Evaluation of EC-5 soil moisture sensorsfor real-time determination of poultry manure or litter moisture content

Moisture content (Psi) of poultry manure or litter is an important property of the material. Relating manure or litter Psi to its ammonia (NH3) emission is conducive to assessing and/or controlling real-time ammonia emissions from the manure or litter. However; means to measure manure or litter on a real-time basis is lacking. This study was carried out to characterize the operational performance of a commercially available soil moisture sensor for measuring V of meat-bird (broiler and turkey) litters and laying-hen manure. The Psi tested ranged from 27.1% to 65.7% for broiler litter, 22.8% to 56.1% for turkey litter, and 11.0% to 75.0% for layer manure. Bulk density (rho) ranged from 318 to 468 kg m(-3) (20 to 29 lb ft(-3)) for the broiler and turkey litters and from 151 to 943 kg m(-3)(9 to 55 lb ft(-3)) for laying-hen manure. Linear regression equations were developed to relate the sensor output to Psi and rho for the meat-bird litters and to Psi for the laying-hen manure, all yielding good fit (R-2=0.95 -0.99). An uncertainty analysis performed on the developed calibration equations revealed average errors in the V estimation of +/- 7.1% estimated value for the poultry litters and +/- 6.7% estimated value for the laying-hen manure. Litter temperature was found to have a small impact on Psi measurement by the sensor, 0.31% of measured mV per degrees C (0.17% per degrees F) deviation from the mean operating temperature over the range of 4 degrees C to 24 degrees C (39 degrees F to 75 degrees F). Results of the study indicate that when properly calibrated, the soil moisture sensor offers a reasonable means for real-time measurement of poultry litter or manure moisture content.