NOVELTY - A soil improver (A), for e.g. cultivation of soils, comprises a mixture of 30-70 parts by weight of earth rock; 10-40 parts by weight of organic substances and peat, oil seed pellet, cereal pellet or -flour, compost, xylit and/or raw coal; 0.1-10 parts by weight of arbuscular mycorrhizal of all fungus form; 10-30 and 0.05-1 parts by weight of plant-available macro and micro nutrient, respectively, 5-15 parts by weight of extracts from e.g. sugar, starch, yeast, corn bran and squashed rape residue from oil extract, organic residue from e.g. food industry and 5-15 parts by weight of a catalyst.    USE - (A) is useful for cultivation and recultivation of soils, structural improvement of soils and formation and maintenance of soil fertility and initial and long-term fertilization of arable land (claimed). No biological data given.    ADVANTAGE - (A) is an effective biological process activator and conserving agent and is a bio-available substrate with excellent soil-improving properties. (A) exhibits improved release of plant foodstuffs by means of the symbiosis of soil bacteria and mycorrhizal fungi and the breakdown of foodstuffs in the soil, which results in a fertilizer sparing effect.    DETAILED DESCRIPTION - A soil improver (A), for: cultivation and recultivation of soils, structural improvement of soils and formation and maintenance of soil fertility and initial and long-term fertilization of arable land, comprises a mixture of:    (a) 30-70 parts by weight of earth rock, acid and/or basic rock flour from lava rock, igneous rock and/or plutonic rock, such as baltic sand and -flour and graywacke and clay flour (cement asbestos) in a grain size of 0.01-0.30 mm;    (b) 10-40 parts by weight of organic substances and peat, oil seed pellet, cereal pellet or -flour, compost, xylit and/or raw coal;    (c) 0.1-10 parts by weight of arbuscular mycorrhizal of all fungus form;    (d) 10-30 parts by weight of plant-available macro nutrient;    (e) 0.05-1 parts by weight of plant-available micro nutrient (trace elements);    (f) 5-15 parts by weight of an extract from sugar, starch, yeast, corn bran, corn flour, cereal bran, cereal flour, squashed rape residue from oil extract, organic residue from food-, drinks- and animal feed industry in form of an aerobic or anaerobic ferment; and    (g) 5-15 parts by weight of a catalyst.    An INDEPENDENT CLAIM is also included for the preparation of (A), comprising:    (1) mixing 30-70 parts by weight of earth rock, 10-40 parts by weight of organic substances and peat and/or raw coal, 10-30 parts by weight of plant-available macro nutrient, and 0.05-1 parts by weight of plant-available micro nutrient;    (2) mixing 5-10 parts by weight of extract from sugar, starch, yeast, corn bran, corn flour, cereal bran, cereal flour, squashed rape residue from oil extract and organic residue from food-, drinks- and animal feed industry, catalyst and 1-2 parts by weight of raw ash in the second step;    (3) homogeneously mixing the catalyst from carbon with low carbon to nitrogen ratio and carbon with high carbon to nitrogen ratio;    (4) fermenting the mixtures from the first, second and third steps; and    (5) adding 10 parts by weight of clay and 1-10 parts by weight of granulated arbuscular mycorrhizal, followed by confectioning.