Analysis for Tannin Concentration in Sericea Lespedeza by Near Infrared Reflectance Spectroscopy
- W. R. Windham ,
- S. L. Fales and
- C. S. Hoveland
Near infrared reflectance spectroscopy (NIRS) has become widely accepted for the analysis of forage quality parameters. However, this technology has not been tested adequately for its capacity to analyze forages for antiquality parameters. Our objectives were to evaluate the utility of NIRS to determine the tannin concentration of sericea lespedeza [Lespedeza cuneata (Dum.-Cours.) G. Don.] and to quantify the seasonal tannin fluctuations of various high- and low-tannin entries. We assayed tannin concentration of nine sericea entries grown on a Cecil coarse sandy loam (clayey, kaolinitic, thermic Typic Hapludult) near Athens, GA, and harvested in June, August, and October in each of 3 yr. Calibration equations were obtained by regression of the vanillin-HCl tannin values on NIR spectra from 100 randomly selected samples using a scanning NIR monochromator spectro-computer system. Five wavelengths were required to derive the best equation with a standard error of calibration of 14.0 g kg−1 dry matter (DM). Analysis of the remaining samples gave a standard error of analysis of 15.0 g kg−1 DM, which was similar to the standard of the reference method in our laboratory (SE = 12.1 kg−1 DM). Differences in tannin concentration of sericea lespedesa were due to an entry ✕ season ✕ year interaction (P < 0.0001). Tannin concentrations increased in summer but returned to lower levels in autumn. These fluctuations were greater in the high- than low-tannin entries (P < 0.05). We conclude that NIRS can analyze the tannin concentration of high- and low-tannin sericea lespedeza with an accuracy similar to the reference method. Use of NIPS should allow breeders to screen larger numbers of sericea lespedeza lines than would otherwise be possible.
Copyright © . .