Capacitance and near-infrared techniques for the real-time moisture measurement of broiler litter

• Capacitance & NIR techniques evaluated for moisture measurement of broiler litter.
• Capacitance sensor output affected by litter density and generated a linear response within certain moisture content range.
• High correlation with NIR absorbance spectra at 1400, 1900 and 1900 nm.
• NIR technique performed better than capacitance technique.

The feasibility of capacitance and near-infrared (NIR) techniques for measuring the real-time moisture content (MC) of broiler litter was evaluated. Data collection consisted of recording differential voltage signal and spectral absorption values (1200–2200 nm) for a capacitance and a NIR sensor, respectively, for broiler litter samples within 19.3%–75.1% d.b. (16.2%–42.9% w.b.) MC. Initial data analysis indicated that litter density impacted the capacitance sensor voltage. The sensor generated a linear response between 19.3% and 45.8% d.b. MC at the given bulk density (BD) and the operating moisture range further decreased as the litter BD increased. NIR data analysis indicated that the absorption bands within the 1400–1440 nm and 1900–1950 nm wavelength regions were highly correlated to the litter MC. Linear regression models relating the output data (differential voltage and absorption spectral values for capacitance and NIR, respectively) to the litter MC exhibited a high linear correlation (R2 = 0.89–0.99). Model validation results also generated high correlation values (R2 = 0.87–0.95) between the predicted and measured MC's. Overall results suggested that the NIR technique performed better than the capacitance technique because of its ability to provide rapid, non-intrusive and density-independent measurements within the selected moisture range. The NIR technique is recommended for future real-time moisture measurement on litter conveying and application equipment.