PURPOSE: To obtain a controlling material for release of an agrochemical having not only function of controlling release of an agrochemical, etc., but also func tion of improving soil by extremely simple and inexpensive production facilities by utilizing a natural material not causing fear of secondary environmental disruption.

CONSTITUTION: An agrochemical, etc., are impregnated to stuck to a great number of pores of particles composed of coral fossil as a material. On the other hand, the diameters (d) of the particles are uniformed by taking advantage of the characteristic of water solubility of calcium carbonate as a main component of the coral fossil and duration time of release of the agrochemical, etc., impregnated and stuck to the pores, to soil is estimated and controlled from a dissolution and extinction time (t) of the particles.