Abstract: An apparatus and a method for introducing a particulate matter along with a driving liquid, such as water, into a ground surface. The apparatus is also highly effective for perforating and thereby aerating the ground surface. The particulate matter may preferably adopt the form of a powder like substance often referred to as "polymer" and which is injected into the ground for purposes of acting as a plant food or a plant additive in various agricultural operations. The apparatus utilizes an injector device for mixing the polymer or other particulate matter with the driving liquid, such as water, at a point in close proximity to the ground surface so that there is no pre-mixing of the particulate matter and the driving liquid. The driving liquid is pumped to the injector at a high pressure and introduced into a high pressure chamber of the injector. The liquid is then forced through a very small diameter nipple opening leading to a low-pressure chamber.