Estimation of Plant Biomass by Spectral Reflectance in an East African Grassland

Canopy spectral reflectance measurements at 0.800 and 0.675 μm were made in a grassland in Masai Mara Game Reserve, Kenya. The reflectance ratio (0.800/0.675 μm) was shown to be a reliable predictor of green biomass, accounting for 70% of the variance in green biomass values. Significant error in the biomass estimates was shown to be due to plots which contained less than 30% of the total vegetation in the live condition. Estimation error tended to increase when time of sampling departed from the interval of 1000 to 1400 hours, although this trend was not statistically significant. We conclude that the spectral reflectance technique can provide reliable estimates of plant biomass in grassland ecosystems where the proportion of live:total vegetation exceeds 30%.