Abstract
We examined possibility of determining total nitrogen, total carbon and crude ash concentrations in dairy cattle manures using near infrared reflectance spectroscopy (NIRS). 76 samples were collected from principal dairy farming areas in Nagano prefecture. 51 samples of those were selected to search for best set of wavelengths (1-8 filters from 19 filters) in calibrations and 25 samples were used for validations with each ingredient. Sellected wavelengths in most fitted regression equations were 2180 nm, 2208 nm, 2139 nm, 2270 nm and 2348 nm (5 wavelengths) for total nitrogen ; 2208 nm, 2180 nm, 1680 nm, 1778 nm, 2230 nm and 1445 nm (6 wavelengths) for total carbon ; and 1778 nm, 1818 nm, 2208 nm, 2180 nm, 1680 nm, 1982 nm, 1940 nm and 2310 nm (8 wavelengths) for crude ash, in order of largely absolute value of partial regression coefficients. In validations, correration coefficients between NIRS predicted and chemically observed values were 0.934 for total nitrogen, 0.971 for total carbon and 0.985 for crude ash. Standard deviations of prediction were 0.17 % for total nitrogen, 1.45 % for total carbon and 2.24 % for crude ash. The skews and biases were not significant (p<0.05), respectively. We conclude that NIRS is available to rapid measurements of total nitrogen, total carbon and crude ash concentrations in cattle manures.
