Development of new two methods based on low-cost sensors for determination of calcium carbonate contents of soils

The chemical analysis of CaCO3 contents of soils provide information about not only efficiency of soil for supplying plant with nutrients but also identification of factors affecting this efficiency in the soil. The aim of the current experiment was to develop new methods based on sensors and compare with conventional Scheibler method. The CO2 liberated by the action of HCl on CaCO3 content of the soil in a reaction bottle and an accumulation chamber was determined by pressure sensor and CO2 sensor, respectively. The CaCO3 contents of soils were estimated using the regression equation of standard curves. The CaCO3 contents of soils obtained using Scheibler calcimetric, pressure and CO2 sensor methods ranged from 0.20 to 54.74%, 0.25 to 54.10% and 0.55 to 53.05%, respectively. On the basis of linearity of calibration curve and high correlation with Scheibler calcimetric method it can be said that developed pressure and CO2 sensor methods appears to be very useful for quantification of CaCO3 contents of soils. The pressure sensor has provided the opportunity in developing a simple and handy device with an affordable cost to measure CaCO3 contents of soils as accurately as Scheibler calcimeter when compared with CO2 sensor method. Even if there is a good relationship between Scheibler calcimetric method and CO2 sensor method the cost of CO2 sensor method may limit the use in determination of CaCO3 contents of soils. However, CO2 sensor method can be used to monitor CO2 evolved in biochemical process such as respiration and fermentation.