The Determination of Total N, Total P, Cu and Zn in Chicken Manure Using Near Infrared Reflectance Spectroscopy

In this study, the 74 chicken manure samples from a chicken farm were used to take the diffuse reflection spectra from 12500 to 4000 cm− 1 by FT-NIR spectrometer. The total N, total P, Cu and Zn of chicken manure samples were predicted by NIR spectra. For the samples of each component, an ascending order was arranged and they were divided into calibration set and prediction set according to their content. Partial least square regression (PLSR) method was applied to construct the calibration model. Results showed that the correlation coefficients of the calibration model for total N was 0.69, the root mean square error of calibration (RMSEC) was 0.66, the root mean square error of prediction (RMSEP) was 0.80. For the models of total P, Cu and Zn, the results were r=0.86, RMSEC=0.29, RMSEP=0.34; r=0.95, RMSEC=3.46, RMSEP=5.71; r=0.94, RMSEC=14.13, RMSEP=25.21, respectively. The results indicated that the NIR spectroscopy was useful to non-destructively determine the content of total N, total P, Cu and Zn of chicken manure. As a complementary detecting method to the conventional analysis, NIR spectroscopy could significantly improve the detecting efficiency.