Quantification of MBM adulteration in compound fertilizers and composts by NIRS

Abstract

The objective of this study was to demonstrate the feasibility of using near infrared reflectance spectroscopy (NIRS) to determine MBM content in compound fertilizers and composts. One hundred fourty adulterated compound fertilizer samples were prepared in the laboratory by mixing 4 types of compound fertilizers with 3 types of MBM randomly at different levels of 0.1%-10.0% (w/w). One hundred twenty adulterated compost samples were obtained by mixing 41 compost samples with 28 MBM at different levels of 3.0%-24.0% (w/w). NIRS calibration models were developed using the partial least squares (PLS) regression method. Results showed that the coefficients of determination for calibration (R2) and validation (r2) were 0.996 and 0.622, 0.988 and 0.722 for adulterated compound fertilizers and composts respectively. The ratios of prediction to deviation (RPD) were 8.84 and 1.87 for them respectively. These results indicated that NIRS could be used to quantify the adulteration of banned MBM in compound fertilizers with high prediction accuracy, and be insufficient to determine the content of MBM in composts due to low prediction accuracy.

Keywords

• compost
• compound fertilizer
• MBM
• NIRS
• quantification