Abstract: An integrated system for monitoring sap flow and simultaneously performing data-logging and automatically scheduling irrigation in a field; comprising a plurality of in situ sap flow gauges that perform its comprehensive computer-controlled tasks in the field being irrigated. This plurality of sap flow gauge can be detached from and reattached to a like plurality of plant stems as appropriate. A scaling mechanism is used to calculate crop water usage in variously-sized fields. An integrated portable computer apparatus is programmed to perform a plurality of actions including sap flow monitoring via a controller and data-logger; data-logging and automatic irrigation scheduling; a plurality of sap flow gauges; an automatic rain gage; a water meter; an irrigation valve actuator; and any auxiliary and independent weather or soil monitoring sensors. The system is connected to a PC, mounted in a weatherproof enclosure, and powered by rechargeable battery, solar panel, or AC mains power with battery backup.