A system and process for dispensing a liquid agrochemical such as ammonia into a field is disclosed. The ammonia is placed in a vessel under sufficient pressure to maintain a substantial portion of the ammonia in a liquid form. From the pressurized vessel, the ammonia is fed to a distribution manifold where it is ultimately injected into a soil through a plurality of dispensing tubes. A constant pressure flow rate control device is placed at each dispensing tube for metering the amount of ammonia fed to the soil. Furthermore, the outlet flow of each constant pressure rate control device is made to vaporize nearby the inlet flow path to create a heat exchange effect thereby cooling the inlet flow. In particular, the flow control devices allow ammonia to be dispensed from the system while maintaining sufficient back pressure and temperature within the distribution manifold to maintain the ammonia in a liquid form. By maintaining the ammonia in a liquid form, uniform and accurately controlled flow rates can be dispensed from the dispensing tubes.