PURPOSE: To obtain an agricultural covering material useful for growing in a plastic greenhouse, having excellent balance of sunlight absorption and sunlight transmission properties by blending an agricultural covering material with a heat-sensitive color changing dyestuff component to reversely change color between a dark color at a low-temperature side and a colorless state at a high- temperature side.

CONSTITUTION: An agricultural film (thickness: 10-2,000μm, preferably 20-1,000μm) is blended with 0.2-10wt.%, preferably 0.5-7wt.% heat-sensitive color changing dyestuff component to reversely change color to a dark color at a low temperature and to a colorless state or light color at a high temperature in a temperature range of 0-5°C, preferably 0-2°C to give an agricultural covering material which is laid in a plastic greenhouse to promote natural snow melting. A composition consisting of a electron donative coloring substance [e.g. 3,3',3"- tris(p-dimethylaminophenyl)phthalide], an electron acceptor (e.g. phenols) and an azomethine (e.g. benzylidinelaurylamine) and liquid crystal are used as the heat-sensitive color changing dyestuff component.