Nutrient monitoring in agricultural fields is vital to ensuring good yield without overapplying fertilizer, which leads to devastating environmental damage and unnecessarily high operating costs. The current method of sending soil samples for off-site testing gives little data with high latency. Biodegradable in-soil monitoring units would enable high spatial resolution information without prohibitively complex logistics. In this thesis, I present a hybrid biodegradable system featuring passive readout of amperometric sensors. To create this system, I designed a custom potentiostat IC in the TSMC 180nm node and developed a biodegradable flip chip bonding method to attach this chip to a paper substrate on which an antenna and sensor structure are printed. This passive readout technique was also adapted to monitor biodegradable batteries in an agricultural field demonstrating feasibility of autonomous readout by an agricultural ground robot.