An irrigation system comprising: a pressurized water source; subsurface microporous irrigation tubing, the irrigation system configured to selectively couple the pressurized water source to a header of the subsurface microporous irrigation tubing via a first path, a second path, or a third path; the first path including a first pressure regulator disposed between the pressurized water source and the subsurface microporous irrigation tubing, the first pressure regulator being configured to output a relatively low fluid pressure to the header; the second path including at least one injector and a second pressure regulator disposed between the pressurized water source and the subsurface microporous irrigation tubing, each of the at least one injectors configured to inject an amendment into the second path, outputs of the at least one injectors coupled to an input of the second pressure regulator, the second pressure regulator being configured to output a relatively high fluid pressure to the header, the relatively high fluid pressure being higher than the relatively low fluid pressure; the third path including a bypass valve coupling the pressurized water source to the input of the second pressure regulator and bypassing the at least one injector; a recirculation valve coupled to a footer of the subsurface microporous irrigation tubing and the input of the second pressure regulator; and a recirculation pump coupled between the recirculation valve and the second pressure regulator. a pressurized water source; subsurface microporous irrigation tubing, the irrigation system configured to selectively couple the pressurized water source to a header of the subsurface microporous irrigation tubing via a first path, a second path, or a third path; the first path including a first pressure regulator disposed between the pressurized water source and the subsurface microporous irrigation tubing, the first pressure regulator being configured to output a relatively low fluid pressure to the header; the second path including at least one injector and a second pressure regulator disposed between the pressurized water source and the subsurface microporous irrigation tubing, each of the at least one injectors configured to inject an amendment into the second path, outputs of the at least one injectors coupled to an input of the second pressure regulator, the second pressure regulator being configured to output a relatively high fluid pressure to the header, the relatively high fluid pressure being higher than the relatively low fluid pressure; the third path including a bypass valve coupling the pressurized water source to the input of the second pressure regulator and bypassing the at least one injector; the first path including a first pressure regulator disposed between the pressurized water source and the subsurface microporous irrigation tubing, the first pressure regulator being configured to output a relatively low fluid pressure to the header; the second path including at least one injector and a second pressure regulator disposed between the pressurized water source and the subsurface microporous irrigation tubing, each of the at least one injectors configured to inject an amendment into the second path, outputs of the at least one injectors coupled to an input of the second pressure regulator, the second pressure regulator being configured to output a relatively high fluid pressure to the header, the relatively high fluid pressure being higher than the relatively low fluid pressure; the third path including a bypass valve coupling the pressurized water source to the input of the second pressure regulator and bypassing the at least one injector; a recirculation valve coupled to a footer of the subsurface microporous irrigation tubing and the input of the second pressure regulator; and a recirculation pump coupled between the recirculation valve and the second pressure regulator.