Assessing nitrogen content of golf course turfgrass clippings using spectral reflectance

摘要

Turfgrass clipping samples of two different species were obtained from a commercial golf course and their reflectance was measured using a dual type spectroradiometer under artificial illumination three hours and 51 hours after mowing. For the creeping bentgrass, the reflectance values in green band (520-580 nm) and the NIR band (770-1050 nm) increased as the nitrogen content increased. For the hybrid bermudagrass+perennial ryegrass blend, no general trend was observed. Four wavelength bands at 550,680, 770 and 810 nm were selected to develop and compare several regression models with varying number of independent variables. All models performed well (R~2>O.87) and predicted the nitrogen content within +-1.0 percent for creeping bentgrass clippingsamples. A discrimination analysis showed that the regression model with a single wavelength variable performed as well as the models with more number of wavelength variables.