TECHNOLOGY FOCUS - AGRICULTURE - Preferred Composition: A sludge fermenting bacteria is further added to the soil improver. Preferred Method: A surface coal soil in abandoned mines is covered with the soil improver by more than 25% weight ratio of the soil improver to the surface coal soil.    TECHNOLOGY FOCUS - BIOLOGY - Preferred Components: The white rot fungus is selected from the species of Trametes versicolor, Pleurotus ostreatus, Phanerochaete sordida, Trametes hirsutus, Fusarium culmorum, Phanerochaete chrysosporium, and a deposited microorganism of deposition number (KCCM 10725P). The plant with heavy metal removing activity is selected from Betula schmidtii, Betula costata, Pinus densiflora, Fraxinus rhynchophylla, Fraxinus sieboldiana, Rhododendron mucromulatum, Weigela subsessilis, Acer pseudosieboldianum, Rhododendron schlippenbachii, Salix hulteni, Betula platyphylla, Salix koreensis, Alnus japonica, Stephanandra incisa, Mignolia sieboldii, Callicarpa japonica, Acer mono, Quercus mongolica, Corylus sieboldiana and Tilia amurensis. ACTIVITY - Fertilizer; Plant growth stimulator. The efficacy of the soil improver containing sludge, degraded sawdust and white rot fungus, was tested for plant growth stimulating activity in a mine-destructed coal soil. One year old seedling of Betula schmidtii was planted in an abandoned mine restoration region. After digging a hole having 20 cm depth, 30 cm width in the mine-destructed coal soil for planting, two experiment groups, a (control) group not having the developed compost soil, and (test) group having 500 cc of compost soil treatment with the soil improver, were randomly distributed in a manner of 5 replicates per treatment. In each replicate, planted tree in a soil, 8 pieces of cellulose fabrics was set in 5 cm depth and periodically taken away to evaluate microbial activity according to time course after addition of soil improver. After planting, tree growth, amount of chlorophyll and variation of growth was periodically monitored. After 1.5 and 2.5 months, the growth responses of selected tree according to treatment of soil improver were investigated. For investigating the growth response of tree according to treatments of soil improver, the quantity of chlorophyll of selected tree species were measured. It was observed that the quantity of chlorophyll was increased at least 2 times after treatment of soil improver in the plants from (test) group, compared to the control, suggesting that nutrient supplement effect by soil improver was definite. In a research of new root development, measured after 8 months, it was also observed that the new root development of trees was very quickly progressed by the treatment of soil improver.    MECHANISM OF ACTION - None given.    EXAMPLE - The soil improver for plant restoration around abandoned mine area was prepared. Sawdust was mixed with mesophilic or thermophilic microorganisms and the culture solution of white rot fungi degrading cellulose in an amount of (5%) in sawdust. The mixing ratio of sludge to the sawdust was 65-67% of the water content of mixture. Aeration was done by forced air injection at the bottom of decomposition reactor. Aeration was carried out at a rate of 0.2 l air/minute per 1 l compost soil during first decomposition step and then carried out at a rate of 0.1 l air/minute per 1 l mature soil in the second decomposition step to maintain suitable temperature of decomposition because as decomposition was carried out, the volume of the compost soil decreased. After finishing stable decomposition by added white-rot fungi and mesophilic or thermophilic microorganism which degraded organic matter, generated heat more than 65degreesC and was used for removing the moisture to obtain the soil improver.