An ammonia applicator system includes adjustable orifices with openings having variable sizes that can be changed remotely, without having to disassemble exit lines from a distribution manifold. In this way, the restriction of the exit lines and, thus, line flow rate can be adjusted remotely and/or automatically, even during ammonia application use. Each adjustable orifice may include a valve and an actuator that controls the valve for changing the size of the opening of the adjustable orifice. The actuator may be a rotary actuator, such as a stepper motor, and the valve may include an adjustment knob and a screw that can rotate to allow a needle to advance or regress through an opening of a valve body of the valve.