Development of a prototype infrared reflectance moisture meter for milled peat

A prototype infrared reflectance moisture meter was designed, built and calibrated. Based on observations and statistical analyses, a reference waveband centred on 1800 nm and an absorption band centred on 1928 nm, were selected for measurement of wet weight basis moisture content in peat. The prototype was tested on three peat types (low-, medium-, and high-density peats) with mcwb ranging from ca. 33¯63%. Analysis of covariance of the calibration data shows that the correlations existing in the three peat types differ at 5% significance level. Based on the computed standard error of estimate, the 95% confidence limits of the prototype moisture meter were ±2.75, ±1.75, and ±3.2% mcwb, respectively, for low-, medium-, and high-density peats. However, when all peat types were grouped together, the 95% confidence limit increased to ±5.3%. The peat industry requires a noninvasive moisture meter with an accuracy of ca. ±3.0% mcwb. This implies that in order to meet the industry requirement, it is necessary to be able to distinguish between peat types. This could be done satisfactorily by manual selection in many cases but the development of an automated system would further enhance the potential of this meter.