| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a soil conditioner which, when mixed with soil, can give mixed soil with a high heat absorption capacity upon light exposure and permits satisfactory plant growth by selecting an inorganic porous soil conditioner being in the form of porous particles, having a specified or higher porosity, and having a specified or lower surface lightness index. SOLUTION: There is provided an inorganic porous soil conditioner being in the form of porous particles, having a porosity of at least 25 vol.% and having a surface lightness index of at least 50%. It is desirable that its porosity is at least 30%, and that its lightness index is at most 30. Examples of starting materials for the soil conditioner include a product obtained by granulating a mixture comprising a zeolite powder and a carbon powder and a product obtained by granulating sludge or dust containing casting sand discharged from a foundry. The material is fired at 400-800 deg.C for 1-4 hr to obtain an inorganic porous soil conditioner. It is desirable that its particle diameter is 1-20 mm in order to ensure water permeability. This conditioner has a high cation exchange capacity and a high capacity of retaining nutrients for plants.</p> |
