Improved water utilization and management is a top priority for many farmer groups as competition for water supplies between urban and rural users increases. We have developed a prototype real-time, smart sensor array for measuring soil moisture and soil temperature that uses off-the-shelf components. The system consists of chip-controlled sensor box to which up to 4 soil moisture or temperature sensors can be attached. The sensor box also contains a device called an RFID tag which converts the sensor information to digital form and transmits it to an interrogator. The interrogator is centrally located and regularly polls the tags for data. A large number of sensors can be installed in a field and provide data wirelessly to the interrogator. The data can be used to control a Variable Rate Irrigation (VRI) system, manually, schedule irrigation, or provide information to an expert system such as Irrigator Pro for comprehensive crop management. In production quantities, the sensors and sensor box will cost well under $80 which allows for a high density of sensors in a field. The total cost of the interrogation system is not expected to exceed $1000. The prototype system has been tested successfully in the field under corn during the 2003 growing season, and peanuts and cotton during the 2004 and 2005 growing seasons. This paper will present the design of the smart sensor array and present results.