Development of Moisture Sensor Technology to Enhance Conveynace and Field Distribution of Broiler Litter
Type of Degreethesis
MetadataShow full item record
As environmental implications for land application of poultry litter become stricter, technological advancements on litter spreaders will be required to improve field performance. The inherent physical variability, moisture content and bulk density, in poultry litter makes land application difficult with spinner-disc spreaders. The overall goal of this research was to identify and develop technology to provide moisture and/or density feedback to a spreader, rate controller for enhancing litter conveyance and distribution during field application. The research objectives were to evaluate the: 1) effect of bulk density (moisture content) on metering and placement of broiler litter when using a spinner-disc spreader, 2) ability of a capacitance type moisture sensor for real-time moisture measurement in broiler litter, and 3) feasibility of near-infrared (NIR) spectroscopy for predicting moisture content in broiler litter. Results indicated that high discharge rate errors (>±15%) and statistical differences in distribution patterns (p<0.05) at a few transverse positions were determined when incorrect density values were used within a rate controller. Density treatments affected mass flow by the conveyor which further impacted the application rates and distribution patterns. These results suggested the use of the correct density value within a spreader rate controller to maintain application accuracy. The inclusion of real-time moisture or density information as a feedback to the rate controller to account for moisture/density variations was thereby proposed. Results for evaluation of capacitance type moisture sensor indicated that the sensor generated a linear response within the 16%-31% moisture range at the nominal (loose) bulk density of broiler litter. The sensor output was impacted by litter density and the operating moisture range further decreased as wet bulk density increased. Validation of the regression models relating sensor output to litter moisture content showed a strong linear relationship (R2 = 0.90-0.94) and low standard errors (<1.2%). The results suggested that a properly calibrated sensor has good potential for real-time moisture measurements in broiler litter but density impact on sensor performance must be considered. Evaluation of NIR spectroscopy indicated that absorption bands within the 1400-1440 nm and 1900-1950 nm wavelength regions were strongly correlated (R2 = 0.97-0.99) to litter moisture content. Spectral data analysis indicated that the absorbance values at 1400 nm plus 1900 nm or at 1930 nm can be independently used for real-time moisture determination in broiler litter. Overall, the NIR technique was recommended for real-time moisture measurement in broiler litter because of its rapid, non-destructive, non-intrusive and density-independent measurements. In the future, development and inclusion of a real-time moisture measurement technology, such as NIR, on a litter spreader will help improve litter conveyance and distribution during application.