Hamzah, YanuarUmar, LazuardiSetiadi, Rahmondia Nanda2016-02-102016-02-102016-02-10wahyu sari yenihttp://repository.unri.ac.id/xmlui/handle/123456789/7921Plants need nutrients that can be derived from the soil and from outside in the form of fertilizer. The amount of fertilizer used on certain conditions varies depending on the type of soil, crops and plantations. The composition and quality of the soil varied and plays role in the fertility of crops and required the use of sensors that can measure soil nutrients to determine the specific value of the optimal fertilizer, especially for oil palm plantations to make efficiency of fertilizer and costs savings. In this research, a nutrient sensor works based on the measurement of impedance changes due to the ionic nature of the land affected by dissolved fertilizer in the soil has been designed. The sensor works at a given excitation frequency from 50 kHz up to 10 MHz of 10mV amplitude with three levels of concentration of urea fertilizer, KCL and TSP. The characterization results showed the phase shift and amplitude changes relevant to fertilizer concentrationenNutrientsSoilFertilizerNutrient sensorPhase shiftAmplitudeUR-Scientific Work Lecturer