The invention relates to a ground treatment apparatus for loosening ground, in particular for ground (12) having grass, especially the ground (12) of sports or recreation facilities, comprising a supporting device (24), a holding device (60) held thereon and having a plurality of injection elements (58), a fluid-providing device (40), which has a fluid connection to the injection elements (58), and a reciprocating device (100), by means of which the injection elements (58) can be inserted into the ground (12) and pulled out of the ground. According to the invention, in order to provide such a ground treatment apparatus that enables better loosening of the ground, the ground treatment apparatus (10) comprises a plurality of fluid containers (106), which have a fluid connection to the fluid-providing device (40) for loading with fluid, and a valve device having a plurality of outlet valves (114), wherein each fluid container (106) has a fluid connection to at least one injection element (58), which fluid connection can be selectively opened or closed by means of an associated outlet valve (114), and that the ground treatment apparatus (10) comprises a control device (54), which controls the outlet valves (114) in order to open the respective fluid connections when the injection elements (58) are inserted in the ground (12).