used as a plant substrate, a plant substrate component and/or peat substitute. The superabsorbent pellets f1, fibrous matter f2, or product is used as plant substrate component, water absorbent for crops, packaging material, construction material, cat litter or their components (all claimed).    ADVANTAGE - High-performance absorbents and/or fibrous materials and new and improved method for the production of superabsorbent pellets and/or of a fibrous material from crop residues are provided. The method is swift and industrial. The method makes it possible (i) to separate easily and efficiently pith, bark and leaves; (ii) to get some superabsorbent pellets which water absorption capacity is greater than or equal to 5 times its own weight and which largest dimension (length) is greater than or equal to 2 mm; (iii) to get at an industrial scale and simultaneously and distinctively superabsorbent pellets and a fibrous material with different exploitable functionalities; and (iv) to get some superabsorbent pellets which density in a non-compressed form of 10-100 kg/m3.    DETAILED DESCRIPTION - Producing superabsorbent pellets and/or of a fibrous material from crop residues of monocotyledonous flowering plants (preferably maize) cultivation, comprises (a) cutting the maize stalks planted in the ground of the field below the lowest cob of the stalks, so as the less leafy stalk segments, which are preferably higher than or equal to -in an increasing order of preference-30; 50; 70 cm, stay on the field; each less leafy stalk segment including a spongy core, a stalk bark wrapping the core and a leafy matter wrapping the stalk bark or born by the stalk; (b) cutting the less leafy stalk segments as close to the ground as possible; (c) harvesting the less leafy stalk segments cut in step (b); (d) cutting the, in step (c), harvested less leafy stalk segments into stalk sections which largest dimension in mm- preferably their length-is comprised between -in an increasing order of preference-5-50; 8-40; 10-30; (e) providing a mechanical impact to the stalk sections of step (d) so as to 1. separate their spongy cores from their stalk barks, as well as the leafy matter, 2. to transform the stalk barks into elongated fiber pieces; and 3. to obtain a mix containing: f4. spongy cores forming the superabsorbent pellets fraction; f5. elongated fiber pieces forming the fibrous matter fraction; and f6. leaf matter forming the leafy fraction; (f) separating the 3 fractions from each other; (g) recovering the three fractions f1-f2-f3; and (h) possibly reducing the f1 superabsorbent pellets up to a smaller pellet size so as their largest dimension in mm -preferably their length- be comprised 0.1-20 mm, preferably 1-5 mm. INDEPENDENT CLAIMS are:    (1) a device notably for implementing the method defined above, comprising (m.i) unit for cutting the maize stalks planted in the ground of the field below the lowest maize cob of the stalks; the unit (m.i) being preferably the unit of i.e. a conventional mower, a reaper, a harvester, a thresher, or a combined harvester-thresher; (m.ii) unit for cutting the less leafy stalk segments; (m.iii) unit for harvesting the less leafy stalk segments cut in step (b); the unit (m.ii) and (m.iii) being preferably the unit of i.e. an usual agricultural machine, such as a self-loading cutter vehicle; (m.iv) unit for cutting the, in step (c), harvested less leafy stalk segments into stalk sections; (m.v) unit for providing a mechanical impact to the stalk sections of step (d); (m.vi) unit for separating the 3 fractions f1-f2-f3 from each other, the unit preferably comprising a coarse-mesh sieve with a mesh width preferably greater than or equal to 40 mm and more preferably greater than or equal to 60 mm and a slot sieve with a width preferably less than or equal to 20 mm and more preferably less than or equal to 15 mm, and even more preferably comprised 5-10 mm; the sieve; one of the sieve(s) being a vibrating sieve; (m.vii) unit for recovering the three fractions f1-f2-f3; (m.iv'&-v') Possibly unit for generating an air flow -preferably a fan equipped with a rotor and blade(s)/knife(s), for transporting the stalk sections of step (d); (m.vi') Possibly a cyclone for extracting the 3 fractions f1-f2-f3 from their transporting air flow;    (2) superabsorbent pellets f1, obtained notably from the method defined above, made from the spongy/porous stalk core of monocotyledonous flowering plants (preferably maize) and having: a water absorption capacity -expressed in multiple of its own dry weight and given in an increased order of preference- greater than or equal to 15-19 and comprised of 20-50; and/or a density in a non-compressed form -expressed in kg of dry matter/m3 and given in an increased order of preference-comprised of 10-100; and/or a density in a compressed form -expressed in kg/m3 and given in an increased order of preference- greater than or equal to 100-400; and comprised of 100-700; and/or a pellet maximum dimension (PMD)-expressed in mm and given in an increased order of preference: 5 less than or equal to PMD less than or equal to 30; 6 less than or equal to PMD less than or equal to 20; 8 less than or equal to PMD less than or equal to 15; or comprised of 0.1 less than or equal to PMD less than or equal to 5; 0.3 less than or equal to PMD less than or equal to 3; 0.5 less than or equal to PMD less than or equal to 2;    (3) fibrous matter f2, obtained notably from the method defined above, made from the stalk bark of monocotyledonous flowering plants (preferably maize) and having a water absorption capacity -expressed in multiple of its own dry weight - greater than or equal to 5, preferably to 6, and more preferably comprised between -in an increased order of preference-4 and 15; 5 and 10; 6 and 9; and a 3-dimensional porous structure; and    (4) products obtained by forming of the composition comprising (i) superabsorbent pellets f1, (ii) a binder, (iii) an agent for retardation of flames and/or inhibition of microbial growth and/or hardening of the composition, (iv) a mineral filler, (v) fibrous matter f2, and (vii) one of the components (ii) to (v), the products being preferably in the form of cubes and/or slabs.