The purpose of this research is to design and realization of an electronic apparatus which is able to control the process of irrigation that depending on soil moisture .This apparatus organize the process of irrigation, when the level of soil moisture under a specific value that it was chosen depending on water field capacity of crop ,it operates the pump which connected with it, and when the moisture level reaches that value the pump stops working. The apparatus consists of two parts: The first part: An electronic circuit using a number of operational amplifiers ,some electronic elements ,and voltmeter to measure voltage between load resistance which is in serial with resistance between two probes that set in soil. The second part: An electrical part ,which provides a secure connection between the previous electronic circuit and water pump. This study was carried out on a simple of black soil .The relation between electrical resistance of soil and volume of water used in irrigation was drawing for three values of distance between probes and power supply. We found an intense declination curves for small values of used water volume.