PROBLEM TO BE SOLVED: To provide a weed-proof material and method for using same, the material having a short curing time and high initial strength development and capable of reducing grass-cutting effort and ensuring weed-proof sustainability and environmental conservation； and to provide a method for using such a material.SOLUTION: According to the present invention, there are provided (1) a weed-proof material comprising magnesium oxide, calcium aluminate, and soil； (2) the weed-proof material of (1) further comprising gypsum； (3) the weed-proof material of (1) or (2) in which the calcium aluminate is a CaO/Al2O3 molar ratio of 1.0-3.0 and the amount of impurity is 15 mass% or less； (4) the weed-proof material of any one of (1) to (3), further comprising magnesium chloride and/or magnesium sulfate； (5) a method for using a weed-proof material, the method comprising covering the ground with the weed-proof material of one of (1) to (4) by spreading the material on the ground and sprinkling water thereon； and (6) a method for using a weed-proof material, the method comprising covering the ground with the weed-proof material of one of (1) to (4) by kneading the material with water and spreading or spraying the material on the ground.SELECTED DRAWING: NoneCOPYRIGHT: (C)2018,JPO&INPIT【課題】硬化時間が短く、初期強度発現性が高く、草刈の労力を軽減でき、防草の持続性と環境保全が確保できる防草材及びその使用方法を提供する。【解決手段】（１）酸化マグネシウム、カルシウムアルミネート及び土壌を含有してなる防草材、（２）さらに、石膏を含有してなる（１）の防草材、（３）カルシウムアルミネートが、ＣａＯ／Ａｌ２Ｏ３モル比１．０～３．０、不純物が１５質量％以下である（１）又は（２）の防草材、（４）さらに、塩化マグネシウム及び／又は硫酸マグネシウムを含有してなる（１）～（３）のいずれかの防草材、（５）（１）～（４）のいずれかの防草材を地面に敷き詰めてその上に散水して被覆する防草材の使用方法、（６）（１）～（４）のいずれかの防草材を水で練混ぜて地面に敷詰または吹き付けて被覆する防草材の使用方法、である。【選択図】なし
