Abstract: A coulter disc assembly is pulled by a tractor or other motorized vehicle to create a trench in the ground into which seeds are dispensed. This mounting arrangement of the present invention allows a farmer to inject agricultural additives, such as either liquid or dry fertilizer, into the ground so as to come into contact with the seed immediately after the trench is created and before it is covered over. The mounting arrangement consists of an elastomeric mounting block adapted to connect to a coulter disc frame. A rigid guide rod extends from the mounting block downwardly toward the ground. One end of a tube is connected to a supply of agricultural additives and the other end to the lower end of the guide rod. As the coulter disc passes through the ground to create a trench, the lower end of the guide rod is carried in the trench. As the guide rod engages the side walls of the trench, the rubber mounting block allows the guide rod to pivot rearwardly in the direction opposite the travel of the disc.