An In-Situ Soil pH Sensor With Solid Electrodes

Rapid analysis of soil properties is an imperative component of precision agriculture. Soil pH, one of the essential facets of precision farming, helps to decide the type of crop to be grown in the field and also to predetermine the productivity of the crop. The analysis of soil pH is of utmost importance, as it plays a crucial role in controlling crop yield. However, the conventional method of soil pH analysis is time-consuming and requires sophisticated instruments and a skilled workforce. Here, an all-solid electrode, in-situ soil pH sensor is demonstrated, which mitigates many of the drawbacks associated with the traditional method of pH analysis. The soil pH sensor uses antimony as the sensing electrode and an in-house developed, novel solid reference electrode. The solid reference electrode is made by coating KCl saturated Araldite on the surface of an AgCl-coated Ag electrode. The pH sensor exhibits a linear response in the pH range from 3 to 8, with a sensitivity of −38.2 mV/pH and a correlation coefficient of 0.99.